The Ford Torino Page Homepage
Forum Home Forum Home > Model Specific Forum > 1977-1979 Ford and Mercury
  New Posts New Posts RSS Feed - LTDII AOD conversion?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

LTDII AOD conversion?

 Post Reply Post Reply Page  12>
Author
Message
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Topic: LTDII AOD conversion?
    Posted: 09-August-2020 at 9:53AM
My 78 LTDII has a 351M/C4. I'm debating conversion to an AOD but as you can imagine there is very little information out there on it.

I know the flexplate in AOD is same number of teeth as my C4, but I'd have to use the lighter weight C4 flexplate in the AOD, as well as my starter.

I have found AOD conversion kits for 351M so it will bolt up to the block.

What I don't know is what other modifications would be required as far as driveshaft length and if any modifications are required for the transmission cross member or if it will work as is.

Right now I'm in the midst of a frame off restoration.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 899
Post Options Post Options   Thanks (1) Thanks(1)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 10:37AM
The 351M and 400 are big block bell housing patterns. I don't know how someone had put an AOD behind one, but the only small block pattern came behind the earliest 400 block.

The AOD requires a TV cable or rod, which connects to the carburetor at a linkage similar to the kick down rod of older carbs. But it is a special geometry required, to provide the proper pressure rise of the ATF as the throttle is opened. At idle the test pressure, at the special test movement(throttle is forced open slightly by a special tool(chunk of steel the same thickness as an "X" bit)), it has to be 33psi right there. I think the spec was 30-35psi or close to that, I recall 33psi being the right point.

So figure out your block to trans bolt pattern first. If they can be connected, then the TV cable is the only hard part. The AOD uses the same flex plates as any later cars, from 1980-2001. Those are all interchangeable, except for the balance. You will have to have the early flexplate, which is 28oz imbalanced. The 50oz began in 1985 I think, but it overlapped years because Ford didn't change everything at once. Lo-po 302 models of 1985-1988ish would be the old firing order, and the 28oz balance I believe.

AOD's use the newer small starters, which are vastly better than the old large type. If you go to the AOD, make the starter the ring terminal trigger terminal version(or convert it). The first used spade terminals, which had corrosion issues eventually. That's an easy thing to update.
Don
73 Ranchero GT 351C-4V 3.70 gears, to build a keeper
73 Ranchero Sport "72 front end", floor shift/console, planning EFI 351-3V &4R70W
92 Lincoln Mark VII SE, OBDII 347/4R70W
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 5089
Post Options Post Options   Thanks (1) Thanks(1)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 10:53AM
the crossmember should be the least of your problems if there are multiple hole locations in the frame mount tabs,
or both transmissions may even use the same crossmember location?

i would calculate driveshaft length when you have both transmissions and the adapter kit side by side. the AOD will also need a 31 spline slip yoke.
i'm pretty sure you'll be shortening the shaft so just a cut & balance, swap the yoke w/ new joints will get that done.

the flexplate needs to do 4 things right; tooth count, balance weight, converter stud bolt pattern and offset

you're correct in that your C4 should be the same 164 tooth count that the AOD uses, the balance weight for your 351M is 28oz-in same as 289, 302 before 1985, 351C, 351W and 400. they all use the same weight except 302 when it went to 50oz-in in 1985 IIRC. the 2 you need to work on are the converter stud pattern and the offset. C4 usually uses a 10.5" stud pattern while the FMX, AOD & C6 usually use a larger 11.5" or 11 7/16" pattern. you'll find them listed either way, they are essentially the same. from what little i remember the C4's use a different offset than the FMX, AOD and C6 but some say if everything else is right they'll swap, IDK.

i would go straight to an FMX / AOD 164 tooth flex for a 351C, 351M, 351W or 400 engine for a 99% fit

personally i'd also skip the adapter plate and move to a 351W rather than replant the 351M,
unless you're upgrading it to a 400 internally? the 351W is still correct to the H vin code.

or if you're interested the 351M can be 'corrected' to perform on a decent level, that means over-all efficiency not turning it into a pig ... sorry but they already have that covered. the issue lies in the lack of both static and dynamic compression ratios, barely 8:1 with retarded camshaft timing doesn't cut it, it can be corrected Wink


Edited by Rockatansky - 09-August-2020 at 11:00AM
72 GT Ute
   
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 5089
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 10:58AM
don't forget the throttle pressure valve cable kit for the AOD,

the pressure has to be set using a gauge, too little pressure and it'll smoke the trans in 3 minutes

better to have a tad more pressure than a tad less Thumbs Up
72 GT Ute
   
Back to Top
fordpower View Drop Down
Senior Member
Senior Member


Joined: 02-September-2010
Location: willseyville,ny
Status: Offline
Points: 1609
Post Options Post Options   Thanks (0) Thanks(0)   Quote fordpower Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 11:14AM
So the 164 tooth from my 79 fmx will work. I just bought a 85 ltd aod
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 12915
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 11:55AM
bell bolt pattern will be your major hurtle, unless it a thick adapter plate , most will work out fine if the adaper puts the tranny back you'll need to consider torque convertor spacing driveline may need shortened? and mount position... you'll need the cable for the pressure and set correctly like stated
JOHN
74 GRAN TORINO S&H CLONE
74 VETTE CUSTOM
90 S10 BLAZER 4X4 LIFTED
77 CELICA CUSTOM
75 V8 MONZA SUPERCHARGED
79 COURIER VERT. SLAMMED
75 VEGA V6 5 SPD
70 CHEV C10 P/U
68 MUSTANG FB CONVERSION
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 5089
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 12:34PM
72 GT Ute
   
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 899
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 09-August-2020 at 1:34PM
I think I also have a picture of a 400 with that odd looking rear side.

I had an AOD set down into my 73 Ranchero before stopping work on it. The AOD will set fine on one pair of the cross member holes, but if an adapter plate is used, it will need altering. It looked like a C6 driveshaft will be close, my car came with the C6. The C4 uses the other pair of holes, was my guess.

That 85 AOD you have, it isn't a police model is it? The 80's police Crown Vics used a weird shift pattern(VB internals). Those have a manual 2nd gear shift position, and no 1st gear position. The difference in those is inside the VB, one valve chamber in particular. I never changed mine, but considered it when I learned of that. I owned both an 85 and 86 P71 CV, and also bought a spare 351W/AOD to rebuild(that was about 1994).

I agree on the 351W swap, the large block 351M and 400 are less than ideal. I love Cleveland heads, but that weight and low compression sucks.

The AOD can handle some power, but not much in 80's stock form. The "A" OD servo is a must, but I would swap most of the guts from a later 4R70W, including the wider OD band. I have those spare parts unfortunately, I was collecting for a close ratio 4R, and got sent the wide ratio stuff instead.

I just found out that one sun gear shell is super rare(the AODE unique part). I need one of those for sure for my 92 Mark VII, and maybe one later for my work truck if I don't retire first. I'm putting a 347 into my Lincoln, with a 4R that has the AODE planetary etc(four parts). That will make it the same gearing as an AOD, close ratio, and work well with the 347 and stock 3.27 gears. I have an AOD that I built with a new AODE sun gear shell, so I think I'll be taking that apart soon. I also have a 94 Mustang GT(AODE), and might pull that too given how rare that part is.


Edited by 72 RS 351 - 09-August-2020 at 1:39PM
Don
73 Ranchero GT 351C-4V 3.70 gears, to build a keeper
73 Ranchero Sport "72 front end", floor shift/console, planning EFI 351-3V &4R70W
92 Lincoln Mark VII SE, OBDII 347/4R70W
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 21-August-2020 at 4:01PM
Originally posted by Rockatansky Rockatansky wrote:

the crossmember should be the least of your problems if there are multiple hole locations in the frame mount tabs,
or both transmissions may even use the same crossmember location?

i would calculate driveshaft length when you have both transmissions and the adapter kit side by side. the AOD will also need a 31 spline slip yoke.
i'm pretty sure you'll be shortening the shaft so just a cut & balance, swap the yoke w/ new joints will get that done.

the flexplate needs to do 4 things right; tooth count, balance weight, converter stud bolt pattern and offset

you're correct in that your C4 should be the same 164 tooth count that the AOD uses, the balance weight for your 351M is 28oz-in same as 289, 302 before 1985, 351C, 351W and 400. they all use the same weight except 302 when it went to 50oz-in in 1985 IIRC. the 2 you need to work on are the converter stud pattern and the offset. C4 usually uses a 10.5" stud pattern while the FMX, AOD & C6 usually use a larger 11.5" or 11 7/16" pattern. you'll find them listed either way, they are essentially the same. from what little i remember the C4's use a different offset than the FMX, AOD and C6 but some say if everything else is right they'll swap, IDK.

i would go straight to an FMX / AOD 164 tooth flex for a 351C, 351M, 351W or 400 engine for a 99% fit

personally i'd also skip the adapter plate and move to a 351W rather than replant the 351M,
unless you're upgrading it to a 400 internally? the 351W is still correct to the H vin code.

or if you're interested the 351M can be 'corrected' to perform on a decent level, that means over-all efficiency not turning it into a pig ... sorry but they already have that covered. the issue lies in the lack of both static and dynamic compression ratios, barely 8:1 with retarded camshaft timing doesn't cut it, it can be corrected Wink

I am keeping my 351M, not that I'm in love with the motor because there's nothing easy about it, but it's the motor that came with the car, and this is kind of a special car. I got a 400 crank for it and will be boring it out to make it a 408 stroker. Fixing the retarded cam timing and some dome pistons (I'll need the 400 pistons anyway) can bump the compression up. Ford Muscle did a nice article where they made a 468 ft-lb torque and 380 hp 400 for $2000. It no doubt will cost more, but I've been following this plan for mine.

ANYWHO, I need to decide if I want to go through the insane PITA and expense to switch out to an AOD. I drove this thing all over hell with its C4 but it only has 2.75 in the rear, and that really needs to go. However, on my 67 Mustang with 14" tires and 3.55 in the back, it's not fun taching 3000 rpm just to go 60 mph with a C4.

Hemmings has a nice article on the swap in general.

https://www.hemmings.com/stories/article/ford-aod-overdrive-transmission


78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 899
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 21-August-2020 at 4:44PM
The AOD has close ratio gears, the 1/2/3 being about the same as a C4 or C6. If you go to the AOD, I suggest upgrading a few things for the torque level, and to help it in 1st and 2nd. The "lower" 1st gear makes the rear diff, easier to choose. You can use a 3.25 or 3.50 gear and it'll take off like almost two steps higher, say a 3.70 to 3.90 etc. The math is easy if you already know what you want with the C4 etc.

The wide ratio gears are fairly easy to come by, from any 4R70W. Those change only the 1st and 2nd gears, leaving 3rd and 4th alone. Four parts swapped change those gear ratios, planetary, ring gear, sun gear, and sun gear shell.

You'd definitely want the wider OD band, and that requires the later sun gear shell and reverse drum(preferably the 98+ mechanical diode reverse drum). Throw in the four clutch intermediate pressure plate, and the guts end up being most of the parts from a 4R trans. You can buy those from eBay often, or many trans parts stores. I even have some spare parts like them.

Most of your cost is the labor to build one, find a shop that you can trust.
Don
73 Ranchero GT 351C-4V 3.70 gears, to build a keeper
73 Ranchero Sport "72 front end", floor shift/console, planning EFI 351-3V &4R70W
92 Lincoln Mark VII SE, OBDII 347/4R70W
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 5089
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 22-August-2020 at 5:38AM
with a 408 i'd go with a C6


technically not a stroker, the 400 came with the 4" stroke crank, same block & heads, you're just upgrading from 351M to 400 with a .030" overbore to make 408 and no M because it's a 400

or you could say it's a 351M bored & stroked to 408. then it would be a 408M i guess

but anyway, no Censoreding way a C4 is going to hold up behind a 408 unless you baby it. even then you should have enough low end TQ to hurt it bad and i still worry about the FMX / AOD platform. the low end TQ is why i'm having a hard time jumping on the wide ratio bandwagon. true the LTD II is a sled but the 408 should be able to handle it easily. you can get the low ratio planet set in a C6 too, run even a 2.75 or 3.00 gear and it'll be no slouch coming off the line, then when it's in 3rd / regular D range it'll still be right for the mph


another direction is a std ratio C6 and Gear Vendors OD

big car, big motor, big transmission Wink
72 GT Ute
   
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 899
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 22-August-2020 at 10:44AM
Cool, I didn't know the C6 had a different ratio option to buy. That helps a lot, the wide ratios were used to allow higher rear gear numbers to lower rpm's at highway speeds. So even a C6 you could use likely two steps of change of the rear gear ratio. With a 408 it would do fine with I'd say 3.00 or 3.25 gears and the wide ratio, that is to say, great acceleration and maybe feasible rpm's on the highway.

An overdrive gear is great but it takes some work to have it survive a lot of torque. The 4R70W has guts that are able to handle it in stock form, thus the "70" rating in the name. But the lesser transmission like the C4 and AOD, they need some upgrading to handle much above stock or mild engines. The parts are out there, you just have to figure them out etc.
Don
73 Ranchero GT 351C-4V 3.70 gears, to build a keeper
73 Ranchero Sport "72 front end", floor shift/console, planning EFI 351-3V &4R70W
92 Lincoln Mark VII SE, OBDII 347/4R70W
Back to Top
72FordGTS View Drop Down
Admin Group
Admin Group
Avatar
GTS.org Admin

Joined: 06-September-2005
Location: Ontario, Canada
Status: Offline
Points: 4142
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 22-August-2020 at 11:46AM
FWIW, I have a 408 in my 1972 and I am running a C6 with 2.75 gears and 26.5" tires.  My engine is a fairly mild build, with a bump in compression with TMI pistons and a mild roller cam (custom grind).  It pulls fine with 2.75 gears, it has no shortage of low end power.  With this setup, the car runs at about 2700 RPM at 70 MPH.  I almost always drive my car on the highway, so I didn't want lower gears.

I considered an OD transmission, but too much hassle/money with the bell housing issues to run a AOD with the 351M/400 since it uses the 385 series bell housing. On top of the cost of the bell housing, a high performance AOD build is pricey compared to a old C6.  So I had my C6 rebuild with a Broader kit (std gearing), for a fraction of the cost.  In the long term, I'd like to go to 3.25 gears and a Gear Vendors OD, but that's a big investment.  I think that'd be the ultimate setup for my car, giving it a big more snap off the line and and also lower the cruise RPM, but for now, it's great as is.  

If you can't afford a GV OD or don't want the hassle of trying to adapt an AOD, consider just running a C6.  With a built 408 it will run fine and cruise RPM will be okay with the proper rear gears.


Edited by 72FordGTS - 23-August-2020 at 2:25AM
Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

GTS.org Admin
Back to Top
Steve M. View Drop Down
Senior Member
Senior Member


Joined: 08-June-2019
Location: Florida
Status: Offline
Points: 625
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve M. Quote  Post ReplyReply Direct Link To This Post Posted: 22-August-2020 at 12:32PM
FWIW, I'm running a mild 351W  with an FMX right now.  After doing some research,  the cost of upgrading to an AOD is about the same as going with the Gear Vendors setup. I'm saving up now for the AOD.  The AOD  can be worked on by any number of transmission shops. Parts are readily available and its Ford's replacement for the FMX. Right now my FMX is running strong with no leaks. Don't like fixing what isn't broken.  I've got too many other things that need attention on this car 1st . 
Steve M.
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 899
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 22-August-2020 at 12:54PM
For the AOD idea, also keep in mind the AOD is made for either a carburetor that has the proper AOD TV linkage on it, or the common Fox Mustang throttle bodies. Attaching the TV to another carb is not that simple or easy.

The ideal trans is a 4R70W, and a stand alone controller, but those can be $400 or were a long while ago. I'm working towards an Explorer(late 1997) 302 system, the PCM and wiring harness. That'll run any 302 and 4R70W base, other engines would need a special distributor modification(it's a cam synchronizer in those(DIS)). So I'm debating on a 302 or a 351W based block engine(big price difference). Then the transmission is a straight forward deal, work out the shifter, drive shaft and mounting.
Don
73 Ranchero GT 351C-4V 3.70 gears, to build a keeper
73 Ranchero Sport "72 front end", floor shift/console, planning EFI 351-3V &4R70W
92 Lincoln Mark VII SE, OBDII 347/4R70W
Back to Top
Steve M. View Drop Down
Senior Member
Senior Member


Joined: 08-June-2019
Location: Florida
Status: Offline
Points: 625
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve M. Quote  Post ReplyReply Direct Link To This Post Posted: 22-August-2020 at 1:12PM
The Holley carb on my car is good to go for an AOD.  I got the kit to make that change. Still keeping an eye out for the transmission. 
 There's a shop not far from me that does that conversion for the  Mustang guys. I think they sell kits for doing that conversion. They are up in Hudson Florida. Haven't checked it out yet.  
Steve M.
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 10:47AM
I had no idea C6 could be modified to OD. I'm going to have to look into the GV OD. If I were to go that route, I'd probably go something like 3.73 for the rear end (or whatever it was for the 9") with OD. If GV OD is stupid expensive, the Broader wide ratio C6's are still a pretty penny but is a good compromise for off the line acceleration.


78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
Steve M. View Drop Down
Senior Member
Senior Member


Joined: 08-June-2019
Location: Florida
Status: Offline
Points: 625
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve M. Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 11:05AM
The GV unit is an underdrive/overdrive unit. All the information is on their website. The set up I looked at gives you six forward gears. Some people really like it and others removed it soon after installing  For me the cost is similar. Since my Gran Torino is a driver, the AOD made for a better choice. 
Steve M.
Back to Top
Steve M. View Drop Down
Senior Member
Senior Member


Joined: 08-June-2019
Location: Florida
Status: Offline
Points: 625
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve M. Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 11:07AM
I forgot to mention.  LTD IIs are, in my opinion,  beautiful. 
Steve M.
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 11:09AM
I have zero experience with underdrive/overdrive transmissions, I have read a lot about it on their website though, and see it's essentially giving you 6 gears.

I really seriously would consider that for the C4 in my 67 Mustang, it's just not cool with the 3.55 trak locs in the rear now.

Price is not a whole lot different than rebuilt wide ratio from BF, but I would have to buy the C6 and have it rebuilt ($900 for rebuild), in addition to getting the new tail shaft. The GV set up would probably set me back $1000 more than getting a BF wide ratio transmission.

I do agree with the sentiment, AOD sounds like a non-starter at this point.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 11:13AM
Originally posted by Steve M. Steve M. wrote:

I forgot to mention.  LTD IIs are, in my opinion,  beautiful. 

Perhaps I'm biased, but I agree 700%. I have a 67 Mustang Coupe, a 69 Mach 1 428 SCJ, but this is my favorite of them all. The sentimentality to it probably helps that, but even in highschool, I loved these cars. 

As a freshman, there was a kid in our school who had an Elite and I loved that car because it reminded me of our LTDII we had when I was a kid. Little did I know in just two years I'd get a chance to buy that very same car back from the guy dad had sold it to about 10 years prior. So I did, and it was my car through highschool and college.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 899
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 11:27AM
I don't know how the Gear Vendor's shift function works, if that would be enjoyable.

The AOD has a few quirks of its own though. The AOD has a unique lock up feature unlike all others. The lock up is only in 3rd and 4th gear, and it is continuous. There is no lock up in 1st or 2nd gears. It's like two different two speed transmissions, the first gears are like normal torque converter trans gears. Then it has a big rpm drop to 3rd gear(1:1), because of the lock up right then, and it stays locked up in 3rd and through 4th.

That center input shaft is long and small, very weak for any performance use. That shaft engages splines that are welded onto the torque convertor housing. So 3rd/4th gears see exactly engine rpm, the TC is not part of the power flow in those gears.

The aftermarket one piece shaft which replaces both stock shafts, that eliminates lock up completely. Then all four gears work through a normal type TC, multiplication in all gears. That also reduces some fuel mileage on the highway. Most people love that shaft for the performance it gains, and they are fine with the extra rpm in 4th.

My stock 90-92 Mark VII's all had the AOD and 3.27 gears, with 26.5" tires(225/60/16) at 70mph the engine's at 2000rpm.

I would compare the choices more than just looking at costs, for the AOD, GV OD, and 4R70W for example. The shift rpm's for the AOD are not easily altered, stock is in the 4500rpm range. 2nd to 3rd is always lower than 1st to 2nd, by a good 300rpm+ for sure. Getting the AOD to survive power at the 350+ level, often needs some internal improvements not done by rebuild shops. I've seen online pictures and descriptions of most of that, but I would prefer to have to do less of that special modifying. The high dollar performance shops are most surely familiar with all of that, but the prices will be as high as any you've heard of.

The 4R70W can be built easily by any decent local shop, and nothing really special is needed until you get above 450-500hp. Those use a cable shifted linkage, some going into from the rear of the trans. So shifter choice and cable etc, are things to work out.  The controllers for it are now many, you need to source that before going deep in cost for the trans. But in use, the shifting is programmable to whatever you need, and it will be the same all the time. The shift pattern for the AOD and 4R70W are different than older C4/C6 three speeds. The AOD has "1 D N R P", so five positions. The 4R70W has "1 2 D N R P" so an extra position on the shifter.

I've had AOD's in multiple cars, and the 4R70W in three so far. I'm ready to upgrade my keeper Lincoln to a 4R, I hope to get to my Ranchero next year to do that last.
Don
73 Ranchero GT 351C-4V 3.70 gears, to build a keeper
73 Ranchero Sport "72 front end", floor shift/console, planning EFI 351-3V &4R70W
92 Lincoln Mark VII SE, OBDII 347/4R70W
Back to Top
Steve M. View Drop Down
Senior Member
Senior Member


Joined: 08-June-2019
Location: Florida
Status: Offline
Points: 625
Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve M. Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 11:28AM
It's going to be fun either way. 
Steve M.
Back to Top
72FordGTS View Drop Down
Admin Group
Admin Group
Avatar
GTS.org Admin

Joined: 06-September-2005
Location: Ontario, Canada
Status: Offline
Points: 4142
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 12:11PM
You probably won't save much if any going C6 with a GVs OD unit compared to built AOD or 4R70W.  The advantage to the C6 is you can build it now and add the GV OD unit later.  Plus the C6 is bullet proof.  If you had a small block bell housing, AOD is definitely the easier simpler route.  But a big 408 torque monster with the large bellhousing changes things and I agree with Rock, which is why I built my car by his recommendations.  There are a few members here that have GV ODs and all I recall are great reviews.  


Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

GTS.org Admin
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 5:02PM
Originally posted by 72FordGTS 72FordGTS wrote:

You probably won't save much if any going C6 with a GVs OD unit compared to built AOD or 4R70W.  The advantage to the C6 is you can build it now and add the GV OD unit later.  Plus the C6 is bullet proof.  If you had a small block bell housing, AOD is definitely the easier simpler route.  But a big 408 torque monster with the large bellhousing changes things and I agree with Rock, which is why I built my car by his recommendations.  There are a few members here that have GV ODs and all I recall are great reviews.  



I was more going for lack of complexity in C6 vs AOD or 4R70W.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 23-August-2020 at 5:22PM
Another option is to pick up a $100 C6 off Marketplace, take it to my local rebuilder to rebuild (it was $900 to rebuild my C4, including converter), and get the Broader Performance wide-ratio gear kit for $400 and have them use that. I'd have about $1400 into a wide ratio C6. Then I could put a trac-loc 3.0 or 3.25 in the rear for just a little more pep.

Broader Performance used to have a wide-ratio C4 as well, I wonder why they stopped making that one.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
Big Bird View Drop Down
Senior Member
Senior Member
Avatar

Joined: 25-August-2013
Location: New York
Status: Offline
Points: 3862
Post Options Post Options   Thanks (0) Thanks(0)   Quote Big Bird Quote  Post ReplyReply Direct Link To This Post Posted: 24-August-2020 at 2:18AM
Along with "lack of complexity" the C6 won't need to have an adapter to bolt up to the big-block trans pattern. 4R70 controllers and wiring were in the neighborhood of $800 a few years ago, add a trans adapter, rebuild costs, driveshaft mods, and maybe flexplate/torque converter costs as well...
Cheaper/simpler to use a 351W, or get a Gearvendors add-on overdrive for the existing trans.
"What we do in full frontal view, is more honest than your cleaned-up mind."
Randy
1979 T-Bird
2005 F-150 STX RCSB 4.6, 3.55 LSD
How the Heck does a REGULAR CAB SHORTBED weigh over 5200 pounds?
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 5089
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 24-August-2020 at 4:10PM
Originally posted by Lizer Lizer wrote:

Another option is to pick up a $100 C6 off Marketplace, take it to my local rebuilder to rebuild (it was $900 to rebuild my C4, including converter), and get the Broader Performance wide-ratio gear kit for $400 and have them use that.


run that idea by your builder and ask him "What if the C6 core needs hard parts ... are they included in the price or extra? IMO going with the Broader complete transmission would be a bargain considering the total package including experience putting that package together. don't get me wrong i like to support my local guys but there's no telling what you'll get inside a core and all the little nifties that Broader does will be ups & extras
72 GT Ute
   
Back to Top
Lizer View Drop Down
Member
Member


Joined: 04-January-2020
Location: SW Michigan
Status: Offline
Points: 54
Post Options Post Options   Thanks (0) Thanks(0)   Quote Lizer Quote  Post ReplyReply Direct Link To This Post Posted: 25-August-2020 at 1:11AM
Originally posted by Rockatansky Rockatansky wrote:

Originally posted by Lizer Lizer wrote:

Another option is to pick up a $100 C6 off Marketplace, take it to my local rebuilder to rebuild (it was $900 to rebuild my C4, including converter), and get the Broader Performance wide-ratio gear kit for $400 and have them use that.


run that idea by your builder and ask him "What if the C6 core needs hard parts ... are they included in the price or extra? IMO going with the Broader complete transmission would be a bargain considering the total package including experience putting that package together. don't get me wrong i like to support my local guys but there's no telling what you'll get inside a core and all the little nifties that Broader does will be ups & extras

I agree, I had the pricing of the 1200hp C6 in my head. At $1700 for the wide ratio package, I don't think the local shop can do it for that. It costs about $900 to get a new rebuilt TracLoc chunk from several vendors on Ebay, and they can't do it for that either.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
fordpower View Drop Down
Senior Member
Senior Member


Joined: 02-September-2010
Location: willseyville,ny
Status: Offline
Points: 1609
Post Options Post Options   Thanks (0) Thanks(0)   Quote fordpower Quote  Post ReplyReply Direct Link To This Post Posted: 25-August-2020 at 1:54AM

how do you identify the yr on an AOD
Back to Top
 Post Reply Post Reply Page  12>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.125 seconds.