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

Axle codes

 Post Reply Post Reply
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: Axle codes
    Posted: 04-January-2020 at 6:01AM
I'm sure this has been posted somewhere, but I'm looking for an axle code decoder. Specifically, my axle code is 1. 

2.50?
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 5086
Post Options Post Options   Thanks (1) Thanks(1)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 04-January-2020 at 7:24AM
this example shows a door tag code '2' and states 3.00:1 gear in the text


my first guess would be that it's a 2.75:1 gear

for whatever reason 1978 door tag axle codes are pretty hard to find
72 GT Ute
   
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 12911
Post Options Post Options   Thanks (1) Thanks(1)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 04-January-2020 at 8:41AM
i looked in my 74 manual and it starts at a "2" no #1 shown Confused
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: 5086
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 04-January-2020 at 2:41PM
same with the 1976 decoder i found online
72 GT Ute
   
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 (1) Thanks(1)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 04-January-2020 at 3:15PM
We have tons of info on the site, but not as much for the 77 to 79 cars. If you check this link:


we have all the info year by year including door data plate. The data plate info isn't there for 77 to 79 but 1976 shows a 2 is an open 2.75:1 diff.  The 1978 info shows only a 2.50:1 and a 2.75:1 were the only ratios available.
Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

GTS.org Admin
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 12911
Post Options Post Options   Thanks (1) Thanks(1)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 04-January-2020 at 4:05PM
hmm, since you have the body off... look at the front of the 3rd member, there should be a tag on one of the bolts... about the 10'clock position... it will have the ratio on it Wink since you know the history since new chances are its still on there?
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: 5086
Post Options Post Options   Thanks (1) Thanks(1)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 05-January-2020 at 3:53AM
and if the tag is not present from Day 1 there's a reason, anything can be in there

there's always the old fashioned way ...

trans in Neutral, jack 1 rear tire off the ground

can you turn the tire very easily? if yes it's an open differential

if No it may be a Trac-Loc and you'll need to jack both rear tires off the ground

rotate a tire until the valve stem is at 6:00 (bottom) or 12:00 (top) whichever is your preference

now mark the driveshaft in such a way that you can determine when it has completed 1 full turn,
a simple horizontal line 1/2 way between top & bottom will do

now rotate the tire slowly counting how many rotations the driveshaft makes,
stop the tire after 1 complete rotation

how many rotations did the driveshaft make, and how much of a partial rotation?
did it stop exactly on a complete rotation or is it over or under 1/2? how much?

for a Trac-Loc or other Limited Slip that holds the rear tires together solidly (not totally whipped out) the revolutions you counted are the gear ratio

for open diff's or whipped out LS units with only 1 tire off the ground divide your driveshaft revolutions by 2 to find your ratio

the last remainder of an incomplete revolution is the decimal fraction of the ratio so try to be accurate in estimating the partial revolution
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: 05-January-2020 at 4:23AM
The body is still sitting on this car (my car), it's the donor body that is off the car (though that body was bolted  back to the frame to transport it from Indiana).

My car is sitting out in the equipment shed. As far as I know, the only time anything has been done with the third member is when me and a buddy removed it around '98 to replace the gasket. I will have to check the tag, it should still be there.

Otherwise yes, the next time I had it on concrete I could also do the old 'count the driveshaft rotations' trick. I'm sure it probably is a 2.50 in there, the car ran about 2500 rpm on the interstate going 70 mph.

I will rebuild the rear end to 3.55 anyways, but this is really more of an exercise in decoding everything since it's original, and learning some more about the history of the car I didn't know.
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
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: 05-January-2020 at 11:48AM
I suspect your are correct, that it's likely a 2.50:1 rear gear.  Rock's method would work to check the ratio, or if you pull the third member at some point, count the teeth and do the math.

If you have a tag on the diff, post it here and I will see if I can decode it for you.

When you upgrade, don't junk the 2.50 or 2.75 gears.  They are no longer available new.
Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

GTS.org Admin
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: 08-January-2020 at 1:08PM
is it an "S" code car?
400 usually had the 2.5 axle.
"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
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 12911
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 08-January-2020 at 4:46PM
 i have an "S" code 400 parts car and the door tag says it has a 3.00 in it ...
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
handsofstone View Drop Down
Senior Member
Senior Member
Avatar

Joined: 13-April-2018
Location: Northeast
Status: Offline
Points: 2179
Post Options Post Options   Thanks (0) Thanks(0)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 09-January-2020 at 3:25PM
My S code has a 2.75 tag on it.
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: 12-January-2020 at 3:09AM
On the later cars (77-79) 2.5 was standard axle for the 400.
Some Brainiac at ford said "Let's give 'em the big engine, a C6, and then add 2.5 gears to take away any semblance of performance"
Apparently a practical joke on their buyers.
Wanna see a 78 T-bird with a 400 really wake up? Swap in a 3.5 chunk.
"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
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: 13-January-2020 at 5:01PM
This all reminds me I still need to go check that tag.

Oh! Were these 8" or 9" rear ends?
78 LTD II sports touring package (blue), father original owner
67 Mustang (5.0)
69 Mach 1 428 SCJ Drag Pack
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 12911
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 13-January-2020 at 6:02PM
not sure on the later cars but 72-76 had mostly 9" but some had 8"
several ways to tell......  the back of the housing is curved with just 2 dimples it's an 8", if it has an extended area for the ring gear on the back it's a 9"
also looking at the front 3rd member 8" has more of a grid pattern on the reinforcing webbing than the 9"
also if you can remove all the nuts with a socket and extension it's an 8" if 1 or 2 are behind the pinion bearing part of the housing it's a 9"Wink
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
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: 14-January-2020 at 10:22AM
Shouldn't be any 8" rears after 72...
But, Ford.
So never say never.
"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
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 12911
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 14-January-2020 at 4:50PM
that 74 4dr i parted had an 8"
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
 Post Reply Post Reply
  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 0.094 seconds.