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Tremex TKX 5 speed information and Swap info

Printed From: The Ford Torino Page
Category: Powertrain Specific Forum
Forum Name: Transmissions
Forum Description: For discussion relating to all Ford Transmissions
Printed Date: 21-April-2024 at 10:15AM
Software Version: Web Wiz Forums 12.06 -

Topic: Tremex TKX 5 speed information and Swap info
Posted By: Eliteman76
Subject: Tremex TKX 5 speed information and Swap info
Date Posted: 10-February-2024 at 12:00PM
There are a few folks stepping into the Tremec TKX world and updating their rides with Tremec's latest and greatest 5 speed. 
For this posting, I have been going through MDL for my needs, so I am referring to them. 
There are other Tremec dealers that are great to work with. If you use a company, post up info and part numbers.
Key points here is sharing info and helping each other out. But I'm not liable for your finances LOL

What is the TKX 5 speed from Tremec? The long of the short, it's the current aftermarket offering for folks wanting to step into the modern era, and give your ride more breathing room to run down the road without the joys of getting passed by a Prius at 80MPH spinning 4,000+ RPM in 4th gear. like doing fun smokey burnouts, but want to get better than single digit MPG?

Then you need to strongly consider stepping out of the last century and step into the modern world of 5 speeds. I'd bring up 6 speeds, but let's be honest. Most applications a double overdrive T-56 magnum is overkill unless you are turning 130+ speeds regularly. 

Tremec's YouTube all-new TKX video" rel="nofollow -" rel="nofollow -

I will edit and add details as I have time but for anyone who has done the swap or is well versed in this topic, please feel free to chime in here so we have a central database for TKX info.
I have a number of pictures and videos but I have been slow-going about getting things sorted out on my computer. 5+ years of not keeping things well sorted has been grueling to clean and organize!

The good: 
There are guys out there there pushing 1,000+ HP through one of these gear boxes and the transmissions are taking the abuse.
The features the TKX offers is way up there for the cost of entry.

The bad: 
This isn't your grandfather's Toploader 4 speed. You HAVE to make sure certain things are done to properly allow for the install. Mainly, doing you due diligence and checking bell house runout and recording it. I recorded mine and emailed pictures and video back to MDL to make sure for warranty purposes I have proof showing it was verified as per Tremec's requirements.

Tremec requires no more than .005"  (five thousandths of an inch). 
This may mean using mis-alignment dowel pins at times. Below I have posted links for info and videos helping explain the process. It's not a difficult process. 

Multiple articles and videos have been posted, but for reference:
MDL" rel="nofollow -
American Powertrain:
Silver Sport

In case of runout issues, replacement adjustable 1/2" diameter dowel pins can be purchased from places like RobbMC:" rel="nofollow -

RobbMC:" rel="nofollow -
(From their site: 

Bellhousing alignment is critical to ensure smooth shifting and maximum clutch life. The hole in the rear face of the bellhousing should be concentric with the crankshaft within .005" (.010 TIR).

Unfortunately, many aftermarket (and even some stock) bellhousings are not as concentric as they should be. This may be due to a problem with the bellhousing and/or the engine block.

Once the amount and direction of the misalignment are determined, offset dowels can be used to correct the problem. Unfortunately, a bit of trial and error is usually required to get the offset dowels pointed in the right direction.

At least two other companies currently make offset bellhousing dowels. Both brands make their dowels with a screwdriver slot which is to be used to rotate the dowels.

"Brand L" dowels are designed to be pressed into the block. Unfortunately they either fit so tight they have to be removed in order to rotate them, or they fit so loose they won't stay at the proper angle. (The instructions that come with the "Brand L" pins even state that the alignment must be rechecked every time the bellhousing is removed). "Brand L" dowels come in two sizes; one for GM and one for Ford/Mopar. The Ford/Mopar size is a compromise. This means they fit so tight in a Mopar engine block that they usually have to be pounded in with a big hammer and are nearly impossible to remove let alone rotate.

"Brand M" dowels slip easily into the engine but the block must be drilled and tapped in two places so that set screws can be installed to prevent the dowels from rotating once they are pointed in the correct direction. This is difficult at best and nearly impossible if the engine is still in the vehicle. "Brand M" dowels are available only for GM engines.

RobbMc bellhousing dowels are unique. They slip easily into the engine block and are designed to be turned with an open end wrench rather than a screwdriver. Once they are pointed in the correct direction, a screw (which runs down the center) is tightened which prevents the dowel from rotating. No need to pound the pins in and out. No drilling and tapping required. No need to recheck the alignment if the bellhousing is removed. Three sizes are available so they fit each engine correctly. Dowels are longer than stock so engine plates can be used.

Ford 1/2" Dowel Part numbers:
PN 1014 - .007 offset
PN 1015 - .014 offset
PN 1016 - .021 offset

MDL:" rel="nofollow -

The tool you will need will be a magnet base dial indicator. I went with the elcheapo option due to budget and how seldom I will use a dial indicator, I wound up using Harbor Freight's option. 
63521" rel="nofollow -
Digital option:
63613" rel="nofollow -

Magnetic base:" rel="nofollow -
I normally would push for much more expensive tools when it comes to anything precision, but for this application I got repeatable results and called it a day. 
Other factors like they only offer it in a long input shaft setup direct from Tremec.
Tremec no longer offers a short input shaft kit like the 351C and FE engines used when paired to Toploaders. 
351W cars were also equipped with the 164 tooth flywheels with 11" clutch packages in earlier Torinos/Mustangs, but I am not an expert when it comes to 351W Windsor based versions. 

While it's possible to retain a stock mechanical linkage, upgrading to a hydraulic setup can be done! There are others that have done cable conversions as well. 

From my experience of originally swapping in a Tremec TR3550 (TKO series) from the Toploader 4 speed, the improvement in drivability was amazing. Overdrive without a doubt was a true game changer and makes the ride entirely different. 

Much like going from C4/C6 to an AOD/AODE/4R70W or even lately the 6R80 6 speed automatics...overdrives just take away a lot of the stresses placed on the drivetrain and make highway driving better for you and your vehicle with the added fun of keeping that deeper gearing for light to light or any other sort of fun.

Now...with that said I am going to use Modern Driveline here for basic info. This is the Ford car offerings." rel="nofollow -

Now there are 26 spline and 10 spline offerings. 
In case you are curious, most all ford offerings in the 4 speed Toploader days were the 10 spline.

As times progressed, 26 spline clutch discs have become the norm.
Clutch types when the 72-74 cars were out were the 3 finger "long" style. Most aftermarket stuff and Modern manual transmission cars are running diaphragm style clutches.

For reference, MDL's site breaks out difference clutch sizes:" rel="nofollow -

Material type also varies: Organic, Kevlar/Organic, and Kevlar/Kevlar.
A lot of options make this confusing but keep in mind your vehicle is a system. 
The system is composed of a lot of different variables.

Much like if you want to pull a trailer hauling 16,000 pounds, you are not pulling it with a Toyota Prius. 
Same thing goes for your clutch. You need to make sure the flywheel, clutch kit and the rest of the driveline are up to task on this.

Personally, in my experiences in the last few years I've leaned to working with MDL. They have an in-house guy that does nothing but clutches, built around your specific usage application.
Your Tremec dealer of choice can help you get the right setup. 

I used them back in 2017 with my TR3550/TKO swap and the kit I got from them was the right choice.

I will say based on my experience of both Long style 3 finger clutches and the diaphragm kits, my diaphragm style was a nice improvement in feel and how it "grabbed" as I released the clutch pedal and hammered through the gears. 
Not that the long style is bad, just a different way of getting A-B with less pedal effort and more clamping force. 

Adapting to a factory Ford Toploader 164 Tooth flywheel Bell house:
I had to purchase the following from MDL to adapt the TKX to my factory Toploader bell house. 

MD-401-2108 - Spacer Plate

Notes from MDL:
Spacer Plate Assy., Wide pattern SBF/BBF to 3550/TKO, TKO500/600, TKX with standard input shaft, with hardware.
Recommended to check stack-heights prior to installation.
385 series engines MUST check stack heights prior to installation of transmission.

NOTE from my experience: 
It's advisable to confirm stack distances regardless of your combo to make sure of no issues. 
I took my bell house and placed on a flat surface and measured to the mating surface of the bell-to-transmission surfaces and sent pictures to MDL.
MDL uses that dimension to confirm how thick of a spacer is needed between the TKX and the Bell house. 

SS-11-26 Disk, SS, 11, 26 spline 1-1/16" hub
I was originally running a 10 spline input on my TR3550/TKO, but upgraded to the 26 spline disk as the TKO I got was a 26 spline input. 

MD-601-1330-31 Slip Yoke 
ATF-QT  Oil, ATF, Amsoil Synthetic Transmission Fluid, 1 quart bottle QTY 3

This was for my application as I am running 1330 U-joints on my GTS compared to the original 1310's the 72-73 Toploader cars came stock with. 

Notes: 31 spline, 1330-16 U-joint, TKO/TKX/Magnum and C6/FMX, Forged Steel

Concerning release bearings:
There have been ongoing issues with parts stores and places like Amazon not having the correct bearing. Package mix-ups or vendor issues, hard to say. 
I went directly to SKF's website as I wanted a premium heavy duty bearing.

Normally I lean to Timkem Bearings for my needs as they are still producing bearings in the USA and Japan. I tend to solely use Timken for wheel bearings anymore unless it's a breakdown situation and I can't get them.

In my case, SKF has the heavy duty version for the 72-74 stock mechanical linkage available. 
N1439 Clutch Release Bearing
N1444 is also listed however it is a slightly smaller bearing. Likely for the inline 6 / 302 3 speed cars. 
This is the closest I could find to my throwout bearing was the N1439 that I have been running for the last 15-20 years for the Toploader, TKO and now TKX with stock linkage.

For those running Hydraulic throwout bearings, this won't be applicable but again, MDL and other transmission suppliers will have who they recommend. 

Driveshaft notes:
As a warning, make sure you retain a 3.5" outer diameter driveshaft on the 72-79 cars. 
DO NOT let a shop talk you into thinking a 3" shaft will be OK.

From personal experience I screwed up and let the local Omaha shop go with a 3" driveshaft tube instead of a 3.5" because he said he had built plenty of driveshafts in his life and not had problems with street cars. 
I found out the hard way when I went from my 3.50 to 2.75 gearing, sure the 3" OD was OK, but when I went to 3.50, then 3.70 gearing, I was getting a bad vibration.
That vibration was the harmonics of the driveshaft flexing from being sent beyond its critical RPM limits.  

No amount of correcting the pinion angles was going to fix it. 

After working with Quick Performance out of Ames, Iowa, MDL, and Spohn the driveshaft was the culprit. With the TKX, I had a new 3.5" driveshaft built with 1330 u-joints. 
Overall I would likely lean towards 1350 sized u-joints but that's a personal preference.   

Now when it comes to the TKX vs TKO, I found I had to swap to a new driveshaft as the lengths had changed. 
I lost my notes at current time and do not have what the correct shaft length should be. If you have done this swap, please note engine, bell house, TKO model number, and then driveshaft length.

Every install should always be verified however on a case-by-case basis to make sure it's the correct length.

Denny's Driveshaft has a great reference listed on their website:" rel="nofollow -

I'm pretty sure I measured using the "B" chart, as this is how the 72-79 cars are set up as the 9" does not use a bolted flange on the axle u-joint." rel="nofollow -

Additional items that come to mind for reference:
For those out their that are converting automatic cars:
MDL Clutch pedal:" rel="nofollow -

Any time I have had to deal with working on the pedal support, I have found it's time and ease of working to just pull the entire dash. 
While it's a couple hours to pull the dash and related parts, its' a lot easier when installing things, or adapting parts without resorting to the old standby of becoming either a contortionist or unbolting the driver's seat and laying on a millennia worth of old fast food fries, dog hair, or the occasional spork that stabs you from the abyss or staring up into the dash only to have rust and more dirt fall into your eyes. 

And honestly with our cars at or past the 50 year mark, I speak from experience checking the condition of the wiring harness isn't always a bad thing to do. 

Hopefully this helps a few folks.

Additional notes:
After discussing with Paul at MDL, I originally went to MDL July of 2023 looking to just rebuild my TR3550/TKO.
Issue was, the TKO was a used transmission, and 4th gear ate itself. 2nd and 3rd gears were toast as well from years of bang shifting. Both mine, and the previous owner. With 4th gear and the slider unobtanium due to TKO parts being no longer made new by Tremec, I bought the TKX. 
I mean, I could have fixed the TKO, but one of the glaring issues wouldn't get fixed and I would have spent $2K on repair of a proverbial time bomb. Dead

I went with the following: 

MD-501-17765" rel="nofollow -

Tremec TKX, Ford, Five Speed
Gear ratio 2.87, 1.89, 1.28, 1, .68od
26 spline input, 31 spline output Shafts Mechanical and Analog Electric speedo drive Torque rated for 600ft/lbs
Tri cone Synchronizers 8,000 RPM shift capability for a smooth fast shift.
Slim line, end loading case 

  • Customer Car information
    Year/Vehicle: '72 Gran Torino 
  • Motor type: 351C / 357 Power level: 400 
  • Crank Balance:
  • Axle ratio: 3.70 
  • Rear tire size: 295/45-18 
  • Current transmission: 3550 
  • Desired transmission: TKX 
  • Drive style or usage: Street Performance/Powertour
  • Speedo drive: Mechanical
  • Console: Yes

Tremec links:
Service manual PDF:" rel="nofollow -    Service Manual
Illustrated Parts List:" rel="nofollow -  Illustrated Parts Lists
General Literature:" rel="nofollow -  General Literature

Andrew:GTS.ORG admin, '72 Q code 5 speed Restomod
Pondering: #99Problems

Posted By: peter.jenerette
Date Posted: 10-February-2024 at 2:18PM
Wow. Great write up. My wallet is screaming at me that this isn't in the budget right now, and if the wallet is screaming, I can't imagine what my program director (aka The Wife) would say...

I'll stick with the top loader for starters, then come back to this thread after I add some elastic to my wallet to hold a little more without screaming. 

Seriously though, this is great.

Pete Jenerette
1972 Gran Torino (H-Code, 4 speed [Converted])
2023 F250 XLT 7.3
2003 Thunderbird

Posted By: Neal
Date Posted: 12-February-2024 at 10:26AM
Great thread, I'm starting my Auto-to-manual swap tomorrow. TKX from American Powertrain with the newly fabbed" rel="nofollow - 72-76 Malwood clutch pedal that includes the hydraulic cylinder all under dash.

Will report as it goes.

1972 Gran Torino Sport

Posted By: pyntre
Date Posted: 12-February-2024 at 3:48PM
Following this !!! 
Very interesting and great information!!
Anyone ever seen a 5 speed 75 Montego ??

Geez would that be fun !!! 

Posted By: Neal
Date Posted: 15-February-2024 at 2:09PM
Malwood Clutch pedal was a clean bolt on, and the reservoir doesn't crowd the brake booster.

I will post" rel="nofollow - more pics in my project thread, plus a rundown of the job here.

1972 Gran Torino Sport

Posted By: pyntre
Date Posted: 15-February-2024 at 2:20PM
You were able to install the new clutch pedal assembly with the entire dash in place then ?!  That’s a huge win !!!!

Posted By: Neal
Date Posted: 16-February-2024 at 4:06AM
Yeah, pretty straightforward, just remove the driver's seat. 

1972 Gran Torino Sport

Posted By: pyntre
Date Posted: 16-February-2024 at 4:18AM
That’s not too bad !!
Get to find all the pennies and French fries 🍟 

Is there a specific shifter you will be using , do you know what that will look like ? Are you running a console or will it just be a rubber boot on the trans hump ?

Posted By: Neal
Date Posted: 16-February-2024 at 4:23AM
Shifter, what came with the Tremec. Edit: check the invoice below, 

Just a rubber boot for now.

1972 Gran Torino Sport

Posted By: pyntre
Date Posted: 16-February-2024 at 4:34AM
Thank you , looking forward to watching your progress with it all !!
Wonder if there would be a shifter / location to retain the bench seat and run this gear ? 

Posted By: Neal
Date Posted: 16-February-2024 at 4:51AM
I think the setup I am using would work for a bench seat as well. I'll definitely know more when we finish. 

I've added the sales invoices from American Powertrain and Malwood. 

1972 Gran Torino Sport

Posted By: pyntre
Date Posted: 16-February-2024 at 8:55AM
Great information!!!

Posted By: Twisted Z
Date Posted: 23-March-2024 at 10:39PM
I did the full conversion from MDL two years ago and I am very happy with it.  Lately I have been having a slight clutch issue and they have been very helpful so far!" rel="nofollow -

Ellis Groo
68 Fairlane 500
Very Fast Chevys

Posted By: Neal
Date Posted: 26-March-2024 at 12:41AM
I love your photo catalog, you have really been through that car. 

1972 Gran Torino Sport

Posted By: Eliteman76
Date Posted: 26-March-2024 at 4:14PM
I spoke with Ross at Malwood. I wanted to just ask a few questions, mainly about the hydraulic release bearing. One nice feature after discussing is the ease of bleeding air from the system. 

Interesting to not Ross and his wife were the ones that actually started Quicktime Bell Housings. 
They have a lot of time investing into things. 

I have a few things I will update as well on the original post relating to the factory spring assist / pedal stop from 4 speed cars.

Andrew:GTS.ORG admin, '72 Q code 5 speed Restomod
Pondering: #99Problems

Posted By: Eliteman76
Date Posted: 26-March-2024 at 4:18PM
Doing a quick addition of Neal's Malwood Hydraulic Clutch Pedal install:

Andrew:GTS.ORG admin, '72 Q code 5 speed Restomod
Pondering: #99Problems

Posted By: Neal
Date Posted: 03-April-2024 at 10:01AM
Ride video" rel="nofollow -

1972 Gran Torino Sport

Posted By: pyntre
Date Posted: 03-April-2024 at 10:10AM
Great video and congratulations on getting it done !!! 
Looks like a lot of fun rowing through the gears !!

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