The Stovebolt Site Forums The Shop Area Driveline T5 Conversion

OK, now I've run into a problem. I bought a rebuilt T5 that was said to be fully modified to bolt right into my 1942 3/4 ton. When I tried to install it yesterday, the bolt holes did not align with the bell housing. I know the 3/4 ton used a different bell housing than the 1/2 ton because of the larger clutch assembly. But I wasn't aware the trans bolt pattern was different. Apparently, I will need either an adapter plate, or an unmodified T5, or both, to get a T5 into my 3/4 ton. Has anyone put a T5 into a 41-46 3/4 ton? If so, what did you use to make the conversion? I would really like to keep my OE bell housing & pedals. Any help or advice will be appreciated.

Lugnutz, this ones for you.

Ghost Rider, T5's were used in a lot of vehicles and not all are easily converted to our trucks. Do you know what your T5 was originally in and what year? Or better, does it has the metal tag (about 1"x3") or sticker with a 1352-??? number.

I trust our T5 guru, lugnutz will be along soon to provide proper guidance.

RonR

Thanks guys. The T5 is a 1983 version with the mechanical speedo drive. The 1352 number is 043, from an S10 v6.

Tom, good score on getting a hen's tooth of a transmission. Those particular T5's are getting scarce. One thing that comes to mind....have the metric bolt holes on the T5 transmission to bell housing been drilled out (from 12mm to 1/2" ??) so the Chevy bell housing bolts will work?

OK that's all I know now, for the experts to wade in.

RonR

Yeah, I drilled the ears out before I attempted to install the trans. I think it's mostly that the bolt pattern is actually different. The spread between the upper mount holes is about 1 inch wider than the bell housing. I have no doubt that this could be corrected with an adapter plate. However, if I go that route, this "modified" transmission will have to be modified again. That's because they shortened the input shaft & bearing retainer to fit without an adapter plate. Agree that this trans was a good find, but I now have new challenges to make it work. Probably changes that no one else has experienced at this point. Thanks again for your help and advice.

BTW, this 42 3/4 ton is bone stock (except for the motor) and has the OE Muncie 4 speed. Guess not all Muncie 4 speeds used the same bolt pattern. I do have a later 6 cyl truck bell housing (GM 3702831) that does fit the T5 exactly. Except that would probably necessitate a change in clutch, pressure plate, motor mounts & pedals. Something I was hoping to avoid.

Tom, I put a T5 with mechanical speedo in my 1941 3/4 ton about 10-12 yrs ago. I used an adapter plate made by Buffalo Enterprises with the standard T5 input shaft. I sent him my input shaft so he could machine the plate to fit. The splines on the clutch plate are different also. I used an 11 inch clutch made for an Astro Van with the original pressure plate. I had a few inches added to the drive shaft and the front u-joint changed to match the T5. Everything bolted in easily. I made a couple brackets from angle iron to mount the hand brake lever to the T5. This way no changes are needed to the clutch and brake pedals. You could probably swap the modified input shaft with someone wanting one for an AD truck.

'42 bell housings have a different bolt pattern than later that have a GM bolt pattern like your T-5, unless it is a Ford bolt pattern. All that matters is retainer diameter-they both must match; input shaft stickout; and bolt pattern. '42 or early bellhousings may be easily drilled out if other dimensions match. Perch the trans on top of the bellhousing, use a transfer punch to locate mount holes in bellhousing, take part, drill and tap holes marked in bellhousing.

Ed

Ghost Rider,
If you use an adapter plate, then you are correct to assume that your present T5 input shaft is too short (assuming the pilot tip was trimmed).
The easy solution will likely be

1. Add an adapter plate so you can keep the original bell.
2. Replace the current T5 input shaft with a new Jeep input shaft (that doesn't have the pilot tip cut shorter).
3. Replace the input shaft bearing retainer with the longer S10 version (I'm assuming your original one has been shortened).
4. If needed, install an extended pilot bushing (available from Summit Racing).

I just got off the phone with Dave Farwell. His website LINK IS HERE.
He sells an adapter plate (item T5-4316) that will allow your T5 to bolt to your factory bell. It sells for $169. I didn't ask about postage.

His contact info is
330-322-3102 or email at [email protected]

A new T5 10 spline input shaft with 21 gear teeth is about $70 shipped to your door (I buy mine from eBay vendors). I assume you have a 10 spline clutch.

BEFORE you spend any money. You need to make some measurements.
Measure your FACTORY transmission for -
1. Distance from the pilot tip to the front of the case.
2. The LENGTH of splined section of the FACTORY input shaft.
3. The Longest DISTANCE of the splined section of the FACTORY input shaft to the front of the FACTORY tranny case.

The reason for all this measuring is -
1. The adapter plate pulls the input shaft splines 5/8" away from the clutch disc. We need to make sure the T5 splines will still engage the clutch disc. Dave Farwell will probably confirm that this is not a problem, otherwise his adapter plate wouldn't work.
2. After you install the new input shaft, your T5 pilot tip will need to be the same distance from the front of the case PLUS 5/8" (thickness of the plate). So trimming the pilot tip may not be necessary. If the distance is too short, Dave Farwell mentioned an extended pilot bushing that will solve that problem.
3. The input shaft bearing retainer sleeve will need to be the same length as the FACTORY sleeve PLUS 5/8".

If you have a different bell -
- that will bolt to your engine
- that has a Muncie pattern that matches your T5
- that will work allow you to keep your current clutch mechanism
then that would be a logical choice as well (but less original).

Give Dave Farwell a call. You will not find a more pleasant person to deal with.

Jay

Jay

Thanks for your hard work. This certainly looks like it will solve myT5 compatibility problems. I've sent Dave an email, and I'll follow up with him tomorrow. I'll also complete all of the measurements you suggested before ordering any parts. Sincerely grateful for your kind expertise and assistance. Thanks also to Harold and Ed for their help. Best regards,

Tom

Jay

Thanks once again for your help. Below are the measurements you recommended. I've contacted Dave and I'll most likely be buying his adapter plate, and a new input shaft.


The Factory Trans (42 Muncie 4spd) is;

1 - Pilot tip to front of factory trans case = 6 3/4

2 - Length of splined section of the factory input shaft = 2 3/8

3 - Longest distance of the splines section of the factory input shaft to the front of the factory trans case = 5 1/2

So, if I'm figuring correctly, using a 5/8 inch adapter, I need;

1 - An input shaft that will be 7 3/8 overall from the front of the trans case to the tip of the pilot

2 - with splined section that is at least 2 3/8

3 - and has a distance from the front of the splined section, to the trans case of 6 1/8

4 - with 10 splines

I also got a couple measurements Dave recommended;

1 - Front of clutch disk spline hub to Bell housing trans mounting face = 5 7/8

2 - T5 mounting face to front of splines - 5 7/8


If I did this wrong, just holler at me..., slap the side of my head, and set me straight.

Not sure which T5 input shaft meets those measurements more closely (most sellers don't provide engineering drawings) but, I'm sure open to suggestions. Also, the bearing retainers on the Muncie, and another NOS retainer I have lying around here, are 3 1/8 from trans face to retainer tip. The modified bearing retainer on the T5 that I bought is actually closer to 3 1/4. So it looks like I'm gonna have to find one closer to 3 3/4 (+5/8). Check me on all of these figures, and if possible please provide data on any recommended parts that may fill the bill. Thanks once again. Don't know what I be doing if it weren't for this site. All the best,

Tom

I am seeing this late in the day and my mind is tired, so give me another day to digest it.

I have a new Jeep shaft in my shop and I'll make some measurements.
My eyes are falling shut. It's late. At least I finished the ball joint installation on my 1965 tonight. It went well.
Jay

Jay

Thanks. Ordered the adapter plate from Dave this morning. Pat at Anaheim Gear is sending me a 10 spline Jeep input shaft, bearing, and modified bearing retainer. I should be able to change the input shaft & retainer, and bolt the trans to my truck.
Glad to hear your ball joint replacements went smoothly. All the best,

Tom

So the adapter plate and Jeep shaft swap will likely work very well.

Here are some of my measurements tonight.
All of this pertains to an unmodified Jeep 10 spline input shaft that's ALREADY INSTALLED in a T5.

The pilot tip is 7 + 1/8" from the front of the case.
The pilot tip is 1.5" long.
The input shaft bearing retainer sleeve extends 4.5" from the front of the case. (An S10 version that has NOT been shortened)
The Jeep shaft splined section is 2 + 3/8". (same as your factory shaft splines)

So your calculations seem correct. You will need the pilot tip to be 7 + 3/8" from the front of the case. The Jeep shaft is 1/4" too short but it may still end up inside the pilot bushing. Using an extended bushing might be a good idea.

So the Jeep splines extend out 5 + 5/8" from the front of the T5 case but when you use the adapter plate, they will only extend 5" beyond the front of the plate. Your factory splines extend 5.5". So we're 1/2" short there, but you might be OK. It all depends how much of the Jeep splines actually fit inside the clutch disc hub once installed.

The S10 bearing retainer should be plenty long enough. It will still mount to the T5 case and then sit inside a recessed area in the adapter plate. It will thus lose 5/8" of functional length. You calculated 3 + 3/4" and I'd save that cut for last. (4.5" minus 5/8" = 3 + 7/8" - so it is plenty long enough but may only need a 3/4" trim).

Jay

Thanks for taking the time to help me out with this issue. It is sincerely appreciated.

I've ordered the adapter plate from Dave Farwell. Hopefully it will be here by tomorrow. Once I've installed that, I can take additional measurements to confirm the required length of the bearing retainer for my application. I've asked Pat at Anaheim gear to trim the new S10 bearing retainer by 1/4 inch, as recommended by Dave. Since I'm not certain of the exact length, I thought it best to trim as little as possible, as I can always cut it down more, if necessary.


I'll post again after I've gotten the plate installed and the T5 modified with the Jeep input shaft. Thanks to all that have helped me get this right.

Tom

Got the T5 installed today. I'll post photos tomorrow.

OK, I've installed the T5 into my 1942 3/4 ton pickup. The process went quite smoothly overall. The only thing I ran into that caused a delay was the adapter plate. Appears that the plate was cut to exactly the same spec as the opening in my OE 1942 3/4 ton bell housing. It did fit snugly into the opening however, the face of the plate did not seat totally flush with the bell. It left a gap between the bell and the adapter that was about 1/8 to 1/16 inch. I removed the adapter plate, and my son modified the mating surface very slightly, to allow the adapter to sit flush. Apparently, the machining at the adapter plate ring which rests inside the bell housing opening was slightly rounded. That small rounding was enough to prevent the plate from mating flush with the bell. My son took a file and squared up that edge. After that, the adapter fit solidly flush with the bell. Once the adapter plate was flush and square with the bell, the T5 slid right in and aligned perfectly. Driveshaft should be ready by Wed. I'll update again when she's on the road.

I now have a running and driving 1942 3/4 ton, with a nicely operating T5 trans. Thanks to all who so generously helped me through this swap. All seems good. I only need to take her for a good long run to check every phase of operation. I do have a problem that is challenging me, and that is my speedo driven gear selection. I went through the calculator and I got a recommendation of a 24 tooth gear. I wasn't able to find a 24 tooth gear, so I installed a 22 tooth, as it was available. My truck has a 4.55 OE 1942 differential. I'm running 600-15, 6 ply tires, that are 29.4 inches in OA diameter. The T5 I installed (1352 042) has the red drive gear in the tail housing. Today, I drove the truck through one of those radar devices the police put out along the road. At an indicated speed of about 50 MPH, the radar showed me 37 @ MPH. Clearly, I do not have the right drive and driven gear combination for my set up. I did buy a set of drive gears with different tooth counts so maybe if I replace the 22 tooth with a driven gear that has fewer teeth, I can get a more accurate speedo indication. Any advice is appreciated.

The T5 has only 2 options for the drive gear, blue or red. Blue has 7 teeth and red has 9. Use the drive and driven gear calculator to find the combo that will work best using available driven gears.
In your situation, switching to the blue drive gear is probably best.

For some folks, using a ratio adapter might work. I have several that I pulled off of older T5s. IIRC the adapter is a 1 to 0.72 ratio change, so I think it would slow down the speedo.
Fewer teeth on the drive gear = faster speedo reading.
Fewer teeth on driven gear = faster speedo reading.

More info LINK HERE

Jay

Awesome project. Can you post a couple pics of the truck and trans in place?

Jay

Thanks. I'll look at the options. Best Regards,

Tom

Mark

Hi. I've tried to post photos here several times. I always get the note that the file is too large. I'll look into this further.

Tom

Go into yor photo editor and open the picture file, choose "Edit", make the file size smaller ( the last picture I posted on this site was 584 pixels wide, 438 pixels high, and had a resolution of 200PPI and it loaded just fine); then choose "save as" in the file menu and save it to your desktop temporarily and post that picture. Using save as instead of save ensures that your original picture is unchanged and still in it's original locatio........

I use this. It's easy.
https://www.irfanview.com/

OK. Followed your advice and resized the photos. Still will not allow me to copy & paste into this posting. Needless to say, I don't do much with photos online.

Tom, have you read the Image Posting Policy in the left margin of every page? If you have, I understand.

Test to see if I got this right. Sent as attachments. Still uncertain as to how to embed the image in the posting.

[img]http://[/img]

A bit better photo of the truck. She is a driver, not a show truck. Yet..., wherever I park her, it somehow becomes a truck show.

I'm very happy with the T5 swap, and I recommend this to anyone who is considering upgrading from their OE 1930s - 1940s Muncie 4 speed. It is possible to retain your original clutch, bell housing, pedals, and parking brake, while upgrading your 41-46 Art deco 3/4 ton truck to a modern T5 transmission.

The major changes include an adapter plate (5/8 inch thick) for the early Chevy bell housings (Vintage Metalworks, OH), a good S10 T5 transmission (got mine from Anaheim Gear), a 10 spline jeep T5 input shaft (Anaheim Gear), an OE S10 T5 bearing retainer cut down by 1/4 inch (Anaheim Gear), and a good T5 shifter (I used a Hurst but you can modify an OE T5 shifter). With these components, the entire project bolts together. The only modifications to the truck itself was the floor cut outs. I bought a reproduction floor off ebay, and cut that, so I would not destroy an original part. Basically, I now have every component necessary to restore this truck to it's original configuration sitting on the shelf, should I ever decide that an original truck is more desirable. The only outright fabrication involved was the creation of a bracket to mount the OE hand brake to the T5, and cutting the holes in the new floor.

If I had one observation at this point it would be that the T5 seems as though it would be happier if I were running a 3.90 or 4.11, rather than my stock 4.55 differential. But that's another thread.

Once again, my thanks to everyone that has helped me through this swap by answering my questions, and providing their expertise and advice. I have thoroughly enjoyed the project, and your help. Stovebolters are the best.

Tom

Nice truck and nice job on the T5.
I have a Hurst shifter base that is similar to yours. Found it at the salvage yard. It was in a Camaro.

Very cool truck!

Thanks Jay. And thanks for your invaluable guidance and expertise. I couldn't have done it without you guys. All the best.