The Stovebolt Site Forums The Shop Area Driveline My T5 conversion

Well the truck is now a 5 speed daily driver!

First of all, a huge thanks to lugnutz for his "How To" postings.

My install was pretty much text book easy. I shortened the input shaft on my 1352-146 tranny (from a 1985 S10 with v6) .5 inch. I made the input shaft bearing retainer the same length as the stock one on the SM420 tranny, had to shorten it I believe 1.5 inches (going from memory if wrong I'll let you know).

I used a RockAuto, 11" clutch disk for a 1988 Astro van, (less than $50.) . It was necessary to lengthen the splines on the input shaft (Dewalt angle grinder and cutting wheel) by about .5".

Used original low mileage pressure plate. I cleaned the fly wheel and pressure plate with 80 grit sandpaper.

Drilled out tanny case mounting holes to .5", used stock bolts in top holes and two new bottom bolts 2" long.

Welded a Model T shifter (picked up at the Petit Jean swap meet last fall) to the S10 shifter. I didn't want to destroy the original shifter.

Did away with the original two piece driveshaft and had a new 3.5" driveshaft made, 1350 series u-joint on rear, stock S10 3R on front along with the stock S10 front yoke.

Built a transmission crossmember from 2"x.25" flat stock bent at 45's and boxed with 3/16th" X .75" flat stock. Used stock S10 mount. (note the torque multiplication devise that helped drill the mounting bolt holes in the frame).

That's about it,,,no big issues on the install. But now for the problem...I bought a junk T5 for $100 and the input shaft bearing was totally gone, just pieces in the bottom of the tranny. I had a new bearing installed and gave the inside of the case several diesel and gasoline wash jobs along with a couple of high pressure water clean outs. I feel sure I got all the old bearing and race material out.

(I did drive it about 5 miles after the conversion and then drained the ATF fluid to remove any remaining junk, I refilled with Harley Davison Synthetic 20W50 with a bit of Lucas Stablizer in an effort to quieten things down.)

A very close inspection indicated no wear problems on any of the gears, but due to my inexperience I didn't remove the mainshaft, just reassembled with new input roller bearings and input shaft bearing along with a new flat bearing. I was not able to use a inputshaft spacer (under the little flat bearing) since I had zero endplay with no spacer.

Now, the tranny whines in every gear including neutral. Push clutch in and all's well.

I've put around 500 miles on the conversion and the junk T5 shifts great, no jumping out of gear or anything it's just noisy.

I'd appreciate any comments and thoughts. I have been quietly looking for another transmission, the perfect one will have a 4.0 first gear and a .72 or ,68 5th gear, but man I can't stand 7 or $800 that I'm seeing.

Ron

Added in edit, just discovered I can't post images. Lugnutz, can you share the ones I sent your way?

Thanks!

I didn't use a transmission crossmember on my '50 1/2 ton. I have read that anchoring the engine/transmission at more than 2 points (front and rear engine mounts on an inline six) can lead to undue stress to the transmission. It has been described as similar to breaking a tree limb using 2 hands with your knee in the middle.
As far as your transmission woes, I would start combing the junkyards for another T-5. The ones behind a 4 cylinder in an S10 are plenty strong enough for your application, and the 1 through 5 gears are spaced real nice for the inline six. I could not be happier with mine. Lugnutz was my mentor as well.
Carl

52Carl said; " It has been described as similar to breaking a tree limb using 2 hands with your knee in the middle."

Carl, interesting...I really debated the need for a mount. I do believe the aluminum is plenty strong , guess I was hoping to headoff any issues from long term Truck type usage. Time to rethink that decision.

Thanks, Ron

Now you're making me think T5 again. It is funny watching the faces when I shift the old three in the tree though.
John

Moparguy,
Here are the pics you sent me.

Crossmember installation

Fabrication of crossmember

Shifter mockup

Shifter welded

Shifter fabrication done.

Try this. Rev the engine while in neutral with foot off the clutch and just sitting still in the driveway. That spins the IS and the countershaft but not the main shaft. If it whines then it has to be the IS bearing or one of the countershaft bearings. The bearings where the main shaft meets the IS might possibly whine but I doubt it unless there is severe binding.

Then try coasting at 40MPH with the tranny in neutral and the clutch pedal in. If it whines then it must be the rear main shaft bearing.

If it only whines while in gear under load then I'd say it's coming from the countershaft bearings.

Lugnutz, thanks for the input. I've driving a couple hundred miles in the last two days running errands and decided it's time to pick up a bearing kit.

In neutral, it whines. At 40 in neutral with clutch in, really too much noise to tell. I've decided it's definitely at its loudest under load in 5th.

Any tips on a kit that includes the necessary bearings? I've already replaced the input shaft bearings, and made use of a small item kit off ebay that include shift fork pads, two flat bearings, the 15 I/S roller bearings along with several other miscellaneous items.

My first drive after i rebuilt my t5 was very whiny. It was the shimming of the input shaft bearing. After i took it back out of the truck and adjusted it it went almost silent. Also be sure to install a boot and cover as much as the hole in the floor that helps lots with transmission noise. As soon as my boot went on with the carpet and sound padding it went away 100%

I was also wondering about the third mounting location. Has anyone actually cracked a trans housing yet?

My third mount is fine. It sits right where my original stock third mount was. Mine is sitting on lots of rubber. It can move around pretty easy. It just seemed right to have a mount there. There is allot of weight hanging out there without at least a little support.

The New Process 5-speed in Fire Engine just hangs on the bell housing and it weighs about 135 pounds, not counting the PTO drive unit that's mounted on the side of the trans.

Mike B

Pulled the T5 today and looked inside, found inputshaft (IPS) issues. As mentioned previously this was a very cheap junked out T5 with a totally destroyed IPS bearing with everything else looking good. I had a new bearing pressed on. On reassembly after a (I believed good case/parts cleaning) I wasn't able to get any IPS freeplay since something was spacing things out besides the shims I'd removed (input shaft bearing spacer shims).

Well today I found many thou of freeplay and the IPS gear knife edged.

So, ordered a new shaft tonight...will clean, reassemble and set IPS endplay ASAP and see what I've got.

To complete the previous post...installed the new IPS last weekend, tranny was still pretty noisy on first drive. However after driving about 75 miles it's noticeably quiter. Almost no whine in 1st thru 4th. 5th is still objectionably noisy, but much better and getting better with miles (it seems).

My hope is that with time the new gear will wear in, matching it's neighbors and be acceptable.

Actually, a small amount of gear noise does seem to be in character with a 51 3/4 ton flat bed truck

RR