The Stovebolt Site Forums The Shop Area Driveline My new T5 tranny!

I just finished installing a T5 five speed transmission and all I can say is wow. I never would have tried the swap without all the great advice on Stovebolt. Lugnutz65 has a particularly helpful step by step guide. Thanks guys! http://lugnutz65chevystepside.weebly.com/t5-info-page.html

Tom Langdon put it together and gave me a 0.63 final gear. This works great in my 3600. I think it came out of a 1983 Camaro V8 but he may have used a different tailpiece. The shifter now emerges from the floor about three inches closer to the seat. Tom recommended I find a 10.5” Valeo clutch. I had to buy a kit with a pressure plate to get the clutch disk but the new throughout bearing was too small for my clutch fork so I ended up reusing my old pressure plate and throughout bearing.

I've only got average skills but the install was pretty straightforward. The bellhousing stays on while swapping the clutch so that was a pain but not difficult. I bought a transmission jack at Harbor Freight for $80 after the 20% discount. I only needed it to go up and down twice so I took a gamble! It worked great and made the job much easier and safer.

The driveshaft needed to be shortened and mine was a two-piece. Rather than have two slip joints I had one long driveshaft made up so that got me down to one slip joint. I also made up a tranny support. I don’t know if the original tranny was supposed to have one but mine didn’t.

My old synchros were gone in third gear so shifting is now so much easier and the ratios now match modern driving. It’s still an old truck so I’ll avoid highways but at least now I can do an occasional 60 mph on a secondary road. The one thing I do miss is the click sound between gears that the shifter used to make᠁

George

It is not advisable to support the engine/transmission at three points. The T5 should just hang out on its own. Your front mount and the two rear engine mounts are plenty to support the transmission.
The best description of what happens with 3 mounting points I have heard, is that it is like holding a tree branch by the ends and putting your knee in the middle. Its easy to break. Just using your 2 hands on the ends of the limb, not so easy to break.
Carl

Why is there a mount on the transmission, if that's the case?

George,
Does your clutch disc have 14 splines, 10 splines, or 26 splines?

Glad to hear that my BLOG ramblings were helpful.
I hope to write more sections about the T5 in the near future.

In most of these old trucks, the bell housing has a cross member directly beneath it. That bell cross member also serves as the rear engine support. The cast iron factory 3 speed was bolted directly to the bell without any cross member support.

These T5 transmissions didn't have a cross member support beneath the bell. Therefore, the T5 used a cross member at about the midway point of the tail stock.

Using a cross member beneath the T5 isn't needed if you have a cross member beneath the bell.

Here are a few links for folks who want to see more T5 info from my BLOG.

Complete T5 installation from engine to rear axle.

T5 Transmission Jeep Shaft Swap - DIY and skip the adapter plate

T5 Transmission Rebuild - This is a hybrid build using an S10 tail stock and V8 Camaro gears.

Well Joe, the mount on the transmission is from either the s10 or Camaro the trans came from. they had 2 side mounts on the engine and 1 at the trans. Ergo, a three point mount!

My clutch disk is 26 splines and your blog was key to my success - thanks!

George

Ya'll must count different north of the boarder. One on the front of the motor, two on the bell housing(one on each side). That's three. I have to agree with 52Carl, no need for a fourth mount. Chevy never saw a need for it so I doubt that it would be needed.

Ive installed several of these & always put a crossmember & mount under the trans. The old short cast iron trans hung out there just fine. I wouldn't dare hang that long skinny aluminum trans. out by its self. Did you notice how many braces the factory put on that T-5 in the S-10?

Uh oh, looks like I opened a can of worms. Maybe I should have stayed with a less controversial topic like which is better, 9mm or .45? LOL

George

T-5 in a Camaro/S-10, apples.
T-5 in an AD, oranges.
Engine mount arrangements are vastly different.
As far as the 3rd crossmember in an AD, that was for the torque tube ball, not for supporting any transmission weight. One can ascertain that from looking at the frail design of that particular mount/bracket.
Carl

Hi Lugnutz,

Thanks for the great info you have provided to the forum. I am looking to install a Wrold Class T5 behind my GMC 228 using the 10 spline Jeep WC IS. My question is, are there any different parts required if you are mounting the T5 to a GMC bellhousing as opposed to a Chevy truck bellhousing?

Am I right in thinking that it is possibly only the bolt pattern on the flywheel that differs between the 2?

If you have a World Class S10 T5 with a Chevy pattern case (Muncie) then you will need to take special care when swapping it to the Jeep shaft. To my knowledge, there are no more world class Jeep shafts available. You can just use a non-world class Jeep shaft instead, BUT . . . you MUST take out the fiber style synchro ring along with the original S10 shaft and then use a brass style non-world class synchro ring with the non-world class Jeep shaft.
There are so many bell and flywheel combinations that I honestly can't give you any real help. Just measure bore size, bell depth and bolt pattern before you cut the pilot tip or sink a bunch of money into it.
Take photos and document what you do. I can add your info to my website if you want. It will likely help someone else.

Just as a last comment: I think that the year and body style of the vehicle in which a T-5 is installed has more to do with a rear transmission mount than anything else.
My 37 has a front inline engine mount, two bell housing mounts and the original transmission had a "tie down" at the rear that bolted to the cross member at the rear of the original transmission.
The T-5 transmission lays right on top of the original transmission mount that the three speed in my truck was tied to AND there is a mount on the tail of the T-5 I have in my truck. In addition, there is no longer a heavy, stiff torque tube tied to the rear of the transmission and the rear axle which also carried some of the original transmission weight. My T-5 mounts very nicely there.
I totally disagree with the idea of a T-5 hanging off an adapter that is in turn is hanging off of the engine block with a handful of bolts.
If you go this route, be sure to check your bellhousing mounts on a very regular basis for failure due the that extreme cantilevered weight.
Roll under your truck one more time, look at what I'm writing about here. Does that really look OK to you?

After what I found under my truck, I would also advise checking the rear engine support crossmember where it is riveted to the frame- mine was cracked/broken all over the place on BOTH sides!!

The reason for the the original transmission mount located under the torque tube ball was to support the significant downward force caused by the weight of the torque tube and the tension of the rear leaf springs. Neither of these forces will exist once an open drive shaft replaces the torque tube.
There is a school of thought, based in mechanical engineering physics which suggests that supporting the engine/ aluminum transmission at three points (front of engine, rear of engine, and rear of transmission) can lead to failure at the aluminum transmission/bell housing junction.
I have had a T-5 "hanging" off the bell housing of my '49 3100 for 7,000 miles without issue. I frequently pull a sizable single axle trailer, overloaded with parts-for-sale to swap meets, and I do not otherwise baby this truck.
When I first set this truck up with the T-5, I was concerned with the transmission hanging out into space behind the engine. I even rebuilt the torque tube mount and fabricated a third mount for the T-5. After researching the issue, I removed the third rear transmission mount. Sometimes mechanical physics can seem counter-intuitive.
Carl

I stand by my comments: Watch those two bellhousing mounts. Check them regularly.

I suppose all the 55/56/57 Chevy cast iron 3 speeds that just hung out there in space with no rear support had the same problem? I've never seen a loose bellhousing on one of them in nearly 60 years of wrench jockeying.
Jerry

The reason for no need for a rear transmission mount (under either manual transmission) under a 1954 torque-tube transmission was due to a change in design in the 1954 and later frame and rear-engine/clutch-housing frame cross members (pages 49-51).

The Hydra-Matic transmission needed an additional crossmember and rear mount, but the 3-speed and much heavier S420 4-speed no longer needed a rear transmission mount/cross-member.

Many 48-53 owners probably get by with no problems running with no rear transmission cross-member, but GM thought is was required.

The car frame had no rear transmission cross-member or transmission mount, even with the Powerglide RPO-313.

The Hydramatic transmission length is 8" inches longer and its torque tube is 8" inches shorter.
More weight is hanging farther out pass the flywheel housing.
Hence the need for the a rear transmissions tail housing cross-member. Picture: 1954 Chevrolet 1/2 ton H-M rear tail housing crossmember

The re-engineering of the cross-member under the flywheel housing in 1954 eliminated the need
for a rear transmissions tail housing cross-member on the 3 and 4 speed transmissions. Picture: 1954 Chevrolet 1/2 ton rear of 4 speed trans.
Both 3 and 4 speed transmission are the same length so are the length of their torque tubes. TT Measurements

There was a company that made some kind of support Picture 1 , Picture 2, Picture 3, Picture 4
that clamped around the tail of the U-Joint ball housing and the torque tube.
Its soul purpose was to prevent the torque tube from drooping downward.
The reason for the torque tube droop is probably coming from the downward force when applying the brakes. Picture 5
Here is a GM film Strip (Starts on picture 35), about repairing the ball housing and the end of the torque tube.
Because of down force wearing them out.

When i did my t5 swap i also installed a cross member. Jumped thru hoops to get it to fit proper and install correctly with all the brake stuff in that area. I still have it installed and have had no issues yet, I just have not been under the truck in a while so i have not taken it off.

I also came to the conclusion that is can cause more damage than good. because of the twisting in these frames. It will be taken off come spring time and i do my normal maintenance routine.

Great point on the frame twist, wolfcub. THAT is what will break the aluminum transmission.

I am reading the comments posted but staying out of the argument. However, here is some more info for thought.

The original S10 T5 tail rubber support is shown HERE (center of picture).

HERE I am holding it.
The threaded end goes into the S10 crossmember and the 2 holes on the plate end bolt to the bottom of the S10 tail housing.

The bushing seems to be designed to allow some torsion (either from the frame twisting or from the drivetrain torque. A single bolt is molded into the rubber. The design would allow the rubber to rock a little side to side.

I'm not arguing FOR or AGAINST a cross member. Just supplying a little info, that's all.

If you are convinced that a cross member is what you want, then by all means use a rubber mount like in the photo.

THIS ARTICLE printed in Hot Rod Magazine in 2012 shows a cross member support that in my opinion is engineered COMPLETELY WRONG. See photos #23 and #24. They have the tail housing bolted to a 2 bolt style rubber bushing which will not allow sufficient movement with torsional forces applied. A single bolt design that is molded into the rubber (like the one from my photobucket page) would allow movement and yet add support.

S10s didn't use the front engine and the bell housing engine mounts (like the inline six ADs). S10s require the rear transmission mounts so that there is support at two points (side engine mounts and rear transmission mount).
Not trying to drag you into this colorful debate, Lugzy.
(Yes I am. )
Carl

You didn't ask me if I use a transmission support on my truck. Chuckle chuckle!

Some s 10 t5s came with 2 rods that bolted to the 2 holes where a rear mount would be and went down to the 2 lower bolts used to bolt the trans to the bell housing which supported the tail housing with out the extra cross member issue.
I suspect if using a 2 piece drift shaft with a hanger bearing a short distance behind the trans as opposed to a 1 piece shaft it might eliminate a little of the weight that needs to be supported.
To date I've put 3,500 miles on mine without a 3rd cross member with out any issues