The Stovebolt Site Forums The Shop Area Driveline engine and transmission mounts

Hi all. I bought a 55.1 3100 that is missing the OG motor and trans. I picked up a '57 235 out of a truck with a 4spd top loader trans . My plan is to put a T5 on it but there are a few issues I could use some advice about. The motor has side mounts now but I plan on drilling it for a front mount and use the bell housing mounts on the rear for a 3 point mount. Will this work ? Will I need a separate trans mount or can the T5 just hang in space ? Will the bellhousing fit on the crossmember ? The crossmember still has the rubber mounts in place. Thanks

Your plan sounds good. The bell housing will fit the the 55-1 frame. Some guys hang the t-5 out in the air but I like to put a crossmember in it with a rear mount. That skinny alum housing doesn't look right without it. The factory puts about 4 braces on them.
George

Let the T-5 hang free.
A 55.1 with an original 4 speed hangs free. It probably weighs 2-3 times more than an aluminum T-5.

Let it hang. I've had an nv4500 hanging off of the back of my bellhousing for 15 years or so with no issue. Medium duty trucks have 300-400lb transmissions hanging off of their bellhousings

?
Would that be on a 1953 or earlier Stovebolt 1/2 or 3/4 ton truck?

[quote=Let it hang.
I was saying my preference. I have done several t-5 swaps & always put a mount under them. Those examples have big husky cast iron housings.

I'm with Wrenchbender here.

We can all agree that the cast iron bellhousing is quite capable of carrying the load of a T5 transmission. The problem you'll run into is the thin cast aluminum housing on the T5 flexing during use and dramatically shortening it's service life.

Put the crossmember and rear mount in.

Steve

I did build a crossmember for my T5. It's host 3600 does truck work at times and I just felt better with the transmission being supported. With over 10,000 miles of history, no issues.

Now the above said, has anyone had a problem in long term use (as in many thousands of miles) running a T5 WITHOUT a rear mount?

RonR

Thanks for all the feedback guys :-) I think I'll go ahead and put a tailshft mount under it just for insurance . Wouldn't want to have the tranny bust at 150 mph ;-)

If one is worried about snapping a T-5 under load, one should consider that securing an engine/transmission combination at three points for its entire length can be more hazardous, than letting it hang behind bell housing.
An analogy would be: Put a stick in your hands and try to break it. Now introduce your knee at the center point of it. The stick will almost break itself.
Adding the third mounting point for your 235/T-5 is "the knee."

Will one ever break a T-5 with the third mounting point at the tail housing? Probably not.
Will one ever break a T-5 with it hanging free? Probably not.
We drive our trucks like we're blouse-wearing poodle walkers. We don't even break a tire loose upon takeoff.
All I know for certain is that not adding a third crossmember mount is one step less I have a need to mess with.

I'm taking that as a challenge. When I get mine on the road, I'm going to see if I can lay down a black stripe on the road. It may be only 6" long, but hey.
I do have 3 drag racing trophies after all.

I see some T5s with weights bolted to the tail housings . I assume it's purpose is to damp harmonic vibrations ? Are they needed on these conversions ?

There's nothing wrong with adding another crossmember. It will strengthen the frame some more, but you are just doing extra work. A t5 isn't going to crack just because you hung it off of the bellhousing you have pictured. That's how a lot of people have done this conversion.

I have over 20,000 miles on my 49 3600 with a T5 and no rear transmission mount and no issues. A lot of those miles are pulling a 2,000 lb camper. I've also installed T5s in trucks for others without the rear mount and they also get used for towing without issues.

I run a t5 in a one ton powered by a 261 , In the last 5 years I've managed about 25,ooo miles with the trans. hanging free , with no issues . That being said it has a hanger bearing about a foot behind the trans which might alleviate some of the weight hanging of the back end .
An option might be to run a support from the trans mount to the bellhousing as done on some of the S 10's

John