I have been chasing a vibration in my car since I installed a T-5 trans on my 292. (54 Ford car) Found out that it appears that the input shaft needed to be shortened or it touches the end of the crank. I used a Mummert adapter to install the T-5 on the bell housing. Question is, how much to cut off the input shaft. The thrust bearing is worn pretty good so I am fairly certain the input shaft is hitting. How much do I shave off to get adequate clearance? Can't find a dimension anywhere that I have looked. We believe the trans is out of an '87 Mustang V-8.
Thanks!

If the input shaft was hitting the bottom of the crank, it would spin anytime the engine was running, and you couldn't shift into gear. Check the U joints and drive shaft for being warped, also if the trans has many miles, check the output or tail housing bushing.

If you actually got it mounted, then it would just barely be touching, if it is touching at all.  You should see wear where it was touching.  If that is the case, probably 1/16" and bevel the edge and I think you will be ok.  When I installed mine, I just pushed the transmission until it touched the crank and used the measurement between the trans case and bellhousing to determine how much to cut off.
You also potentially changed drive line angles and probably had the drive shaft shortened, and those can cause problems if done incorrectly.
Yet another possibility could be that the transmission needs a rebuild.
The transmission will have a tag on it, similar to a rear end, which can be used to id it.  If that tag is missing, then there's not really a way to tell what it is



Lawrenceville, GA

I should have mentioned that the vibration is present between 2000rpm and roughly 5000rpm - doesn't matter if the trans is in gear, clutch in or out, or in neutral. car moving or standing still. It shouldn't  be the driveshaft or something inside the trans, except maybe the input shaft, which I will check once I get it out of the car again. The motor had a new thrust bearing installed before the trans went in and in the time since the trans went in and trying to figure this out, we noticed that the thrust bearing was worn - that and reading on here several places about needing to cut the input shaft back, has led me to think I should take a look at cutting mine back. If it is touching, it must be slight as the trans did bolt up OK.

Checked all plugs and wires, firing order, and have gone through the Edelbrock 500cfm carb I installed to try and rule that out. We're now focusing on the trans as the next possibility. This motor ran fine and did not vibrate until I made a couple upgrades - installed the T-5, installed a Mummert Blue Thunder 4bbl intake, and the Edelbrock carb. Not sure related but it also seems to smoke more than it used to through the breather tube - working from easiest to hardest to find the fix.

Thanks.

I used the same method Charlie did, but since the motor was out, I checked the depth with clay before I installed the pilot bearing. In my case, I think it was closer to 1/8. If yours was that tight, I doubt it would shift

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

It shifts fine. The clutch pedal engagement is pretty high (no play when pushing clutch pedal before it releases the clutch). Other than that, trans seems to be working fine. Shifts good in all gears and reverse. Maybe I'm on the wrong path.

You need to adjust the clutch so you have about 1inch of free play, running that tight will make the clutch slip, as well as wear the throw out bearing out. Adjusting that might even help with the vibration.

I've converted to T-5 in both my 57 bird and 56 Effie... unless Mummert (John) changed his adapter design somehow, it's weird to me how you got an un-shortened input shaft to bolt up "OK" , meaning no gap at the mating surfaces or bent/broken flange ears... 1/16" to 1/8" is a lot, and as aforementioned, rotation engagement would be nearly constant.

But anyway, from your posts, you've got clutch function, the vibration occurs at 2000+ rpm whether in gear rolling or in neutral standing still, the thrust bearing appears worn (how did you determine this, btw?), the pedal engagement is "pretty high", and now the engine is showing some sign of "stress" via greater smoke from the breather.

Noobie guessing here, but is it possible that bolting up an un-shortened input shaft forced the natural crank end play (which gets more generous as engine ages) to a sufficient distance to operate, but has with some use create wear harmonics noticeable at revs higher than idle?  Or, since vibration is a symptom of harmonics due to imbalance, is it possible that the Flywheel, clutch disk or pressure are imbalanced due to abnormal wear due to forcing an un-shortened input shaft into place?

I think you'll find the answers once you crack the engine and tranny apart.   I doubt it's tranny failure per se, or anything aft from there. Just curious, does it leak oil unusually from the flywheel cover area?

Cheers... Brian


Cylinder Index = 84

Current Experiment = `57 Tbird, Grand Rapids, Michigan

I had the car into a shop a couple years ago (I haven't driven it much since then - just test runs when I try something else) to have the flywheel/clutch assembly balanced. When it was apart he checked the crankshaft end-play and found it to be a little more than normal - not too bad but more than normal. So he did a little investigating and found the thrust bearing worn. He had the trans out of the car and he didn't notice anything odd about how the trans was installed our any clearance issues. My guess is that the input shaft is right up against the end of the crank but not pushing hard on it. Maybe just enough to cause the two to be touching. I did not put the trans in, I had a hot rod shop put it in that has since gone under.

I don't see any unusual leaking under the car - just the drips I get from the rear main seal. Otherwise, nothing more than that. Starts and runs great, just vibrates.
Thanks.