Any Ideas on Trans Problem

[Andy CobraII]

I read this forum often, it has provided me with a wealth of information
in my long love/hate journey restoring my cobra ii. just wanted to say
thanks and suck up before I get to my problem.

I have been in the process of converting an automatic to manual.
I have a stock engine and went with a 4 cylinder t-5 setup. I bought
cheap from this websites classifieds section and it appered to be in good
shape. It was from 89 turbo and included bell. I put this behind my v-8.
Had a local shop rebalance flywheel and press me a smaller pilot bearing.
Also, shortened my driveshaft. Just to clarify- it came with a bell for a v-8
setup. I re-used my auto starter. Everything fit fine, just tight.

I recently got engine back together and solved some electrical issues.
In neutral, engine purrrrrrrrrrs. revs high, no imbalance kinds of shaking.
I put the rear end up on blocks to test tranny. 1st gear ok, starting in
2nd as I increase RPM's, horrible tranny shaking thunking sounds. same with
3rd and 4th.

Now that I have a load on engine, is this an imbalance problem with flywheel.
Maybe the shop got it wrong? Could this be a pilot bearing issue? Or did I buy
a cheap tranny with a bent input shaft? Any ideas would be appreciated. I plan on pulling everything aprt anyway, just wondered if I was missing something.

thanks
andy

 

[dmoody]

It is definitely not the flywheel or it would shake in neutral as well. It sounds like it is either your driveshaft or transmission.

d

 

[Andy CobraII]

d,
I didn't think it was flywheel either. But as soon as you mention
shaking everyone I talk to jumps on the 28oz balance for early v8's
I know it isn't the driveshaft. Hooked up a newer balanced one to make
sure. Discovered that a late model 96+ is the right length for this conversion.
Needs different u-joints though.

 

[Dano78]

Ujoints? I assume they are new too.

There is a considerable difference between the 2.3L T-5 and the V8 T-5. The input shaft, I believe is a little bit longer on the 2.3L T-5. You've got this mounted into a V8 T-5 bellhousing? Are you 100% sure the input shaft is seating into the pilot bushing properly?
I've had similiar vibrations in the MII's RAD tranny (similiar to a T5) especially in 2nd & 3rd gears. What caused that vibration (on more than one occasion) is the front or rear main bearings go out. In the RAD they are cased roller ball with inner and outer race type bearing (sotra like some axle bearings are) and are a major piece of junk. I've found that they are starved of proper lubrication in alot of cases.
Also- make sure the yoke of the driveshaft fits fairly snug into the tailshaft of the tranny. There will be 'slight' play. If it doesn't, that can cause pre-mature wear on the mainshaft assembly and/or rear bearing. Usually there is a brass sleeve pressed in where the yoke would contact the tailshaft housing.

It'd be worth a look.

 

[2muchtime]

I recently got engine back together and solved some electrical issues.
In neutral, engine purrrrrrrrrrs. revs high, no imbalance kinds of shaking.
I put the rear end up on blocks to test tranny. 1st gear ok, starting in
2nd as I increase RPM's, horrible tranny shaking thunking sounds. same with
3rd and 4th.
thanks
andy

i wouldnt tear anything apart until its confirmed with an actual road test..
how does it act goin down the road??
the vibration could even be a bad tire.
a wornout leaf spring could transmit vibration throughout entire car
noises and all especially when there is no weight on it...
what did you use for a tranny mount/ crossember?
last question whats the angle of the driveshaft?

 

[Andy CobraII]

Thanks for the suggestions gentlemen.
I put the tranny in a year ago and just now have
been able to get back to the car. It's a '76 and 30
years is fast approaching.

I used the original c4 crossmember double hump for
the trans. The steel on that thing was thick, compared
to a fox body. I cut off one bolt-hole side and spaced it
back, similar to an article on mustang.net. As far as the
driveshaft goes, don't know the angle? just assumed the
t-5 would sit behind engine at same angle as the Rad would.
I guess since you shorten the original driveshaft by about an
inch, you will increase the angle some.

My concern is what Dano mentioned about pilot not sitting
correctly. I thought the input shaft length was correct but
diameter was different. I need to check on that. I will also
take down road. I was rushed at time of install, moving the
family.

I want this done right now that I have my garage back. I have
been thinking about getting a V8 t5 or the RAD setup. I plan on
painting over winter, so getting engine bay done at same time would
be nice.

I'll post pics soon. I know I always like seeing a II that survived

andy