Rebuilt Driveline and Vibration...Need help/advice

[vinnie7009]

I already read the other post regarding a 94 Cobra having a vibration problem and took what great advice you had there and am using that to potentially help me with my problem, but I wanted to exactly describe my situation to see if anyone else has any further advice or potential answers to my problem. Ok, so here it is.

Just finished replacing my entire driveline after I had previously blew out my stock t-5 tranny, clutch w/pressure plate and all, cracked the bell housing in the process, and broke the yolk bearing on the driveshaft. I had it replaced by a very good, and well known mechanic with a great reputation, so I am almost 100% certain it was all installed right. I replaced everything with a brand new tremmec tranny with a Pro 5.0 shifter, new Spec Stage 1 clutch, new yolk bearing, and new bell housing of course. Everything was brand new with all new mounting hardware/clutch hardware that is needed. Mechanic finished it yesterday and took it for a test drive and it had a vibration he said. The vibration as he explained it was slightly more pronounced at the lower RPM's, but was still consistent through the uppers as well. I know from reading the earlier post that it may be my flywheel that is warped/defective as this is the only thing I did not replace, but just had it turned instead. I understand this may be one of the causes and have told him this already. However, if my memory serves me correct, I think I remember reading a post by someone that mentioned that a new Spec clutch will produce a vibration until it is "broken in" and may even be still present even after this. I was wondering if anybody else has heard of this or knows anything about this?? If so, maybe ill see if it gets better after I drive the car very gently to break all the stuff in. Of course, any other recommendations/advice any of you may have I will be more than greatful to hear, as I just want this problem fixed and to get her back on the road as its been too long. Thanks all!

[SimplyOrangeTPS]

once the clutch is engaged , it shouldnt have a vibration.did you put the driveshaft back where it was originally on the rearend?. im guessing you broke the bellhousing and bearing by trying to suck it in using a bellhousing bolt, if this is the case, it is possible that you distorted a crank bearing, ive seen it before...il think some more and let you know what i come up with.

[vinnie7009]

Thanks for the quick response SimplyOrangeTPS. Im not really sure if the driveshaft was put back where it was originally on the rearend. I know he said he aligned everything after installing it, but Ill make sure to tell him this as well. Also just for clarification purposes, as odd as it sounds/hard as it may be to beleive, the bellhousing was actually cracked/broken along with the yolk bearing at the time when the tranny blew out. It was a pretty big blowout....going about 105 mph on the E-way when it all happened. The mechanic as well as another very knowledgable mechanic couldnt beleive or understand what actually caused it to be that bad. In fact, they opened up the old tranny and it was just all one big mess. So anyways, just wanted to clarify that these were broken before hand and not while he was trying to reinstall everything, which is what I interpreted from your response, but I may have interpreted what you said wrong (as I dont know much about this stuff). Just wanted to let you know this in case it helps you when thinking more about this. Thanks again mate! I really appreciate it.

[SimplyOrangeTPS]

yea, that rules out the vibration being an engine bearing....id check into the driveshaft, does it do it at idle? if it only does it going down the road, maybe the transmission atempted to lock up and it may have tweaked the driveshaft or ring and pinion, this is a tough one.give me some details about when it vibrates and goes away and if it does it in nuetral when you give it a little gas.

[stanger007]

I'd look at the harmonic balancer, they have a bad rep for going out around 100k-120k miles, I've replaced quite a few where the rubber begins poking out the backside of them.

With the car off you can get under the front, center of the engine and look at the balancer (behind center pulley). Also if you run the car you can look from the top and see if there is any wobble to it.

Wes

[Benjytps]

check also that the driveshaft was rebalanced after being repaired.