I've been fighting an engine speed vibration for over a year now. I'm hoping someone can tell me something that I've overlooked. Sorry for the length. I've been reading on here and fighting this for some time....

First of all, before I pulled my original t-5 transmission, I never noticed any sort of engine speed vibration. My original t-5 jumped out of second and whined in all the gears (except 4th of course), so I just found another to to replace it. I put in the replacement T-5 and I end up with an engine speed vibration between 3500-4000 RPM that goes away above 4000 RPM. The pilot bushing and clutch were also replaced at the swap.

I took it back apart to look at things, remove the clutch and start the engine. No vibration problem. So I contact centerforce, ask to make sure I'm putting the pressure plate on ok, and it appears that I am. Put it all back together and I have the same vibration.

I never liked the T-5 much anyway, so I bought a T-56 and everything. Put it all in and now I have a lighter vibration at about 4000+ and this one doesn't go away at any point. I could probably live with it, but it can't be good on the bearings. BTW, I've changed the pilot bushing/bearing every time I've pulled the transmission.

Has anyone had these sorts or problems with transmission swaps? Can it be anything other than alignment? Is there a way to check the T-56 bellhousing for alignment?

I'm about out of patience with this thing. Thanks in advance for any help anyone has to offer.