I'm having an issue where theres some pretty bad vibrations around 3500 rpm in 1st - 3rd. It feels sort of like driveshaft lashout, but the transmission and shifter vibrate badly too. It calms down once i get around 5k rpms or shift and the rpms drop below 3500.

Ive already had the diff bushing replaced and replaced the center bearing. Last night i pulled out the tranny x-member and checked the tranny mount and it felt pretty solid, but idk if it still could be bad. When i had the driveshaft out for the carrier bearing i inspected all of the u-joints and they looked fine. No grease leakage or rust or anything. Theres also an intermittent clunking when im starting from a standstill which is why i thought the tranny mount was bad, but theres def not enough vertical play in it to cause the clunking.

Im at a loss for what the issue could be, but i dont want to start dropping hundreds chasing the issue either by replacing parts and hoping it fixes the problem.

Thanks

 

Ended up talking to Z1 about a tranny mount but they mentioned something about clocking the driveshaft where the center bearing was unbolted. Im thinking now maybe i hosed up something in driveshaft relations. So im going to attempt a one bolt shift (90 deg) clocking at the bolt joint between the front and rear shaft halves and see if that clears things up.

The more i think about this the more it makes sense since the driveshaft was probably balanced as a whole unit.

 

Usually marks are made when DS/axles are removed. This way you can reinstall things in the exact same orientation. Was this done when you pulled things apart last time?

 

No I did not mark things. I guess since each shaft was it's own it never occurred to me to make sure they were aligned the same way going back in. I dont think it matters the orientation to the trans or rear diff as long as the orientation from front to rear shafts is correct. It shouldnt take more than 3 tries to see if this is the issue, i just hope i didn't ruin the new carrier bushing at this point. It's a PT car so it's only been maybe a couple hundred miles since i replaced it.

 

Look at the video below. Not sure what a PT car is. Front shafts? This is a awd model? Details!

 

This is a RWD 6MT 2008.

I just meant part time by PT, its parked during the winter and only driven a few days a week during the summer tops.

Clocking the driveshaft fixed the 3500k rpm vibrations. It no longer wants to rip apart when accelerating. There still is an occasional lash out vibration though when decelerating and slowing down. I'll let off the gas and start breaking and right about 3100 rpm it vibrates for a brief second, maybe this is a bad u-joint? The transmission movement is also still there when i either get on or get off the gas the shifter is moving up or down. This could only be the tranny mount, but it felt so solid that im not sure i care about that problem.

 

This is out of my realm of expertise. I just know that when removing driveline components, it's always important to reinstall in the same position otherwise results such as yours happen.

If this is happening in any gear then I don't think it's a ujoint issue. Driveshaft is spinning at different speeds in different gears. The common factor is engine rpm. I'd probably focus one of the mounts then.