serious AWD vibration issue... need help!

[Goro21]

Searched my brains out on this subject and really have nothing.. long story short..

My trans went out several months ago.. replaced it with a shep tranny. (had a local shop rebuild the t-case) Anywho, the car vibrates like crazy between 50-70mph. My local shop said it looked like the front axles were slightly bent, so I had them replace both with brand new ones. (cv joints, the works.. 600$ = gone) .. replacing them made it better, but the vibrations are still there. Does anyone have any ideas? I'm about ready to say screw it and drive the car into a wall. I dont think it could be a tire issue as ive read about... this vibration happens wether your accelerating, decelerating, or just maintaining a speed in that area.

Thanks in advance!

 

[weith1111]

U-joints most likely. Last time they were replaced?

There is a very basic guide to vibration diagnosis in any car manual (haynes/chiltons):

It basically asks if it is speed specific, rpm specific, only accel, only decel, happens in and out of gear or just in gear, etc.

edit: maybe not u-joints if it vibrates "like crazy" but it's worth checking, i'd do the diagnosis in the manual, it will pinpoint a couple things to check.

 

[ECLIPSE4x4]

This is another shot, are you sure it is not the wheels?

How long did the car sit without a tranny or not moving, could have flat spots on the tires.

 

[Ryan95tsiAWD]

does the car pull in either direction or just vibrate?
have you jacked the car up and checked your tierods/control arms?

if it is just vibration i would think tires as well.

 

[Goro21]

The vibration is not rpm specific, nor gear specific.. only speed. Its the worst right at 60mph (car feels like its going to shake apart) .. only slightly noticable at 50 and 70. The car sat for around 4 months when i was waiting for the transmission and t-case, so i guess a wheel check wouldnt be a bad idea.

Also, the steering wheel does not shake or vibrate at all when the chassis is vibrating. I can let go of the wheel at high speeds and the car will go straight as an arrow. I will also check the u-joints, i suppose anything at this point could be a problem.

Thanks for the suggestions guys, hopefully ill be able to pinpoint this issue

 

[ECLIPSE4x4]

Please say you had the drive shaft strapped up while the tranny was out and not hanging down.

 

[weith1111]

^^^ my $'s on that one

 

[Goro21]

ha, I'd love to answer that one, but i did not do all of this work myself, I had a shop do it. (trans swap is not something I have time/space to do myself)

I was thinking in the back of my head that the driveshaft might be the issue. I'm going to have it looked at this weekend .. good to have some other feedback on this

Think this is something I could swap out myself without a lift?

 

[Waredtalontsi]

Have you checked the carrier bearings on the driveshaft?

 

[Sbeing1]

i had the EXACT problem when i bought my car, i had axles replaced, cv joints replaced, alignedment, everything!! i couldt figure it out. then i bought new rims and the vibrating went away, it was EXACTLY to a T how your describing it. speed specific vibrating. id say put some other wheels on it and see if the vibrating stops then.

ps- also maybe check yur wheel bearings, to do this, press your foot on each of your tires (put one foot on top of tire and push as hard as u can) if theres any play in them, your wheel bearing should be changed. just a thought

 

[Goro21]

We'll, I got a few PMs regarding this issue, and think I may have overlooked something. The car vibrates between 50-70 ONLY when the clutch is engaged. If i get up to about 65 where the vibrating is the worst, push the clutch in, the vibration goes COMPLETELY away. (had never put much thought to this before) .. I can coast at those speeds all day long without any issues.

So, I'm not sure if this would be a good assumption, but Im not sure driveline-tires/wheels are the correct place to start looking. I just assumed that the transmission would be 100% bullet proof.. would you guys think it could still be the driveshaft? (you would think that the driveshaft would vibrate at all times wether the clutch was engaged or disengaged)

Maybe the transmission has some issue? any thoughts?

Thanks again guys, really appreciate your help with this.

 

[wishihadatalon]

My car has a weird noise/vibration at highway speeds. I am 99% sure its the carrier bearings. Mine are really easy to move side to side in the rubber. The clutch thing could be because of any engine load is no longer there when you push in the clutch.