[Razgriz]

Hi all,
Long time lurker here. I have tried using the search feature. Need help!

So I got a 1996 VR4 with about 145k miles. Ever since I bought it, it has had an awful vibration from the rear of the car only when accelerating from about 15-45mph then its smooth all the way to highway speeds (70+). It does not seem to be engine speed related..vibrates no matter the gear. What all do you guys suggest me to check?

Things I have done:
New PST 2pc driveshaft (with carrier bearing)
Alignment
New tires
Balance tires multiple times
Verify wheels arent bent
Done 120k maintenance
Changed fluids
New front tie rod inner and outer
New front right axle

Previous owner replaced these (from reciepts they gave me):
Front drivers axle
"Complete rear drive line assembly"

Thanks in advance

 

[Paul H.]

Did it vibrate before you put in the 2 piece driveline?

Could also be wheel bearings or the rear axles.

 

[Razgriz]

Yes. It has vibrated since before i bought it. Previous owner replaced some parts then wanted to sell it.

I checked wheel bearings with the wheels on the car. No movement. Would you bother replacing them if there isnt any movement?

Rear axle boots arent ripped but I could check them out more since they arent super pricey.

 

[Paul H.]

No probably not as long as you checked good. Jack it up and push/pull top to bottom side to side etc. Also you can turn them without any noise or feel any resistance besides the brakes. If nothing no I wouldn't.

I know in the past there were some who had vibration from the 1 or 2 piece driveline being out of balance.

Something else to try is rotate the tires and see if there is any change or if you have a good shop nearby just have the balance checked. Sometimes it may not be out of balance per say but actually a bad tire. Do you know anyone you can swap wheels with to try?

 

[Razgriz]

Yep. Been chasing this vibration forever and bought a nice set of oem chrome wheels that are known good with tires and they did not change the vibration. The PST driveshaft and all the other maintenance i performed didnt change the vibration either.

We did check both bearings well in the rear. Im confident they are fine. I will double check axles to see if they have torn boots again... I was thinking it could be a bad motor mount but i revved it in neutral and engine did not really move.

Would bad rear end bushings cause this? Im not too familiar with vehicles that are awd or rwd.

 

[Paul H.]

Yep. Been chasing this vibration forever and bought a nice set of oem chrome wheels that are known good with tires and they did not change the vibration. The PST driveshaft and all the other maintenance i performed didnt change the vibration either.

We did check both bearings well in the rear. Im confident they are fine. I will double check axles to see if they have torn boots again... I was thinking it could be a bad motor mount but i revved it in neutral and engine did not really move.

Would bad rear end bushings cause this? Im not too familiar with vehicles that are awd or rwd.

I dont think bad rear bushing would cause a vibration, just a clunk when you hit a bump.

If you got a go pro set it up under the car so it records when you are driving and see if you can see or hear anything.

 

[Razgriz]

That was my plan or to set it on jackstands and carefully get it to speed. I will update when i get around to that. Im working 10 days straight so it will be next week.

Let me know if any other ideas are made. Drives me crazy not being able to figure out something.

 

[Chang oil]

Need to give the rear suspension a good shake down pushing / pulling in multiple directions
Checking all the trailering arm bushing / all the bushing in general make sure none of then are sagging play dry rot etc.... as well

The 2 piece driveshaft or single driveshaft
Should give a slight to moderate vibration but only at high rates of speed but some worse then others (65 to 75mph)

 

[Razgriz]

Thanks for the tips. Between the oem driveshaft that was on there before and the 2 piece driveshaft, I didnt notice a change. Then again im used to the rear of the car shaking wildly.

I will get her in the air and check the bushings and everything back there again. If all else fails, ill get her to speed to see if i notice anything moving in any odd ways

 

[Chang oil]

Might only be under torque load
Weight of the car least that will start narrowing it down for you
If all else comes up good

 

[Razgriz]

Good point. Ill report back with what i find. Im hoping that ill at least know what is needed by the end of next week when im off work.

Other than the vibration she purrs and drives quite well. Pretty much rust free too

 

[paul93VR4]

Just my humble opinion but seems any old car with 1XX + miles has bad motor mounts. Easily could allow angles to change under load. Who knows maybe the angle never was good for a long time?

+1 to what Chang mentioned about bushings. Also easy to take off differential cover and check gear tooth pattern,Medical particles. lightly with prybar on ring to see if it wiggles from loose bearings. same with pinion.

+1 Paul H mentioned go pro. There is a video of someone doing that with a Evo and you can really see the torque reaction. Just better get a good magnet !

Rear axles with tapered rollers. Old grease dried up? maybe water ingression and pitted roller? Saw you mentioned you thought they were good but did you unbolt the axle off to rotate it without the wheel on? should be butter smooth.....

Just rambling thoughts. Me and my Old Grand Dad are hanging out tonight.....LOL

P

 

[Razgriz]

Hey, I appreciate any and all thoughts! I was thinking motor mounts as well but when my nonturbo had bad ones it torqued somewhat. This vr4 did not at all which is throwing me off.

Ill add that all to my list of checking the rear end. I changed fluids a few times and it all was clean and free from debris.

I will unbolt the axles and check them out..thanks for the idea.

It is so weird that if i gear down and hit the gas above 45mph, it doesnt shake at all. But from 20 to 45mph ish, it shakes the whole car and gives me a back massage lol.

 

[Chang oil]

Hey, I appreciate any and all thoughts! I was thinking motor mounts as well but when my nonturbo had bad ones it torqued somewhat. This vr4 did not at all which is throwing me off.

Ill add that all to my list of checking the rear end. I changed fluids a few times and it all was clean and free from debris.

I will unbolt the axles and check them out..thanks for the idea.

It is so weird that if i gear down and hit the gas above 45mph, it doesnt shake at all. But from 20 to 45mph ish, it shakes the whole car and gives me a back massage lol.

While (vibration) does the rpms bounce around by chance ?
In 100 to 200 increments or more

 

[Razgriz]

While vibrating, the rpms do not bounce around. Rpms steadily increases

 

[MeAgain]

Make sure the carrier bearing has the correct spacer set in them. The rear carrier gets taller spacers in them than the fronts. If the spacers are switched, the car will vibrate.

Also check rear differential bushings. When they go bad, the differential can be twisted towards one side and could cause a strain on u joints and cv axles.

 

[Razgriz]

Note made on the bushings.

Weird thing about my car. When i changed the oem shaft to the 2pc..the front carrier bearing only has the plastic like spacers that are on the top and bottom of the bracket. I looked at the fsm and saw that there is an additional spacer on top between the car and bracket.

I will see if i can source the proper spacer and try that as well.