I unloaded the car and took it for a spin, vibrates pretty bad. The faster you go the worse it gets. I had noticed a slight coast vibration from high speed(120+) But now is bad no matter what.

The car did wheelhop 5 passes until I figured the suspension out to make it quit. But did not notice it at the track.

The car has a 9 inch

31 spline axles

Detroit locker

Steel 1200 hp driveshaft

Nodular center section

I have it all apart now and see absolutley nothing wrong. The driveshaft slides in and out of the back of the tranny freely....output shaft looks fine and is centered in the tailhousing.

Front yoke has straight splines.

Axles look normal

Chunk looks normal, backlash is normal, gear looks great..I have not disassembled it and I see no need to.


I put it on jackstands and ran it to 90 mph and you could feel the vibration, not as bad as on the road though.

Removed rear tires and did it again, same no change. You can feel it in the whole car slightly prominent to the rear...


ANY ideas?


David

 

hmm that sounds kinda weird.. does the driveshaft still have the counter weight on there?

 

Yes it is, with a vibration that bad you would think I would be able to see it with everything apart.


David

 

u-joint?

chunk?

 

See if you can swap a drive shaft with a buddy and if the vibration goes away.

Hard to guess, but wheel hop and tire shake will F-up your car with a quickness.

 

My bet is the Driveshaft as well..

 

Brady, that is what I thought as well, but the pinion support is intact.

U joints also look and feel good.

The fluid out of the rear has that cloudy metal dust looking stuff in it. But can find no reason for it. I will pull the chunk all the way down tomorrow. I installed a new nodular housing when the car was down and used the same gear and bearings.


WIll update if I find something.


David

 

Thats my sentiment as well. Trans mount maybe?

 

I had one break there as well

 

UPDATE


I got the driveshaft back form the shop, they said it was .015 out and the rear u joint was in question, looked fine to me, so I told them to replace it with a better one.

I dont think that's it...but we gonna see


David

 

Double-check to make sure the torque arm mount hasn't broken and thrown off your pinion angle????

 

Tranny mount broke? If its the stock bushing I know they break pretty quick since they are rubber. -Mark

 

I checked it, its ok

David

 

Make sure the flexplate/bolts are good, just to be safe.

 

[QUOTE=JL ws-6;8374795]Make sure the flexplate/bolts are good, just to be safe.[/QUOTE

It wont do it sitting still in neutral, car has to be moving.


David

 

What kind of trans? I had a couple Th350 bellhousings crack on me, until I switched to an JW "Ultra" bellhousing. First time, didn't know what it was, drove home 20 miles from the track at 30 MPH, vibrating all the way. it was holding by a 2" section. Yikes. I guess that could happen with any trans, but the TH350s were vulnerable.
Scotty

 

4L60E, I will look when I get home.BUT it SHOULD do it sitting still if that was the case.


David

 

do you know for sure the torque arm isn't bent?

 

Brady it LOOKS ok, as does the mount. I checked pinion angle before I took the rear out and it was dead on where I set it.

Clyde is gonna do me a HUGE favor and check the axles to see if they are bent.

Will update when I know.


David

 

wow, mine did the exact same thing last week. horrible wheel hop and now its got a vibration and it clunks bad around turns. dont no what caused mine either. ive got a moser 12 bolt and a spool, driving on mt et street radials. it sounds like $hit is broke in the rear suspension and right under me.i would like to know as well.