High speed shudder. Tire balance or driveshaft??

[s14junky]

While feathering the throttle around 80 mph Im getting a pretty good shake. If I accelerate through it smooths out , also after I decelerate back below 75mph. Ive had bad dshaft bearings before on american cars and this is what it feels like. Tire balance?? Ideas??

[AZhitman]

Manual or automatic?

Doesn't sound like tire / suspension, it's definitely drivetrain-related if it's throttle-dependent.

[rotorimp]

You need to immediately look at your drive shaft u joints and carrier bearing.

[s14junky]

Its automatic.

Yes...I was thinking carrier and U joint bearings myself. Do they make a replacement Ujoint bearing with a grease fitting?

thanks for responses

[NJMarc]

Its automatic.

Yes...I was thinking carrier and U joint bearings myself. Do they make a replacement Ujoint bearing with a grease fitting?

thanks for responses

Bump

I can't seem to find replacement U-Joints either. I'd love a new one piece alu driveshaft but after all the motor work its not at the top of my list. (unless it is causing my ~74mph shutter).

Thanks

[jmaxima]

What style, age and mileage for the tires?

Appartently something most of us who only use good tires are unfamiliar - tires can go, out of round. Causing the same symptoms. My snow tires do this now. I had the problem end of snow season last year. When I put the 3 season wheel / tire package back on the problem disapeared. I thought they were just out of balance so had them balanced before putting them back on. But, it didn't help much.

But, it could be the U-joint or CV. Since it appeared this time when I put the questonable hard rubber back on I am taking the chance and waiting till I put the good wheels and tires on to take further action. If I get a chance I jack it up and do a cursory CV / U-joint check.

If anyone knows a good source for OEM or aftermarket drivetrain components, please tell.

The Hub seal parts are listed on the Courtesy site, but only the lube is priced.

[s14junky]

Im putting some new tires on the rear tonite. Ill post my results...thanks

[s14junky]

jmaxima,

CORECTOMUNDO my friend. It was tires...not the driveline. They had maybe 20/30% left in em. One had been repaired a few times and maybe had some fixaflat in it too...who knows. Problem resolved. Now im not freaked out at 100+ anymore.