vibration problem!!!

well i am wondering on my 2004 s10 zr5 if the problem could be the u joints or cardan joints, if im starting to vibrate or shake when i hit 50 mph, and at 30 when im towing a small trailer and a mower. i just had new tires put on it and the wheel bearings on each side replaced any ideas if its not the joints

I had so much trouble with the driveline, especially those miserable Cardan joints after I modified the engine for more hp, that I had a custom driveshaft built by a local shop (back half of shaft, but both the front half and back half were balanced as a unit). This is the weak link in the Chevy drivetrain, as I see it.

Then I purchased a driveline alignment kit from JTR (Jags That Run).com and that put everything in alignment. I have no vibration on launch and the shaft is smooth as silk. It was in the truck for two years with a lot of launches on it and I sold it to a friend who drives it harder than I did and it is still good to go. You may want to do the same, especially if you haul things and don't like rebuilding that miserable drive shaft.

Later...

eti engineer

well i am wondering on my 2004 s10 zr5 if the problem could be the u joints or cardan joints, if im starting to vibrate or shake when i hit 50 mph, and at 30 when im towing a small trailer and a mower. i just had new tires put on it and the wheel bearings on each side replaced any ideas if its not the joints

Welcome to AF.
I would recheck tires and tire balance.
Shake at 50-60 mph points to tire balance.

Have you lowered or raise it?
Has the drive line ever been removed or a joint replaced?
How many miles on it?
Has the Cadan center joints ever been greased?

no i havent raised it or anything its still all factory, i have 46,750 on it, and ive had two times the right ball joints replaced and one left the checked tem about 100 miles ago when they replaced the wheel bearings on either side, they said they were fine, and to my knowlege those joints have not been greesed unless theyve done it on there regular maintanace thing

Get a needle for your grease gun and see if you can geese the center ball on the cadan joint.

I have the same vibration problem with my 2000 Blazer Zr2, only it happens at 70 mph! I just replaced the tires and the problem went away for a week and has reverted back to excessive shaking at 70 mph. At 20-30 mph there is a thump thump that sounds as if I am rolling over rough terrain. Chevy said the upper and lower ball joints need to be replaced. I am probably past due for having all zerk fittings greased.