98 Sonoma...Drivetrain Vibes

[R6MGS]

Was just out looking at a 98 Sonoma v6..only 70k miles on the clock...Amazing condition for the year, completely spotless. Luckily I decided to drive it before buying it.....Discovered a bad vibration, worse under acceleration...Seams like a drivetrain problem. Anyone know what might be causing this? Any ideas? The owner says he's going to get it fixed, but I am wondering if this is a sign of more to come.

 

[tony barnhill]

Which engine did it have?

 

[R6MGS]

That would be a 4.3.....I just talked with a friend who has similar problems in his....had the driveshaft and u joints done....still vibrates....so i assume it's a tranny thing?

 

[saabmp3]

Differential and the CV joints in the driveshaft (assuming it has a CV joint) or the slip yoke would be my first guess. I would physically get under the vehicle and see if there is any play in any of these connectors.

Ben

 

[michalotti_tr]

Not really any help because my old S10 never had the vibration problem, but a SWAG would be to look at the center carrier bearing - those things are notorious for going bad(in general, not just S10s) and causing driveline vibration. In a former life I worked in an auto parts store and sold many a carrier bearing for that exact problem.

 

[tony barnhill]

My '92 Sonoma has a 4.3 in it - over 300,000 miles on the truck - no significant vibration though people have told me that's pretty standard for that engine....but, then again, I may just be accustomed to it.

 

[R6MGS]

Someone of the S10 forum suggested u-joints....So I guess it could be anything in the rear driveline....It definatly feels like it's in the rear somewhere. I've heard mostly all good about the 4.3 so I don't think it's engine related. If the dealer gets it fixed properly I'll take it....But I assume if he can sell it to some poor soul without him noticing this guy wouldn't hesitate.

 

[Bugeye58]

Ron, check the motor mounts and the rear tranny mount. Have the dealer check for propshaft imbalance and the proper relative angle between the pinion flange and the u-joints. They should have the stroboscopic tool for checking the balance, and the gauge for the angle.
Believe it or not, the way to balance the driveshaft on the vehicle is by using regular worm type hose clamps!
Any good dealer will have an Electronic Vibration Analyzer, (EVA). Trust me, EVA is a smart lady. When I was at the GM Proving Grounds, I used one to find a bad alternator bearing. I also used one to isolate overtorqued lug nuts on my mothers Buick.
Jeff

 

[R6MGS]

Cool, thanks Jeff....I inquired about another truck today and the owner mentioned he had the driveshaft replaced due to vibration. Apparently the u-joints are built into the driveshaft, which in itself is pretty complicated.

 

[Bugeye58]

Ron, I vaguely remember some problems with the '97-'99 S-10's with propshafts made in Three Rivers.
Jeff

 

[tony barnhill]

Yeah, its not something we can do in the driveway - I've had mine replaced twice in the 300,000+ miles I've put on it.

 

[R6MGS]

Yeah...apparently a driveshaft runs about $1000 CDN...That will be the first thing I check out from now on.

 

[tony barnhill]

& I think there's 3 U-joints to replace, if memory serves me.

 

[saabmp3]

[ QUOTE ]
Yeah...apparently a driveshaft runs about $1000 CDN...That will be the first thing I check out from now on.

[/ QUOTE ]

WHAAAAA?!?? 1000 bucks? The drive shaft in my Jeep can be custom made for around 300. That's a custom, rock crunching, SYE with the double u-joints on one end (3 ujoints total) drive shaft MUCH stronger than most stock shafts. I have a hard time thinking 1000 is a legitimate number, maybe from the dealer, but no indy's?

Ben

 

[R6MGS]

I got that number from a friend....So I am not sure as it's accuracy...The more people I talk to the more I learn about these.