Vibration only on acceleration

[huetherb]

So I've been trying to figure out what the heck is going on with my 03 z71. It started vibrating/shuddering heavily only on acceleration/under load. I can feel the vibration in the steering wheel. I have replaced wheel bearings, cv joints, checked u joints. Here's something I can't quite figure out. I engage cruise control, and the vibration occurs as it accelerates to maintain speed. If I engage 4 high, the vibration nearly goes away. When I switch back to 2 wd, vibration comes back. Anybody have any ideas? Any help is greatly appreciated.

 

[blueflamed03]

driveshaft?

 

[andrew383]

Could be a sign that the trans is starting to go..What does the fluid look/smell like???

A u-joint going bad will result in the same symptoms also...

 

[huetherb]

I have looked at the driveshafts, and they don't look out of balance while they're turning, but I haven't pulled them off and taken them to a shop.

What am I looking/smelling for with the tranny fluid?

Also, what's the best way to "test" a U Joint? I just tried to shake the joint/shaft end around and see if there was any play.

Thanks for the feedback!

 

[Gordy]

I have looked at the driveshafts, and they don't look out of balance while they're turning, but I haven't pulled them off and taken them to a shop.

What am I looking/smelling for with the tranny fluid?

Also, what's the best way to "test" a U Joint? I just tried to shake the joint/shaft end around and see if there was any play.

Thanks for the feedback!

Brown tint, and burnt smell. On the tranny fluid

Can you correlate vibrations with certain gears, or shift pattern.

Torque converter maybe