I have a 1999 1500 Sport 4x4, 5.9 Gas Automatic. I THINK it has a Dana 60 or Chrysler 9.25. It has a tag on it that says 3.5, which I assume means it has 3.55 gearing, and it should be an LSD unit.

My problem is that it vibrates above 60, and it’s pretty heavy. It vibrates with the rear end lifted in the air, even with the wheels off. It does NOT vibrate with the transmission or transfer case in neutral. I’m guessing the problem lays between the rear driveshaft and the rear axle.

I took the diff cover off to have a look, and I found several distinct pieces broken off at the bottom. The oil itself looked good, and the teeth on the gears didn’t look chewed up and I didn’t notice any pieces missing.

I’ll attach pictures of the pieces I found, if anyone knows what they are I need to know!

thanks babes

 

Yayyy. Time for a rebuild.

 

Clutch retainer clips. Or, at least, what's left of 'em.

Probably not the cause of your vibration though. How are the U-joints?

 

They should all be new. I say “should” because a shop charged me to replace them all, back when I was naive I do take the truck off road pretty regularly, but they ujoints haven’t seen water in a good while. I grease them now each time I get done.

Is there something I can do to check my ujoints, or do I just need to replace them and hope for the best?

 

Jack up the rear of the truck and support the rear with jack stands. Get up under the truck and try to move the driveshaft up and down, forward and back. If there is any movement, try to isolate where the movement is. Also, look closely at the driveshaft to see if any welded-on weight has come off, as this could throw your driveshaft out of balance. I've seen weights added typically just behind the front or rear of the driveshaft. Lastly, try to move the rear of the driveshaft where it connects to the rear up and down/side to side to see if there is any play in the rear end pinion bearings.

 

I took the rear drive shaft out and drove it at 70 mph, and it still shook like it does. I also replaced the rear ujoint at the axle and the shaking went away just a little bit, but it’s still there and it’s still noticeable.

I’ve also lifted the rear end off the ground and spun it up to 70mph, and it still shook so I know it’s not an issue coming from the front end.

So it looks like I’m facing a rebuild or replacement. That’s okay though, I wanted heavier axles anyhow.

 

Replacement is actually cheaper than a rebuild......