Engine/Transmission (1998.5 - 2002) rear differential going bad?

[rborn]

I'm driving a 98. 5 3500 2wd 24 v Cummins with 179K on it. When the rear end got to clunking about three years ago I put new synthetic lube in and after a bit it pretty much cleared totally up. The rear gears are starting to make clunking noises again and I'm starting to feel a little concerned. It gets real bad awhen I pull off after pulling the trailer on straight road for a while. It also clunks episodically just when I'm starting up from a stop around town. Today, my mechanic wrote me a note after he finished servicing the truck and checking the rear end fluid level. He said the fluid level was fine, but also noted that it seemed that the rear end had a lot of "slack in it". I havn't had a chance to speak with him yet. Do these symptoms sound like there may be a differential change in my future? Does anyone have suggestions?

 

[Ragain]

I would chock the wheels, take AT out of park & check for "play" at the pinion yolk and all u-joints by twisting and up/down motions. If there is much play at the pinion, I would then pull diff. case cover and look at the ring gear for a wear pattern. Do you have the Trac-Lock rearend? (limited slip)

 

[jeeping_0]

Did you add friction modifier,if you have a limited slip?

 

[R.ebel]

Rear Diff.

My Experience

 

[MShea]

Dana 80

I just rebuilt my Dana 80. Thought only the locker was bad, but when checking the unit, found lots of metal in the oil caused by the bearing races sloughing chunks. Oil had been changed and Friction modifier was used at oil changes. Mileage on the differential... ... ... ..... 135,000 miles with some light towing. So now I have replaced or rebuilt everything in the drive train except the Cummins.

Truck is a 1999 3500 Quad cab.

Mike