Differential or suspension?

[Dihrdbowti]

Hello all. First I would like to say that I am a new diesel owner and I have found this forum to be invaluable. Ok here goes I have a 96 GMC Yukon with the 6.5L TD. I seem to have not really a noise but more of a feel. Whenever I stop or start if feels as if the back end either drops suddenly (acceleration) or raises up (stopping). From a stop I can start out slowly and can keep the backend from dropping for a little bit but as I accelerate harder it will drop. I was in the tranny shop after a complete rebuild of 4L80 and T-case to make sure everything was ok after a few thousand miles and the tranny guy said it was in the diff. I just have a hard time believing that. I do not have any other noises or issues with the diffs but the suspension seems to sag a bit in the rear. Any and all comments views etc are welcomed.

Thank for any help

[C.K. Piquup]

I`ll take a stab.How are the shocks?Original?At 80,000+miles they could be getting mooshy.How does it feel in curves?Try the recoil test.Grab the bumper and raise-depress-raise-depress a few times(watch your back)and see if it continues to bounce when you stop.

[Dihrdbowti]

THanks for the response CK. Yes the shocks are original and I have plans on replacing them soon. The bounce test appears to show life in the shocks still. I don't have too much body lean and I recoil/bounce once and come to a stop. I am following another lead right now that involves the drive shaft sliding in and out of the t-case under a torq load and not having the proper amount/type grease applied. So far it is looking like this may be the culprit. I will have more info this weekend.

Thanks