I have on 03 1500 suburban 4x4. About 190k miles. Transmission was replaced at 160k. Everytime we shift from park and accelerate from a stop there is a lag time before the vehicle engages and slight thud coming from the rear. When i get under the car i can twist the Drive train by hand. It seems their is significant play before it will engage. Is this a Ujoint issue?

Thanks

 

Welcome to the forum.

You should be able to detect any looseness in the U joints when you're under by twisting the drive shaft slightly back and forth. If it's not the U-joints then I would suspect the sloppiness is in the rear end itself.