Looking for advice. Today while driving my truck I noticed a vibration around 25-30 mph. When I let off it goes away. 1 piece driveline so no carrier barring u- joints seem tight. When I let off and accelerate I can hear a “clunk”. The only thing that seems like it may be an issue is the rubber mount under the transfer case, mounted to the cross member. Seem like there is a lot of flex to it. Any ideas? Rear end maybe? Transfer case maybe? I’m completely stumped and don’t want to throw bunch of money at it without knowing.

 

First thing I would do is pull drive shaft out and check u joints.

 

Ended

Ended up being a u joint 🤦‍♂️

 

Thanks for the update.

 

How did u check the u joints? I’ve seen some that look ok, no play but once pressed out the caps were cracked and needle bearings straight seized. Get a big pry bar and wedge in to move caps....at least a 24inch prybar. Sometimes you need a lot of leverage to Find the play