So I get this "bum bum bum" sound coming from the car when I am in between 15-40 mph. I checked the U-joints and they are solid. I spun the wheels to check the hubs and there seems to be minimal grinding if any at all. Could it be the transfer case? I'm going to change the fluid in the transfer case to see if that helps but im looking for any advice I can get.

Thanks,
Wes

 

did you remove the driveshaft to check the ujoints?

 

I did not. I got under the driveshaft and tried to see if the ujoints were loose in any way. I tried to turn the driveshaft with my hand and tried to wiggle ujoints. Everything was solid with no movement.

 

imo, remove the driveshaft and move each joint both directions....the joints may be dry and seized.

 

I have now taken the driveshaft off and checked both U-joints. Both are doing fine and can move as they are supposed to.