2510 Mule Front Differential grinding noise
 

Hello,
I am new to the forum. I have a Mule 2510 4x4 1998 model which I bought new. My local dealers (2) haven't a clue about my problem. Their solution is to throw parts at the Mule, hoping they get lucky. My problem is that when decelerating or coasting downhill in 2wd, I get a noise similar to gears grinding in the area of the front differential. I have checked the U-joints. OK. I have checked for slack in the front differential and CV joints, and found nothing out of the ordinary. No oil leaks. Changed fluid in front differential and transmission and checked for metal fines in the fluid. Found none and replaced the fluid. Checked the 2wd to 4wd shift arm and it moves freely and you can hear the shift slider moving inside the case. 2wd to 4wd shift cable needs replacing, so I physically tied the shift arm in 2wd only to eliminate the possibility that the 2wd to 4wd was partially engaging when I remove the load from the drive under braking or coasting downhill. Made no difference. All four tires are same size and properly inflated. I can shift the primary transmission into neutral when noise starts and it instantly stops. Makes noise mainly in 2wd, but on rare occasions, it will happen in 4wd. Machine has 856 hours, which is nothing for a machine its' age. I am at a loss for a solution, and the dealers are lost as well. Any suggestions would be appreciated. Thanks, Goomer