2001 CTD 2500 QuadCab with anti-spin differential.
Last year added a Mag-Hytec diff cover for extra fluid capacity since we do lots of fifth-wheel towing. Lately when unloaded going around corners the rear end seems to chatter some and the inside wheel will spin a little. Especially noticible in a right turn where the radius is tighter. The chatter can be felt in the cab. When I installed the diff cover I added the correct amount of anti-spin diff fluid. Any suggestions what it could be? It's still in warrenty but haven't contacted the local dealer for repair.

 

Go find a big empty parking lot and do about 18 or 20 very tight figure eight turns and see if it loosens up and quits. You may not have worked the anti-spin fluid into the clutches enough when you changed the fluid.

 

I'll 2nd that.

 

Thanks for the suggestion. However, as I wrote, this was over a year ago that I added the fluid and changed the cover. Can the additive wear out? Is adding more now an option? Or should I drain completely and start with fresh lube and additive? I've heard of making tight figure 8's and adding a little additive till the chattering stops.

 

As the clutches wear, you might need to add a little more "Juice" to quiet them back down.
I'd add about 1/2 a package and "Do the 8s"

 

Thanks again for the advice. I'll be trying out your suggestions this weekend.

 

johnny that good advice if that don't work go get the dealer to put in anew one and then try a snythetic grease it works good in most units without the addative and you will have lower temps. i have had it in for about 8k now ;D