Tractor Repair: Caseih 5250 front differential, friction modifier, pint bottle

Question
The front diferential on my CaseIH 5250 will chatter and jerk when turning.  It does not make any noise when driving straight, and does not do it on every turn.  It is more prone to do it when there is more weight on the front end, the front drive shaft is on, and when the MFWD is engaged.  It will do it rarely even with the front drive shaft off.  We have changed the oil, checked the u-joints, and for any wear in the king pins.  Short of tearing the differential apart we do not have any other ideas.

Answer
Hello,

  If this is a limited slip front differential, there is a friction modifier additive for the oil that must be used to prevent the exact problem you are having.  The Case Ih part number is B91246 and it comes in a 1 pint bottle.  See if the operator's manual recommends it for this machine when changing the front axle oil.  If there was an internal failure, you would have noticed metal particles in the old oil when it was drained.  If you haven't already done so, you should also drain the oil out of the outside planetary hubs and see if there are metal particles in it.  These oils should be changed every 1000 to 1200 hours.  If you do put in the oil additive, the effects won't be immediate.  It may need to be driven for a few hours to circulate with the oil before you see a difference.

               Hope this helps,

                       Arnie