Just developed a rather loud clunk that seems to come from transfer case when shifting between drive/reverse/park. I've check the u joints and all seem tight. There is free play of the output shaft yoke on the shaft and can hear the clunk. How much free play is normal. Rear differential ok. Had recent regular maintenance with transfer case fluid change (used Valvoline synthetic ATF), R/R output shaft seal and pinion seal due to leaks. No leakage now, transfer case never empty. I did not grease the splines or yoke on reassembly. Any help appreciated. Am I due for a rebuild of the TC?

Paul

 

Free play should be minimal, and will get excessive if the chain gets stretched. You will hear a clunk when the chain slack is taken up by twisting the output shaft, and if let run that way the planetaries will require rebuilding.

The OEM transfer case is good for about 80K if it is used under load much, so it sounds like you are about due as I suspect you use it in four wheel when plowing snow. It is not at all a tough job to rebuild one, and the parts are pretty reasonable, so you may want to pick up a manual from a supply house and take a look if you are reasonably good with tools.

One other thing to check is the O/D planetaries in the transmission itself. They get loose and the clunk from them will telegraph through the transfer case. The way to rule out the transmission is to lock the transmission in Park, put the transfer case in low range, and shut everything down. disconnect the driveshafts and twist the rear output shaft. Rock it and listen for chain slap with the drain plug on the transfer case open and the oil drained.

If the noise is not readily identifiable through the open plugs, then have the transmission checked.