Whining AW4

I have an 89 Cherokee. I took it to Rausch Creek last weekend. It did great but either the trans or transfer case (np231) started whining half way through the day. It seemed to match the trans speed rather than the transfer case but did not get enough speed to tell for sure. I also started to get the smell of burning trans fluid. When I got it home (trailered it out and back) I checked the fluids, Both units were full and neither smelled burned. Everything performed well but I am a little nervous about the noise and the smell. It is an off road only vehicle but I dont want to be a mile back in the woods and have a major problem. Any sugestions besides Drive it untill something breaks?

still asking?

Sorry I dont have a solution for you except maybe a suggestion or two. First, did you have the opportunity to take it out of four wheel drive and run it a bit to see if the noise was in two or four wheel drive, or both? Would it be possible to run it on the street for a while in two and four wheel drive for a while to see if you can get it to start making the noise again? If you are very concerned, and can do without it for a day or two, drop the transmission pan and see if there is any material, from the gaskets or bands, that would indicate a failure, or soon to be a failure. You can also drain the fluid from the transfer case and see what it looks like in there. While you are under there, look at the rest of the driveline just to be sure nothing else could be going on, too, related or not. At this point, just do some investigative work and see if you get any leads.

I had that same noise this past summer, thinking it was the trans, and thus tore it apart to find out nothing was wrong. For me it was the transfer case making the noise. The input shaft bearing was rough, and also the nut for the yoke on the sye came loose wearing the bearing out in the output shaft bearing housing. Also came to find out, I pressed the needle bearing too far in the input shaft during the rebuild, which could have been why I had some of these problems. I would definitely first inspect the transfer case for bearing wear before tearing a tranny open. The whining noise I was hearing was getting worse by the day especially when everything got hot. Hope this helps.