I have a 1997 Grand Cherokee. I just finished swapping out the front driveshaft with a Tom Woods custom driveshaft and replaced the the rapazza joint with a u-joint from Rusty's Offroad. When I got the jeep, the front driveshaft had been removed. When I re-installed it with the original rapazza things seemed OK but the boot covering the rapazza was trashed so I decided to do the u-joint replacement. While swapping it out, I also changed the oil in the front diff. When doing so, I noticed there was surface rust on some of the gears in the diff which I thought was strange as there was plenty of oil. I filled the diff with new oil but now I get a very loud howl. It starts out at a fairly low frequency and the pitch increases to a howl as I accelerate. When I take me foot off the gas, the howl stops but starts up when I accelerate again. I know I have oil in the diff. The rust and the fact that the driveshaft is now are my concerns. I know there are a few postings about a howl but none seem to match what is happening.

So, any thoughts on what it might be? Also, should I be concerns about safety?

Any suggestions would be appreciated. Thanks in advance.

 

I would guess that it's related to the front differential. Can you put it on a lift to get closer to the noise?

 

The question should be what type of transfer case you got?

 

you need the diff rebuilt
previous owner didn't want to and removed the driveshaft instead

 

I don't think that's right? Because even if the driveshaft was off, the diff is still moving when the vehicle is moving. So regardless of it being connected, it would be making noises with or without a front drive shaft. Sounds more like a transfer case issue

 

R&P and/or bearings are trashed, won't usually make a fuss when not under a load it's JY axle time.

 

according to your profile, you have the V8 engine, which means you have the 249 transfer case. with the front driveshaft out, the front diff is not recieving power. when you put it back in, the diff is now getting power (249 is an all-time 4x4 transfer case) and the issues arise. bad bearings are my bet

 

I see you are in High Point....Im in Stokesdale. Ive got two 98 ZJs at the house if you need anything. Let me know.

 

Are you sure the noise is coming from the front axle? IF it's a 249, and IF the front shaft has been removed for a while, it could be the transfer case. The 249 doesn't like driving only one axle.

 

if its a V8, its a 249. and since he has a 97, the 249 doesnt care if its only driving one axle. the early ones (93-95) would destroy the viscous coupler if you drove without the front driveshaft in (they would also roll in park), but the 249 was redesigned for the 96+ ones and eliminated both of these problems

 

Well to settle if its transfer case or axle, OP is going to have to open up one or the other or both. I still think its the transfer case, there is load put on the bearings regardless of a driveshaft is on or not. It would be making noises without the drive shaft.

 

I guess I should shut my mouth about the 249. I've got the 242 and like it.