I just did the pump rub fix in my transfer case over the weekend using the wear plate that sits in the back case. Put it all back together and drove a little bit in 4WD to verify everything was working. It drives perfectly fine in 2WD but in 4WD on decel is a noticeable whine from the front. It's a lot louder at lower (less than 30mph) speeds on decel. It could've been doing this before since I RARELY use 4WD. Its also noticeable when cruising and I put it in 4WD where the front just barely whines but I think that's normal. I also put on new rear tires a week or two ago but I doubt the slightly larger diameter in back would cause the front to whine right? I did read about issues with these front diffs and some lock tabs breaking off and allowing a lot of movement but just curious what you guys think. Truck has 130K miles and like I said very rarely is put in 4WD (just in the winter a couple times).
Thanks

 

Someone's gotta have an idea on this?

 

It's Normal. As long as it's not howling mega loud it's nothing to worry about.

 

Maybe, but I know it hasn't always been that loud. I've had the truck for roughly 80K miles now and it definitely wasn't that loud last winter or the winter before. I doubt it's anything I did w/ the transfer case - I even match marked the driveshafts to the yoke on each diff to ensure they went back on the way they came off.

 

If it were mine I'd monitor it then since you have had it long enough to tell it's not normal. If it changes anymore I'd drop the diff and split to check bearings. Might try changing oil in the front diff first.

 

That happened on my S10 Blazer once. One Day it just started howling really loud. IIRC it would do it in both 2 and 4wd. As if the front diff was trying to engage itself.

As I would slow it would get louder and louder and then just POP really loud and be quiet again. Never figured out what it was. It just went away on its own. Surely something was grinding away inside but front still engages just fine so I'm not too concerned.

 

Drain the front diff and see if there's excessive metal filings/chunks on the drain plug magnet, I got a ton on mine last time I checked it, and my front diff makes some pretty unhappy noises. I'm sure that I have a broken bearing retainer and my front diff is shifting around in the housing.