Transfer Case Strange Whirring Noise/Gear Whine (1 Viewer)

[nukegoat]

I just pulled off the rear drive shaft, and I finally found something.

The rear TC output flange has a good amount of play in it; I can move it in and out maybe about +/- 2mm. So I am pretty sure that's the culprit. Not sure why I missed this before, probably my fault. I am a bit embarrassed that I didn't catch this earlier...

So I could do a couple things to get this fixed:
1. Order a new bearing, pull off the rear of the case, replace the bearing.
2. Find a used transfer case, swap in the rear housing (then I get a good used bearing and get the VC back)
EDIT: There's a couple 200k TCs on eBay for ~$350 shipped
3. Order a new bearing, find a good used VC, R&R

Let me know what you guys think. Thank you everyone for the help on this, I think we finally got it!

Some axial play is normal. The output shaft is a splined input and held captive in the rear cone with a snap ring. The radial ball bearing is also held captive with a snap ring. So it's a lil sloppy.

 

[DiscoCam]

Some axial play is normal. The output shaft is a splined input and held captive in the rear cone with a snap ring. The radial ball bearing is also held captive with a snap ring. So it's a lil sloppy.

Hmm, then I may have found nothing. There might have been some axial play too, but I don't recall, I have to check in the morning.
Just seemed wrong to me because the front output is super solid and the rear output is not.

 

[nukegoat]

Hmm, then I may have found nothing. There might have been some axial play too, but I don't recall, I have to check in the morning.
Just seemed wrong to me because the front output is super solid and the rear output is not.

What kind of play did you have? I thought you described axial play

 

[DiscoCam]

What kind of play did you have? I thought you described axial play

My bad meant to say radial play.

I just checked again and it's definitely only axial play, which as you said is normal, and I just confirmed that with the FSM. So I found nothing.

I'm gonna drive it in FWD and RWD today to see if I can isolate the noise; I did this before and couldn't do it but the truck is a lot smoother than it was a month ago so I might be able to find something. I have also found a used VC so I will put that in eventually. Doubt that not having a VC would be related to this sound in any way but I found one so why not install it.

I'm going to pull apart the slip joints and manually grease them as well to make sure there isn't too much grease in there and to make sure that they are lubricated. If that makes a difference then maybe one of the slip joints are just too worn out. In my mind, this would make sense because of the locked up VC; maybe one of the drive shaft slip joints took too big of a hit.

 

[DiscoCam]

So here were the "results" of my tests:

FWD:
-no play in rear pinion
-axial play in TC rear output (which I now know is normal)
-a lot less noise when driving. Maybe 70% less than usual

RWD:
-no play in front pinion, but it felt different than the rear pinion. Rear pinion was smooth, front felt almost notchy. Did not want to float in between the backlash, liked to go to either end of it. I rotated the pinion by hand to see if I felt any R&P damage but I did not notice anything. I don't know if how the front pinion feels is within spec or not. If that might be indicative of a bad bearing, then that would be great because I think you can change the front pinion bearing without removing the diff (I think, not sure).
-axial play in TC front output, but less play than rear output
-less noise when driving. Maybe 50% less

Does anyone else think that maybe the front pinion might need a new bearing? I am not convinced, but it's really the only thing I found and I am nitpicking.

 

[SpenserAK]

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[bentambling]

My 1996 has been making a strange whirring noise at speeds above 20mph. Gets more noticeable at 45mph, then I don't really hear it after 55mph.

I've asked my passengers if they notice something but nobody else really notices it.
Sounds sort of like gear whine. It's there when I'm on the gas or off the gas, but not when the drivetrain is "floating".

I tried to get a sound clip with my iPhone but it doesn't seem to pick it up.

Some background on my truck:
-VC has been deleted. It was locked up when I bought the truck.
-U-joints have been replaced. They had a tiny amount of play
-wheel bearings have been repacked. Front spindle bushings were replaced by me as PO replaced one of them and the shop that did it screwed it up.
-birfields have also been repacked with synthetic moly grease
-U-joints are greased with wheel bearing grease, slip joints with synthetic moly
-factory locked

I changed the transfer case fluid when I removed the Viscous Coupling, then I did it again about 200 miles after just to make sure that any contaminants that might have been introduced into the case when I opened it up were now flushed out.

F&R diff fluids are also fresh and synthetic.

Otherwise it drives absolutely perfectly. No vibrations, shimmys, shakes, or loud sounds. Just normal road and wind noise on the highway.
Another strange symptom is that I feel like the sound gets worse with the CDL locked. This is both on dirt roads and straight, level, tar roads.

Any advice is welcomed.
Thank you and stay safe everyone.

Hello, were u able to fix this? I have the same issue. But i hear the sound when i take my foot off the gas pedal