Squeaking noise from transfer case (?) after elephant hill (1 Viewer)

[thegadgetguy]

About 45 minutes from home on the way back from Canyonlands NP, having done elephant hill and some other trails, I noticed something was making a lot more noise than usual. It was coming from the transmission/transfer case area and at highway speeds sounded like a rattle. It did not sound like a good noise. It was still making the noise the next day. Here are the symptoms as best I can describe them. Video included below.

• Noise is present, in some form, at all speeds
• Noise is not affected by braking or cornering
• Noise is not affected by locking CDL or by putting transfer case in Hi, Low, or Neutral. It is only dependent upon vehicle speed
• Noise does not go away when accelerating or coasting, but it does change slightly depending on which direction/how much the drivetrain is loaded
• Removing the front driveshaft makes the noise go away completely.
• There is evidence of a small leak from the front output shaft seal on the transfer case.

I had someone else drive the truck while I listened from the outside. My best guess from this test was that it was the front output shaft bearings in the transfer case. This truck was driven for awhile with non-ideal driveshaft angles, though I think they're pretty close now. I wouldn't be suprised if some of my driveline bearings fail prematurely due to this history.

I removed the front driveshaft, and the noise went away completely. I inspected the driveshaft (DC, Tatton, installed new last year) - no noticeable play or binding on the joints. I re-greased the driveshaft (<10k since last greasing). I reinstalled the driveshaft, and the noise reappeared, unchanged.

I also inspected the front transfer case output shaft. It appeared to have been leaking, which is a recent development. Just how recent I couldn't say. It had some rotational play, which I expected. It may have had some radial play, but it was hard to tell. It definitely had a small but easily percetible amount of axial play. From reading other threads on the bearing, it sounds like play should be on the magnitude of < .004 thou. I will take another look tomorrow, but I believe there was a lot more axial play than that.


Here is how my truck is setup right now, for reference:

• 35" Duratracs
• ~4" lift front, ~3" lift rear
• LandTank/Whit's End 4" caster plates in the front w/oem bushings
• Tatton DC front driveshaft - angles look pretty good
• Rear adjustable UCAs shortened to bring pinion down - as far as I can tell I'm within 1 degree of having flanges parallel
• Stock rear driveshaft with new U-joints within the last 40k (?) miles
• 5.29 gears in the diffs, so driveshafts are spinning pretty fast on the highway with 35s

This video is of coasting down from ~25 mph. I downshift to 2nd halfway through. It sounds more like a rattle at higher speeds, but is a squeak/squeal at lower speeds:



I'm going to get some gear oil tomorrow and top of the transfer case and front differential to see if that makes any difference.

Any help troubleshooting and narrowing in on the issue is greatly appreciated. This is my only car, so larger jobs like taking apart the transfer case require a little more planning to pull off than they otherwise might. Thanks in advance!

 

[Grandlooser]

Certainly sounds like a u joint at the end there. Much easier and cheaper to throw some new joints in first before tearing into TC.

 

[ppc]

Forget topping off the fluids. Do a complete drain and fill and inspect the old lube for any issues.

 

[BlueCruiser84]

19.3 mpg... you’re right, something is wrong.

What ujoints did you get with the Tatton shaft? My money is on that, not the TCase. Tcase front output still spins when the front shaft is off. If a bearing is THAT noisy you think you’d still hear something.

 

[thegadgetguy]

I still have my old front driveshaft. I’ll put that on tomorrow to test the U-joint hypotheses. Thanks for the ideas guys

 

[MoJ]

Start simple, lube the u joint.

 

[thegadgetguy]

Hey guys, thanks for the input. I put my old shaft back on and it made other noises, but not the one I've been trying to find. I went back to inspect my DC shaft again and the U-Joints are fine. It's the centering ball thing on the DC side that's squeaking. For whatever reason I wasn't able to make it squeak on the bench until now.

I think I still need to put the transfer case on the schedule though due to the leaks.

Thanks for the help!