[stangmata]

When driving this awful whine/high pitched groan started coming from under the Jeep. It only happens under power and is worse when applying just a little throttle. It gets louder with speed. In neutral or coasting it doesn't make any noise.

The noise to goes away by shifting into 4wd and then back into 2wd. Then the noise happens again about a 1/2 mile or so later and I have to go through the same t-case shifting dance. This evening, it felt as if it had shifted into 4wd on its own.

The shifter isn't binding and seems to be functioning properly. The 4wd light doesn't illuminate unless I physically shift the t-case.

My plan is to do a visual inspection, drain the fluid, and then pull the case and see what I can find. Any other thoughts or ideas?

 

[rlenglish]

You are on the right track.
I assume your linkage is adjusted properly, make sure your transmission and engine mounts are okay. A shift in the engine could cause the linkage to move,
check for play or looseness in your front transfer case yoke. It can cause unusual problems.

 

[stangmata]

check for play or looseness in your front transfer case yoke. It can cause unusual problems.

Perfect! I’ve been chasing driveline vibes and have been meaning to pull the front DS. I’ll see if that makes any difference while I’m at it. Thanks!

 

[stangmata]

Pulled the front shaft. Checked the cable shifter. No visual issues. The noise is still there. No noise noted in 4-LO. Once I went back into 2wd the noise came back after 1/4 mile.

ill disconnect the shift cable and see if that helps. I’m really baffled.

 

[stangmata]

Plenty of fluid, no materials in the fluid and looks fresh.
Pulled the rear driveshaft. In 4wd the play between the front and rear yokes seems normal. No noise, no strange feeling. Everything seems very normal.

 

[rlenglish]

Sounds like a disassembly. Could be something as simple as the shift fork pads worn out letting the gear slightly engage, or something way deeper.

 

[stangmata]

Yup. Apparently the front bearing can really cause a whine. I’m calling a shop Monday to get an estimate - not sure I have the time for a garage rebuild.

 

[RubiconRic]

Did you figure this out? I had a noise from '04 and it turned out to be the ring gear bolts working their way out of the rear differential and scraping on the inside of the axle housing.

 

[stangmata]

I’m dropping the tcase off tomorrow for a rebuild but I think I’ll pull the rear cover first.

 

[stangmata]

I love how your brain can play tricks on you..

The transfer case was 100% fine. That was a $500 dummy tax.

The noise was coming from the rear differential but presenting itself in an area where I thought it was the t-case. Clicking the t-case into 4wd was likely removing the stress from the rear diff, temporarily eliminating the noise. As for going into 4wd, that was my imagination.

The shop that re-geared my jeep was kind enough to put a new R&P in free of charge. They claim that I improperly broke in the gears and caused excess heat. I followed the break-in instructions very closely, but alas, the shop showed me the ring gear and from what they describe, the ring gear ended up with rough spots on a drive side and a weird anomaly on the coast side. There is a new issue with the rear diff though and I'll start a separate thread about that.

 

[stangmata]

The saga continues here:

Fresh regear - rear diff puking excessive fluid from...

2005 Rubicon, manual, 4:88 gear, SOLID diff covers, 106K miles. In October I had 4.88:1 gears installed in the jeep by a reputable shop. After 500 miles (over 2 months) of following the break-in procedures that I was provided, the rear end developed a low groan that turned into a whine so bad I...

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