Transfer noise & vibration + Intro

[mtncruiser]

I have been lurking for a while but never got around to joining. This site was definitely a huge help when I replaced the HG last November.

I have been trying to diagnose/fix a driveline vibration issue for some time. I did some searching but couldn't find this exact problem. I can hear a "bearing" type noise at most speeds above ~5mph and this is accompanied by distinct vibration of the transfer shifter. At low speeds, say < 5mph, the transfer shifter will move front-back by about 0.5" and the frequency of movement increases linearly with vehicle speed (not related to engine speed) to a steady vibration at hwy speeds. The shifter vibration is present mainly when I am on the accelerator while the noise seems present regardless of accelerator position.

To date I have:
- Drain/refill transfer with Mobile1 gear oil
- Replaced all u-joints and balanced drive shafts
- Used CDL to drive with front or rear drive shaft removed. Vibration and noise is present when rear (or both) drive shaft is installed but not when driving in FWD only. With the rear drive shaft removed I tried to feel for slop in the transfer output but this was inconclusive.

The above diagnosis leads me to believe the cause may be in the rear output of the transfer case. Can anyone chime in with their thoughts or experiences?

Thanks!

 

[Romer]

Sounds like a similar problem that I had. Put in some 140W gear il (cheap stuff). If it is an output bearing or worse, the tone of the noise should change a bit with the thicker gear oil.

 

[CJF]

^^^^

Good advice right there...

Welcome,

Curtis

P.S. Oh, and congrat's on getting through a HG job by just lurking!

 

[mtncruiser]

Thanks guys - I'll try some heavier gear oil and report back.

CJF,
The HG didn't go completely without a hitch. When I disconnected the air flow meter (VAF style), I unscrewed the connector and ripped the guts out of the meter. The truck wouldn't start so I freaked out for a day until I remembered what had happened. Luckily I was able to re-solder the connections and save a $700 mistake.

 

[mtncruiser]

Follow up

Follow up:
2 weekends ago I refilled the transfer with some 140W Valvoline gear oil. The "bearing" type noise did change in pitch to a higher frequency but unfortunately did not go away. It is most noticeable on a cold start when I first start rolling - it's a distinct whine (louder than with the 90W oil) until the gear oil gets moving around and warms up. The transfer shift knob vibration is still present at about the same level as before.

I sent a sample of the used gear oil to Blackstone but that was inconclusive for wear metals, etc. (I'll try to attach the report at work tomorrow)

Based on the fact that the noise changed with a heavier oil, does this sound like some bearing issue in the transfer? Has anyone had to replace an output bearing or rebuild their transfer case?

Thanks again

 

[Firedog]

Since your noise changed with the gear oil change this will have nothing to do with your problem but....
When I first bought my cruiser I was positive that I had a transfer case problem, same noise as you, same movement of the shifter, same feeling in the shifter. I was absolutly positive that I needed to rebuild the transfer and I was pissed!
I am not new to transfer cases, I am an ASE master mechanic, and I have worked on countless Land Cruisers.... I was positive it was toast.
I decided to drive the truck one more time to have a good listen to the noise and I wanted the interior to be as quiet as possible. I turned off everything and closed the cover over the sunroof.....the noise all but went away! Opened the cover over the sunroof and the noise was back!
The problem ended up being a slight air leak around the transfer case boot, combined with the noise/airleak at the sunroof, and it sounded EXACTLY like a bad bearing!

The shifter still has a slight vibration, and it does move a bit, but I can turn the bad bearing noise on and off at will by closing the cover on the sunroof (BTW, this is with the sunroof closed)
YMMV