heavy gear oil in t-case

[toyNG]

A few months ago I installed 4.7 gears in my t-case. The gears are noisier than stock, making a humming or buzzing sound. The sound isn't super loud; it's not even noticeable with the radio on. Problem now is that my radio got stolen.

The noise from the gears isn't terrible, but I was wondering if it'd be a good idea to quiet them down by using thicker oil. The Trail Gear website calls for 80-90 oil with the 4.7 gears. Anyone see any problems with something like 80-140? I figure I might get slightly lower MPG, but that's not really a big deal to me, since the truck isn't my daily driver. Btw, summer temps here are in the low 100s, and winter lows are in the 40s. just wondering what your guy's thought were

[04 Rocko Taco]

I would think with your temp ranges, the heavier oil would be fine, but I'm in no way claiming to be an expert. I don't really see any problem with it. I would just make sure to monitor your mpg's occasionally, and watch the t-case temps, and check it every now and then to make sure it looks likes everything is going "smoothly" and you're all set.

[4x4mike]

Is there are break in time for the new gears? Maybe they will get quieter with time.

[AxleIke]

I've run numerous oils in the case and tranny. Heavy oil sucks in the cold, but overall, is nicer, and generally better for shock resistance, at least from what I've read on the forums.

Heavy oil in the tranny just plain sucks. I think you'd be fine with an 85-140 blend in the case.

[toyNG]

Is there are break in time for the new gears? Maybe they will get quieter with time.


I think so. I've put about 1000 miles or so on them so far. I noticed less noise after the first 100 or so miles, but not much difference after that. I spoke with Trail Gear and they said that it is completely normal for the gears to be louder than stock.

Since I live in So Cal, I think I'll probalby be fine running something like 80-140.

[Obi..]

Drain things out, and if you like do the blend out like AxleIke recommended, at the same time when you drain it, use a cleaned out milk jug and see what's resting in the oil. From my experience, once you change the break-in fluid out and get anpother 1500-2300 mles on it the thing quiets down considerably. As long as when you milled the case to clear the 4.7 you got it just right you should be fine, if you went a little tight on the clearance, realize it may be holding flow back. Am I making sense?

[Scuba]

^^ Clear as mud ;)