Fever

I was told if I put 5.29 gearing in my 1990 4runner the gearing is too low and the oil will heat up and the gearing will only last 1 year. I heard this from my 4x4 service center. I am installing Youkon gears which are made by TRD for Youkon. (Good quality stuff) Should I worry about this? I was thinking of expanding my oil capacity by cutting the round punkin off the back of the rear and welding a 2 inch extention to the back of the punkin. This will give me just over 1 quart more lube. I was also thinking of running a synthetic gear lube. Any body have any suggestions or experience with this?

mt_goat

What size tires? What transmission, auto or 5 speed?

DeathCougar

iTrader: (23)

Depending on your tire size. As long as you dont run lower than 35" tires, you will be ok. If you are worried about it though, just go for 4.88 gears. My buddy is using them on his 85, and they work great. Not to mention that some '95 4Runners came stock with 4,88 gears. The extra .50 ratio is not worth destroying your gears, if that is really what happens.

Flygtenstein

I have 5.29's with 33's and have been running them for better than 20k miles with no problems.

Use a good synthetic gear lube and make sure that it is checked regularly if you drive in dusty/wet conditions.

They got hot as hell when I broke them in, but that is how the break in works. The axle is much cooler now even after several hours at highway speeds.

mt_goat

I ran 5.71 gearing with 33" BFGs in an auto tranny and they lasted 4 years/ 40000 miles before the pinion gear started making noise. But they were Genuine crap gears and I didn't know anything about properly breaking in new gears and did the worst thing you can do to new gears, I hit the highway at 75 mph for 130 miles without stopping. Plus I didn't change the gear oil at all for the first 25-30K miles.

toy283

I seriously doubt TRD cuts any gears at all. Toyota doesn't even cut the gears found in their products. Just about all the gears for all Japanese brands of vehicles are cut by Aisin.

Fever

Thank you for all the input. The stock gears are 4.55 with a 3.slow and automatic and 33's. It sounds like I will nave no problem. You helped me save time since I do not have to increase my oil capasity. Thanks again.

mt_goat

Oh yeah no problem, my truck came from the factory with 4.88 and 31" tires. 5.29 and 33" tires are about the same as my stock set-up. The auto OD gear will drop your RPM's way down. You don't want any higher gearing than 5.29 with 33's and an auto.