Hilux pinion bearing - how serious?

Jun 13, 2005
Borroloola, Australia
I've got a 1984 LN65 4WD hilux - the rear diff has been getting noisier and noisier over the last couple of months, mostly under load at medium to high revs.

Crawling underneath, it looks like oil is getting thrown out of the pinion gear seal where the prop shaft comes in, and there is a decent wobble developing there :eek:

OK, needs fixing I hear you say. Trouble is, I'm selling the old truck soon, and, although it's in pretty good shape otherwise, I don't want to spend a lot of time or money on it. The rear diff pinion gear bearing comes in twos, front and rear - the front one can be changed without any major dismantling, but to get to the rear one, the whole diff has to be pulled down.

So - is it always necessary to replace the rear bearing, or can I get by with the front bearing and the seal. Or on the other hand, could the truck run for years with a dodgy pinion bearing, and I'm getting het up about nothing?

thanks, Peter


Frame waxer
Apr 5, 2003
Southern NH
Dunno about down there, but in the states, open 4 cyl diffs with 4.10 gears are cheap, some people will just about give them away. You might toss a message up in the Wanted section and see what you get.

The other thing you could do is swap the diffs, put the front one with little or no wear into the rear axle. You'll spoil a bunch of gaskets and need about 4-5 quarts of gear lube, but other than that it's mostly labor.

To answer your question, when pinion bearings start making noise, it's almost always the bigger one inside the diff, since it sees more load than the outer one. And I disagree that you can get the outer bearing out without dismantling the diff. Yes, there is a SST shown in the manual for getting that bearing out, but that tool is really expensive and hard to find. Those bearings are in there TIGHT, you'll never pry it out. Besides, with the new bearing, you really should pop in a new crush sleeve and properly set the bearing pre-load.

A complete setup kit for this diff will run you about $100US, which is why I made the first 2 suggestions.
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