2000 4Runner on 260K Rear Diff Fluid

[FD7683]

I have been nervous lately about my rear diff. Nothing wrong with it but I have never gotten around to changing the fluid on any differential on this truck and its been 15 years we've had the truck in the family with no knowledge of service. Also the rear differential is looking a bit crusty i'm in Ohio although the frame is "ok" the diff cover is looking real nasty due to the salt they lay here so its another reason why I haven't touched it.

What do you guys say? Should I change the fluid on it?

 

[T4R2014]

If you don't maintain it, it'll force you to maintain it in my experience. I would inspect the rear axle breather. This is more likely to cause a leak than fresh fluid will. Buy a can of PB Blaster surface shield and spray where crusty.

 

[talkstometal]

I am in the same situation. 270k miles. I almost changed the diff oil a few months ago but read something that made me glad I didnt. Was going to put synthetic in but read somewhere that a persons rear bearing failed shortly after. If I decide to change, I will put exact stock replacement, not synthetic.

 

[T4R2014]

My brutally honest take: All of these original, untouched rear ends need full rebuilds. Recoating, full diff rebuilds, new wheel bearings and brake shoes, new locker actuator, new ABS sensors. Then and only then can we not stress about remaining service life and repeat touch scenarios that waste money on labor. Just reversing the minimum 25 years of life taking course. I only say this because I'm just limping old stuff along. I got a deal on a used rear, thought about doing just the wheel bearings and running with it. But I'm gonna lose my mind if that unknown diff has a pinion whine.

 

[Twisted Sid]

Just change the fluid. Its not a hard job unless the drain and/or fill plug is seized. The new fluid won't mess anything up that isnt already on its way out from the lack of maintenance.
Its just bearings and gears in there.

 

[Malcolm99]

You would want to change it. If there is a problem or it is unknown rear diff, order a new one from ECGS, its not a big deal to swap a 3rd member and do axle bearings if the rear locker comes off easy, you'll need to return a core to them. I change my rear diff fluid every 30,000km as it gets the crap kicked out of it. You can also but new rear diff covers to weld on, doesn't look fun though.

 

[FD7683]

First time logging in since posting, this website is hard to use these days. Thanks for the replies everyone I will plan on changing it someday I know for a fact my breather is loose and working. May have to do 2-3 rounds of drain/fill over a span of a week. If I loosen the fill plug is there a chance I break the diff cover? thats what scares me and I don't have a welder!

 

[Twisted Sid]

Yeah, this site has gone to hell. Its kinda sad...

You're more likely to strip the drain/fill plug than something happen to the axle housing. Which is why you start with the fill plug before the drain. It should be 24mm or 15/16" 6 point socket. Dont use a 12 point. Id try giving it a test pull with a long ratchet/breaker bar and see what happens.

 

[phattyduck]

May have to do 2-3 rounds of drain/fill over a span of a week.

This isn't an automatic transmission. 90%+ of the fluid will come out when you drain (make sure the fill is loose first...). A single drain and fill every 15k-60k, depending on conditions, is all you need. Don't forget the transfer case and front diff too, assuming you have a 4WD.

-Charlie

 

[Endlessblockades]

Yeah, this site has gone to hell. Its kinda sad...

There are some site issues, but to be fair, it's working OK lately as long as you run an ad-blocker. I cannot imagine how many new owners come to this site without knowing that and never return......hwell:

 

[FD7683]

This website used to be so great until the owners let it run to the ground! I will plan on changing all diff fluid this year I will post what comes out thanks everyone! Great advice on opening the fill plug I may just rip it out with my 1/2 in impact lol.

 

[nissanh]

i went from conventional to RedLine (the best Diff fluid) full synthetic in my Land Cruiser and no bearing issues.