Mechanics

TOYOTA 4RUNNER RUST PROBLEM

1997 Toyota 4Runner • 89,000 miles

The 'Diff' is very rusty. What should I do with it? Repaint with anti-rust or change the whole thing? What is the risk if not changed quickly?
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Kbagiomea
February 6, 2013.



Why do you care if it has rust on it? That is typical on any car more than six months old up here in Wisconsin where we throw a pound of salt on an ounce of snow. Am I missing something?

Caradiodoc
Feb 6, 2013.
I have just bought this car second hand from Japan.
The rust from the diff is actually coming off in flakes. Do I wait for a hole to develop before I start to worry? Any way to slow the rusting process down is what I am asking the experts for. I am a lay person when it comes to vehicle repairs and stuff.

Tiny
Kbagiomea
Feb 7, 2013.
You still haven't described anything we don't see here in the northern U.S. Every day. I've seen the huge rust flakes I think you're seeing, and it is almost unheard of to have a leak be the result. To prove it to yourself, tap on it with a hammer. There's no pressure on the housing when it's in operation so if the hammer doesn't cause a leak or even dent it, driving it won't either.

After thinking about it a while, there are two different styles of differential housings. Some have a stamped steel cover that is relatively thin but even those rarely leak. I've never replaced one. I think your truck has a solid housing and the differential assembly drops out toward the drive shaft once that is unbolted. If that's what you have, you can definitely stop worrying about that rust. That steel is over 1/8" thick and will never rust through. I have a couple of those axles here from cars that were driven in salt for over 30 years. They're ALL rust and scale from top to bottom, ... But they don't leak.

Gee, it's nice to give good news for a change!

Caradiodoc
Feb 7, 2013.
Thank you for the reassuring piece of information Caradiodoc. Now I can breathe a sigh of relief and relax a bit while driving the vehicle. Just as patients worry about a lump in the neck, so do car non-experts like us worry about such signs in a vehicle. Nice to hear from the doctor.
Best wishes.

Tiny
Kbagiomea
Feb 11, 2013.