‘02 4 Runner Rear Diff

[Gebo]

Rear end started whining under acceleration so I decided to check fluid. It was low and black as tar with many small chunks of metal on drain magnet. The drained fluid was so pretty with the gray powder swirling around in the catch container.

My rear diff ended up 1 qt shy of fluid. Either it leaked out in 500 miles or my mechanic made a bad mistake.

Replaced fluid and still have whine. Only bad at 60 mph and above.

How bad is it?

 

[JeffKeryk]

It seems as though you would see evidence of a leak. When was it serviced? Sounds like someone messed up.
I have serviced numerous Toyota differentials; the fluid never looked too bad. But then again I did regular services.
Good luck.

 

[Barkleymut]

I bet you can drive it for years before it gets really bad....you said your mechanic made a bad mistake? Was it recently serviced?

 

[Gebo]

I gave him 3 qts of diff fluid. 3 is plenty. Serviced about 500 miles ago. No evidence of leaks.

All I can figure is he forgot 1 qt. IDK

 

[Gebo]

I have serviced all my diffs and never saw this. It appears the fluid got really hot.

 

[JeffKeryk]

I have serviced all my diffs and never saw this. It appears the fluid got really hot.

Wow... Filling it until it runs out ain't exactly rocket science.

 

[drtyler]

Wow... Filling it until it runs out ain't exactly rocket science.

Is this the same mechanic that did the timing belt on your Lexus LS400 and failed to tighten the cam tensioners, or mechanic #2 that cleaned up that mess?

I might drive a while and see how it goes, then change the fluid again to check for metallic debris. I would also check for leaks, it just doesn't seem that an experienced mechanic would under fill a rear diff.

 

[atikovi]

Rear end started whining under acceleration so I decided to check fluid. It was low and black as tar with many small chunks of metal on drain magnet. The drained fluid was so pretty with the gray powder swirling around in the catch container.

I gave him 3 qts of diff fluid. 3 is plenty. Serviced about 500 miles ago. No evidence of leaks.

All I can figure is he forgot 1 qt. IDK

Why did you have a mechanic do it if apparently, you can do this yourself? One qt low for 500 miles shouldn't damage anything that wasn't already on the way out.

 

[The Critic]

Rear axle bearing seals are probably leaking. Pull the drums; I bet your shoes are soaked with oil.

If the diff already makes noise and you saw evidence of metal, it is probably toast.

 

[Gebo]

Why did you have a mechanic do it if apparently, you can do this yourself? One qt low for 500 miles shouldn't damage anything that wasn't already on the way out.

He was welding the rear replacement cover on for me. I don't weld. I gave him the 3 qts of gear oil to add after he got it all back together.

 

[Gebo]

Wow... Filling it until it runs out ain't exactly rocket science.

I know, I know......

Is this the same mechanic that did the timing belt on your Lexus LS400 and failed to tighten the cam tensioners, or mechanic #2 that cleaned up that mess?

I might drive a while and see how it goes, then change the fluid again to check for metallic debris. I would also check for leaks, it just doesn't seem that an experienced mechanic would under fill a rear diff.

This was a welder.

 

[Gebo]

Rear axle bearing seals are probably leaking. Pull the drums; I bet your shoes are soaked with oil.

If the diff already makes noise and you saw evidence of metal, it is probably toast.

My Lexus Service Manager said if it leaked 1 qt in less than 500 miles, I would have no problem seeing the gear oil.

 

[Gebo]

I've driven it 200 miles today and about 100 miles yesterday and am gonna check the fill tomorrow if it's "warm,"

 

[Gebo]

Refresh memories

 

[drtyler]

Refresh memories

It's possible that it was not re-assembled correctly.

 

[Gebo]

Well, the fluid is still full today. I'm sad. It appears he only put in 2 qts and I ran it 1 qt low. Could this have caused the fluid
to turn black?

 

[Gebo]

It's possible that it was not re-assembled correctly.

I would figure anyone could remove and replace the rear end. There are no adjustments are there?

 

[Gebo]

I am gonna fix it. $1200 for the Toyota OEM. Mine is the 4.10. (They used 3 different ones that year)

I guess I can't make a decision until we tear it down.

 

[D60]

I am gonna fix it. $1200 for the Toyota OEM. Mine is the 4.10. (They used 3 different ones that year)

I guess I can't make a decision until we tear it down.

If the fluid was as bad as you say in Post #1 do the wheel bearings, too....or at least inspect them closely.

Those are gobs of fun, I built a special jig for my 50T press years ago to do an '02 Taco

 

[CB22]

Rear end started whining under acceleration so I decided to check fluid. It was low and black as tar with many small chunks of metal on drain magnet. The drained fluid was so pretty with the gray powder swirling around in the catch container.

My rear diff ended up 1 qt shy of fluid. Either it leaked out in 500 miles or my mechanic made a bad mistake.

Replaced fluid and still have whine. Only bad at 60 mph and above.

How bad is it?

Was it good oil? maybe your mechanic kept it for his own ride. My 2020 Tacoma was 1/2 quart low from the factory.

I put Amsoil in the front/rear diffs at 5000 miles.