Rear Diff Metal Flakes

[03_4R_LTD]

I know this topic has been discussed before, but I wanted to get opinions on my 2003 4Runner LTD. Bought it new, has 234.4k miles, service as per manual it's entire life. Never had a report of metal in the diff fluid.

All 4WD fluids were replaced at 198k miles. Since that time, I have moved, and towed a 6' x 12' dual axle trailer 4k miles - half of the miles loaded, half unloaded. Now in a new location, and had to find a new shop. Got a nice tour of the shop I selected, it was clean, organized, and I liked the owner.

Since I had done recent towing, I asked them to change all 4WD fluids, which they did except for the transmission - said it looked good and they saw no reason to change it. They reported metal flakes on the rear diff drain plug and a sheen in the fluid (no metal chunks or fragments), and recommended replacing the rear diff. No noise from the rear diff during test drive, and I've heard no noise.

I don't know if you have priced a rear diff replacement lately, but the frickin' numbers will make your eyes bug out. My inclination is to watch and monitor, change the fluid more often and see if the problem persists.

What do you guys think? I do have an 800 mile round trip planned in about a week to visit family over Christmas - would like to drive the 4Runner (winter road conditions) if you think it's OK to go that far?

 

[Syr4RinNC]

Just a moment...

I had some metal specks on my diff plug too - Im pretty sure thats why its magnetized as some metal specks are expected. If they saved the fluid you could have done an analysis of it.

Maybe just plan to change the rear diff fluid again when you change your oil next and see how it looks at that time

 

[xtremewlr]

Just a moment...

I had some metal specks on my diff plug too - Im pretty sure thats why its magnetized as some metal specks are expected. If they saved the fluid you could have done an analysis of it.

Maybe just plan to change the rear diff fluid again when you change your oil next and see how it looks at that time

I agree with this. Metal flakes in the diff fluid aren't surprising, nor are they cause to replace the entire rear differential. That's just ridiculous, especially if you have no noise and it still feels nice and smooth.

Do a drain and refill with the proper fluid (I personally like Redline 75W90 GL-5 gear oil) and don't worry about it. Do transfer case, front and rear diff fluid changes about every 30k miles and call it good.

 

[Buckaroo]

Totally agree with OP, with no other symptoms, no reason to replace. I think that was an irresponsible recommendation from the shop - careful with them in the future. As you suggest, monitor for diff related whine. If the whine appears or if 10,000 miles go by, change the diff fluid again and check condition. Should some kind of action be required in the future, would look at rebuilding or replacing with a rebuilt or used/junkyard diff. I think the tow rating on your truck is 5,000 lbs which isn't that high. Careful with that dual axle trailer loading so as not to exceed it.