Hi guys,

We have a 2000 LS400. (~ 305k KM / 189.5k miles)

The other day, when we were getting the brakes serviced, our independent mechanic that services our rear brakes every year (Mobile mechanic), noticed and showed us the rear making quite the griding/metalic noise, when he turned the wheels around.

His opinion was that the rear differential is shot and likely not even worth fixing, given the likely cost and age of the car.
He figured the car might have another 12-18 months of driveability, before not being able to drive it.

Question: Is it worth at this point, even changing the rear differential fluid?
I bet it's never been done the ~ 22 years....

thanks,
Mike

 

I'd say "yes it's worth it to change it." Maybe $40 for the fluid and whatever $$ your mobile mechanic charges for the hour labor is worth it even if it does only last you another 12-18 months. Maybe the fluid has leaked and is low. Or, after 22 years it's just bad fluid. Either way, I'd do it.
I don't know if you're mechanically inclined at all but this is an easy job. http://www.lexls.com/tutorials/suspe...C%20or%20SAE90

 

Yeah, good point - how much further damage can happen, if it's already sounding squealing/grindy? I guess, may as well try it, if it can't get worse from new fluid.

 

Make sure to inspect the old fluid if the diff really is grinding you'll see metal flakes.

 

As the above, worth doing and to see if there are shavings in the fluid. That's about typical lifespan for a neglected rear differential.

 

I would have a different guy check it out, funny he didn't notice the noise last year. did he have both wheels in the air when turning the wheels ?

 

yeah it wouldnt hurt to swap the fluid (here are the few cases you do NOT have to use OEM fluids).

i also would get a second opinion. even if neglected the diff is a closed system that doesn't see big heat swings (unlike the engine), unless you had an unknown leak and the fluid level dropped significantly.

sound could also be the pads and shoes (yes the car has drum brakes inside the rear rotor hats for the e-brake) dragging making noise!

 

I have nothing to add other than to say:

Remember to change your diff fluid folks! Commonly forgotten about item. Owners manual says 4 years, 48k miles (it's part of the major service I think).

 

Nothing to add? Id say you added more knowledge to other people.
I'm actually thinking now about changing mine seeing how it's 29 years and 85K miles. And I'm doing the other work on my new (used) car. (When I get some ambition to work on it)
It aint much $$ for the fluid and would save alot in the long run.

 

Are you sure the noise was coming from the differential and not from the brakes dragging on the rotors?

 

I will second, or third, the idea of brakes, actually the E-brake shoes inside the rear rotors. With this many years, and that many miles, if they're original they're probably bad or sticking. Me and a couple other people have done them cuz of sticking. The hardware gets dusty and rusty to where the springs don't spring anymore. Especially if you don't use it often. I had a spring come off on my passenger side and was scraping inside the rotor, until it grabbed on something and then.........BAM.......clunk clunk clunk. The whole car was jumping so bad. It actually felt like a flat tire.
But I'll still say, for the price, you should still change the dif fluid.

 

Saw a repair video of one vehicle that the rear caliper mount bracket had been bent so it shifted into the rotor causing a constant scraping sound.

Video here:

 

I used some Valvoline Full Synthetic 75W85 or something along those lines about 3 yrs ago and it's been very quiet since over 16k miles