Forgotten fluids: 560SL differential fluid
 

Well I finally got around to changing the diff fluid on our 560 last night. I was astounded at the putrid sludge that drained out of it! I flushed a little gear oil through and then filled with new Mobil 1. The job is pretty easy but you have to get the car up in the air enough to get underneath, AND it must be level to allow the diff to be filled properly.

A 14mm allen driver is required for the job. No parts required, just gear oil (1.3 l).

My research says most if not all 560SLs have a limited slip diff - requiring "special fluid". Regular gear oil (I use synthetic, of course) can be used if a "friction modifier" is added...or just buy some gear oil that already has the stuff added. I didn't use any friction modifier yet...so far there is no chatter with the Mobil 1. If I notice anything I will just add it later.

This job is so easy there is no excuse to put it off - so don't!

best,

Dave
87 560SL

And whoa, it stinks!
 

The differential fluid in my '85 smelled so bad that I had to power wash the garage floor after spilling some. My wife wouldn't go in there. I threw out anything that touched the fluid. I never smelled such a foul stench since changing the oil in some old motorcycle forks.

Nasty old dinosaurs!

FYI, Gear lube is supposed to smell bad. This is because of its high sulfur content. I'll agree that I don't want that smell in my garage either.

I was once removing the front axle from an independent front suspension truck (an involved process), and I had a tub of gear lube that I'd already drained out of the axle sitting on the ground. While I was laying on the ground under the truck I put my foot into the old lube. Those leather shoes went right into the trash.

For the $5 gear lube costs, changing it is a good idea. You can also check for metal chunks which might be a sign of future bearing failure.

-Tad