Differential Plug Size
 

All,

I had the new SL up on blocks to take the rims in to get new tires and noticed oil on the rear dif. Wanted to check the level but do not have the correct allen (hex) wrench (have every size but) Does anyone know the right size?

Thanks!

John

88 560SL
01 ML320
92 400E (sold)
97 F150

The differential has two plugs, a drain plug and a fill plug. They both need a 14 MM Allen wrench. They could be real tight so use a socket type that goes on a breaker bar. Loosen the top one first, then go for the drain. This way you don't drain the fluid, then find that you could not get the fill plug loose. I believe the lubricant is 80 weight gear oil. Get the stuff with the additive in it for limited slip differentials. The 560 SL has a limited slip. You will need two quarts, as one will not be quite enough. Warning: the old lube will smell bad, don't get it on your clothes or garage floor.

Appreciate it!

I agree, that is the worst smelling stuff on a car!