Rear diff oil for a 1988 Mercedes 420SEL?

[Lumberg]

Hi all. Just lucked into this beaut and the manual simply states "Hypoid gear oil SAE90, 85W90."

It's the same manual as for the 560 SEL and SEC, and for those cars the rear diff oil is "Hypoid gear oil SAE 90 for limited slip differential"

So I think it's safe to assume that the limited slip additives are not necessary.

I'm mostly interested in smooth low-temperature operation and low friction. So I suppose I should just look for a 75W90 with the lowest low-temp viscosity?

 

[MolaKule]

I recommend a synthetic 75W110 or a bio-synthetic 75W90.

 

[Lumberg]

Why the 110 upper bound? Cos it's an older car and it protects better?

 

[HTSS_TR]

M1 75W90 is the fluid for your car

 

[VK56VD]

Amsoil Severe Gear 75w-90

 

[Gary Allan]

Originally Posted By: Spartuss
Amsoil Severe Gear 75w-90


Yep ..

 

[Doug Hillary]

Hi,
Lumberg - If the car has a LSD a MB235.7 specification fluid is required (Part No 001 989 1703). This should be checked as a priority!

If no LSD is fitted a synthetic 75W-90 GL5 fluid is required - the Brand is not important. Mobil, Shell and Castrol's products perform well in these applications