w116 300sd Mercedes Differential oil
- Thread starter Gito
- Start date
Any 75w-85 or 75w-90 gl-5 will do
JHZR2
Staff member
I run 75w-90 in my w123 and w126 cars. I run amsoil svg in some, but have moved to supertech syn in most because this isn’t a very stressed situation, and I don’t put huge mileage on the cars.
AutoMechanic
Site Donor 2024
I buy the Pennzoil 75W-90 or occasionally will get the Royal Purple 75W-90 all brands will work though those are just the ones I use. It should work for that I would think.
Many of the gear oils that I'm finding at stores are for Limited Slip Differentials and I keep reading that LSD gear oils are no good for Non LSD (non clutch) differentials. I just finished installing the rear flanges (new bearings, races and seals) on my w116. Was able to tighten the special slotted flange nut within limits. I have a few more things left to do before I install the brake calipers and wheels back on the car.
1. Drive the inner seals little more so that the axles do not rub against the rubber part of the seal when at rest or when they are turning with the flange. Little tricky. Have to find the correct size (Circumference) socket to carefully drive it in so more.
2. Install the axles
3. Differential mount and differential cover
4. Fill Differential with correct gear oil
1. Drive the inner seals little more so that the axles do not rub against the rubber part of the seal when at rest or when they are turning with the flange. Little tricky. Have to find the correct size (Circumference) socket to carefully drive it in so more.
2. Install the axles
3. Differential mount and differential cover
4. Fill Differential with correct gear oil
JHZR2
Staff member
I don’t know about no good.
In fact, I’m not sure it’s that easy to find a syn diff oil that doesn’t have some level of LSD modification.
My understanding Was that the LSD additive affects oxidation stability. Something that is more of a concern with conventional lubes, less of a concern with syn.
A diff oil change is one of the easiest jobs to do, though the MB diffs tend to seize the drain plug pretty good, requiring a cheater bar. So to me it’s straightforward to just do it on a schedule with ATF, and do it time based on low mileage cars. The inclusion of LSD additive doesn’t bother me much at all.
All that said, I did read some anecdotal comments that conventional gear lubes cling and protect better in differentials. No idea if that is true. If it is, then running a conventional 80w-90 is a good choice assuming the climate allows. Conventional is what it was delivered with anyway...
In fact, I’m not sure it’s that easy to find a syn diff oil that doesn’t have some level of LSD modification.
My understanding Was that the LSD additive affects oxidation stability. Something that is more of a concern with conventional lubes, less of a concern with syn.
A diff oil change is one of the easiest jobs to do, though the MB diffs tend to seize the drain plug pretty good, requiring a cheater bar. So to me it’s straightforward to just do it on a schedule with ATF, and do it time based on low mileage cars. The inclusion of LSD additive doesn’t bother me much at all.
All that said, I did read some anecdotal comments that conventional gear lubes cling and protect better in differentials. No idea if that is true. If it is, then running a conventional 80w-90 is a good choice assuming the climate allows. Conventional is what it was delivered with anyway...
LSD oil can be used in non-LSD diffs 
Super Tech 75w90 will be fine
Super Tech 75w90 will be fine
