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I’m getting mixed info searching through the forums and I just wanted to be sure. Is the correct oil for both front and rear diffs 75W-85 gear oil MB-Approval 235.7 & 235.74? Thank you for the advice.
Called dealer and they did confirm 75W-85 was the correct oil. It did take him a while to figure it out, almost seemed like he wasn’t too sure either. The dealer wanted $90 per litter bottle. I refuse to pay that lol. I used https://operatingfluids.mercedes-benz.com and found Fuchs TITAN SINTOPOID FE 75W-85 as an approved fluid for 235.7. Only found a couple of websites that sold it. Got 3 bottles for $85.78 after tax and shipping. Cheaper than just 1 bottle at the stealership. That 75W-85 seems like a pretty uncommon weight. I wonder if 75W-90 would be just fine?
You’d be ok with 75W90 in the rear diff, if I’m not mistaken front is 85W90.
I used LiquiMoly 85W90 for the front and Valvoline 75W90 Synthetic in the rear.
Assuming you don’t have the Off-road package with LS differential.
You’d be ok with 75W90 in the rear diff, if I’m not mistaken front is 85W90.
I used LiquiMoly 85W90 for the front and Valvoline 75W90 Synthetic in the rear.
Assuming you don’t have the Off-road package with LS differential.
Where are you getting this info? I called the dealer and they said 75W-85 for both so that’s what I got. It’s gear oil so I’m sure it’s not a huge deal if it’s not the exact weight but I would like to get the correct spec oil.
The reason the dealership took forever is because you are the first guy in the last 17 years to ask. He had to take some time to call over his parts counter buddies to discuss whether to mess with you.
The differential is big steel gears inside a big aluminum housing. That's it; there are no little pixies inside, no unicorn urine lubricating the gears.
If you go too light weight, like really light, you might get to the point of suffering excess gear wear. Or the oil might foam up. If you go too heavy, fuel economy will suffer, and maybe the diff housing will get hot.
The manual just says "Hypoid Gear Oil". It is standard oil for hypoid gears (not hypoid oil for gears, lol).
For what it's worth, it says the same Hypoid Gear Oil for the limited slip (locker?) differential, only more of it.
The engine cares what viscosity oil is in it, and for service intervals cares what type of oil. The automatic transmission has clutches and stuff in the oil, along with solenoids, and is a mighty expensive subassembly, so in both those cases I'd stick to recommendations. But the differentials? Nothing special therein.
The reason the dealership took forever is because you are the first guy in the last 17 years to ask. He had to take some time to call over his parts counter buddies to discuss whether to mess with you.
The differential is big steel gears inside a big aluminum housing. That's it; there are no little pixies inside, no unicorn urine lubricating the gears.
If you go too light weight, like really light, you might get to the point of suffering excess gear wear. Or the oil might foam up. If you go too heavy, fuel economy will suffer, and maybe the diff housing will get hot.
The manual just says "Hypoid Gear Oil". It is standard oil for hypoid gears (not hypoid oil for gears, lol).
For what it's worth, it says the same Hypoid Gear Oil for the limited slip (locker?) differential, only more of it.
The engine cares what viscosity oil is in it, and for service intervals cares what type of oil. The automatic transmission has clutches and stuff in the oil, along with solenoids, and is a mighty expensive subassembly, so in both those cases I'd stick to recommendations. But the differentials? Nothing special therein.
Yeah you are right, I am overthinking it. I’m just peculiar about things like this and want to make sure I use the right fluids 😂 I’m going to stick to the oil I bought and stop thinking about it.
Yeah you are right, I am overthinking it. I’m just peculiar about things like this and want to make sure I use the right fluids 😂 I’m going to stick to the oil I bought and stop thinking about it.
I mean, if you change the diff oil twice, you are getting amazing life out of the truck. So it won't break the bank to use even the MB branded stuff.
I post essays like this mostly for other people's sakes, so they don't give themselves indigestion worrying about it.
here at MB dealer in Houston, they recommended:
PrecisionParts API GL-5
Ultra-Guard LS heavy Duty
Full Synthetic Gear Lubricant
SAE 75W-140
PN PP75364
BG
I mean, if you change the diff oil twice, you are getting amazing life out of the truck. So it won't break the bank to use even the MB branded stuff.
I post essays like this mostly for other people's sakes, so they don't give themselves indigestion worrying about it.
I appreciate it. I just bought the vehicle with 130,000 miles and I’m just doing all of the fluids that haven’t been done. I shouldn’t have to worry about the gear oil again during my ownership after changing it.
Where are you getting this info? I called the dealer and they said 75W-85 for both so that’s what I got. It’s gear oil so I’m sure it’s not a huge deal if it’s not the exact weight but I would like to get the correct spec oil.
I honestly cannot remember where I got that info, its been about 3 months since I changed the diff oils, it was the hot topic back then for me lol
But like Eric mentioned, nothing special in the diffs and as long as you are within the reasonable weight, then you are fine, if I used 85W90 in my diff and you are using 75W90, the difference is almost non existent.
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