75w-90 on Diffs and Transfer Case

Is anyone using Mobil 1

$26 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 on both the diffs and the transfer case, and if so is anyone running into any problems? I know it states different weights in the manual but clearly everyone here has a lot of real world experiences.

 

never hurts to stick to factory oem manual requirements

not everyone has the same load on their driving............whereas i might use a product

have NO issues .......i drive hiway a lot !!!

my vehicle does not have a lot of cycles on ALL components = less wear& tear

so my answer might NOT apply

check out RED LINE !!!!!! they have More Driveline Lubes than anyone

 

Ok cause all I've found was that the recommended 75w-85 is just better for fuel economy...

 

I have enough experience to stick with OEM specs. You do you.

 

The difference between 75w-85 and

$26 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 is so insignificant as to be functionally zero. Run what you want. The Mobil will work great

 

what experiences do you have if you don't mind me asking. Thats why I put the question up on this forum.

 

For the diffs, https://www.redlineoil.com/75w90-gl-5-gear-oil

For the transfer, https://www.redlineoil.com/mt-lv-70w75w

If your rear diff is whiny/noisey? this will help, https://www.redlineoil.com/75w110-gl-5-gear-oil

And FYI, Mobil1 is a ghost of what they once were. Many folks love their stuff, I think they've gone to sh*t(imo).

 

And better fuel economy is bad how?

 

After trying all the usual brands, I stick with adrenochrome. Way better mpg.

 

I know the guys who specified the lube know their shit better than me. Again, you do what you want but I trust the engineers who designed it.

 

That’s an appeal to authority, not an experience that informs your opinion.

Engineers often make decisions based on priorities different than the end user. MPG standards might change a lube standard at the expense of severe-duty wear protection, for instance. If you weigh variables differently than corporate does, following the engineer’s recommendation might not yield an optimum result.

75-85 and 75-90 are functionally identical and using one or the other won’t harm anything

 

Prove it. They can. You can't.

 

As much time as I spend working closely with engineers, they are given a set of parameters. When what they have in front of them meets said parameters their job is over and it doesn’t matter if it’s not practical. All they can prove is it met that set of parameters. I bet most of them nowdays are meet epa mpg standards, make it past warranty. Hence why they still have that garbage roller bearing in the diff instead of a bushing.

 

Yes. Just changed to 85-140 in my front diff (ECGS needle bearing mod). Don't over think it.

 

I run Redline

$26 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 in both diffs with no problems, and will run 75W Ravenol in transfer case when I change it. The sooner you change your diff oil the better. Both of my diffs were under filled by as much as 30% from the factory. I also do not have noisy rear diff probably because I filled/replaced mine early on.

 

Been running 75w/90 Redline in my front and rear diffs for 20k miles without any issue. It definitely helped my rear diff quiet down a little bit. When I change them again here at 60k I am going to move to the 75/110 to see if it helps quiet it down some more unless I regear then I'll run the dino oil instead of synthetic per ECGS.

 

You can’t prove that the engineers’ recommendation is better than 75w90 for the goals of the OP. You say “they can,” but you don’t even know the design compromises made.

Look, I’m all for going OEM. But there are lots of times where the OEM recommendation is at odds with the goals you’re trying to achieve. We don’t all run only stock size wrangler Kevlar garbage tires…because they don’t meet our needs/wants. We don’t all run stock suspension bushings, shocks, diff bearings, cab mounts, alternators, batteries, bumpers, brake pads, and a thousand other things…because they don’t meet our needs/wants.

All of that aside, there’s literally zero functional difference between 75w-85 and

$26 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90. As long as it meets the GL spec, which it does, it’s not going to harm a thing. Engineering is a lot less precise than that.

 

Same goes for engine oil. They make us run 0w-20 for fuel economy when 0w-30 is a better oil for trucks, especially working trucks, IMO.

 

some think themselves ' clever ' splitting hairs over minutiae

rear diffs when thousands o miles b4 ' synths '

unless severe conditions exist in Ur normal daily environs

thinkin extreme conditions on other continents + the ever present ' just n case ' IS rather Futile !!!

 

I presume this is based on lab analysis of a large sample size? Because otherwise I’d like to know how this statement could be made...