Anyone using Mobil 1 75/140 gear oil?

[pcosens]

Toyota did my last gear oil change - put Toyota 75/140 synthetic in the front diff and trans case, unknown viscosity oil went in the LSD rear diff (no corresponding toyota PN for gear oil #s listed on invoice) They did add Friction Modifier - unknown brand.

Questions are: ('03 4x4 AC 4.7, factory LSD - cold winter exposure)

1 Use Mobil 1 75/140 at all? Advantages? Disadvantages?
2 Use in front diff and transfer case only?
3 Mobil 1 75/90 for the rear diff? I will still use an additional Friction Modifier.

I appreciate all input . . .

Paul

[KLS]

Are you sure? I think 75W-140 in temperate or cold temperatures might be too cold to flow properly to all the bearings. It could "channel" and not lubricate as it should. It certainly is too heavy for the front differential and transfer case. I'd use it for the rear in very hot weather, although 75W-90 does fine.

My choice for the front, rear, and t-case would be synthetic 75W-90. Most GL-5 gear oils already have the limited slip additive, and more is not better. I didn't add more and my LSD is smooth. Only add more, a small amount at a time, if you have chatter.


Ken

[mitchr]

I use Mobil 1 75W-90 synthetic in mine.

[pcosens]

Originally Posted by KLS

Are you sure? Ken

Yup! It's a valid Toyota PN, is currently in my Front diff and Xfer case. God only knows what they (toyota tech) put in the rear. Not concerned about cold performance - 75 is plenty thin for cold I see.

Mobil 1 web site indicates this is a "Premium" product for Light trucks, exceeds GL5, has EP rating (of sorts).

Anyone using 75/140 of any brand? Ford and Dodge sites (web search on 75/140) seem to indicate that these manufacturers are moving to 75/140 - alot of owners complaining how hard it is to find source other than dealer at $$$$$.

FWIW - I was at a Toyota dealer in upper NY state yesterday - they use NAPA 80/90 DINO gear oil in all of their fr/r diff services! Hmmmm

P

[sequoiasoon]

I don't recall for the front but I know the '03 Sequoia has and calls for 75/140 synthetic for the rear.

[pcosens]

UPDATE: Back from the original dealer . . . .

Toyota PN 00289-75140 is a synthetic 75/140 gear oil, Toyota formula (saw the bottle) - the Master Tech insists that Toyota now specs this for the FRONT differential, as the loads/temps/wear they were seeing motivated a shift from original spec oil.

The transfer case appears to use just about any old oil - Tech says 75/90 synthetic. Oddly he questioned the use of 75/140, even after acknowledged that he used it in my transfer case last service??? (same master tech)

REAR diff is special . . . Toyota PN 00009-00028 IS a real toyota number - the bottle has NO INDICATION as to synthetic or not - no viscosity rating for that matter. Bottled by Toyota Canada. I bought one, will post image ASAP to see if anyone (lurking Toyota official types) might be able to shed some light on the nature of this beast. My guess is DINO 80/90. The Tech was adamant that this be used in the rear diff, with a friction modifier.

Friction Modifier, PN C8AZ1-9B546-A, is a FORD product!!! I laughed right out loud.

I'll post the image of the mystery gear oil after dinner.

P

[pcosens]

removed post.