Differential Oil 75w-90 LS

[98LXand99LC]

I have lots of this gear oil (Mobil 1 Synthetic LS) for my ‘99 Land Cruiser, can I use it for my 2015 LX’s Differentials and transfer case?

 

[bloc]

I have lots of this gear oil (Mobil 1 Synthetic LS) for my ‘99 Land Cruiser, can I use it for my 2015 LX’s Differentials and transfer case?

Should be fine for your diffs even if it’s a bit thicker than recommended, as they have no yellow metal.

Your transfer case specifies straight 75wt and in 2010 or 2011 a syncro was added that may be why this is the case. GL-5 fluids can attack yellow metal parts. The 75wt is probably GL-4, and the OEM stuff has some strange properties.

Lots of discussion on it and a less expensive alternative in this thread: $80/liter transfer case oil - https://forum.ih8mud.com/threads/80-liter-transfer-case-oil.1059141/

 

[hankinid]

M1 75W-90 is just fine in the diffs.

Toyota says 75W in the TC. Toyota 75W runs > $30/qt and you need 2.

The only other 75W that meets Toyota's specs is from Ravenol. 2 qts shipped to me runs a little over $40 and takes about a week to get here.

The oil bottles have a hose that extends from the cap and it's long enough to fill the diff without spilling...i.e. no funnels required.

Link here... Go to the 2nd page when the link opens and it's the first item on the page.

 

[montegofd3s]

I am running Mobil 1 Synthetic LS in the TC and diffs. The "LS" is just stating that it can be used with or without a LSD. They contain a friction modifier to allow clutch packs to function properly and "slip," but all things being considered they both lubricate bearings, shims, etc all the same. Since open diffs don't have clutches this makes no difference (still lubing all parts the same), but it just isn't a necessary additive package needed.

 

[linuxgod]

I would not use the LS fluid. The LS stuff is typically for diffs with a limited slip. We have open diffs, and sometimes the friction modifiers in the LS additives can cause issues. Regular 75W-90 Mobil 1 is pretty cheap, probably $60 for enough to cover your diffs (you need about 6.5 quarts).

I recommend Ravenol 75W for your transfer case. It's not an LF fluid, but it's "close enough". I've heard that Royal Purple makes a 75W that is actually 75WLF-compatible now too, but I haven't tried it. The Ravenol fluid will set you back $20.

 

[montegofd3s]

and sometimes the friction modifiers in the LS additives can cause issues.

How so? An open diff is materially the same minus the clutch pack.

 

[linuxgod]

How so? An open diff is materially the same minus the clutch pack.

It looks like Mobil1 only makes one 75W90 now, which is the LS fluid. So maybe this is in fact fine to run. My knowledge and experience with LS additives is quite possible a couple decades out of date. Mobil used to make LS and non-LS versions of their 75W-90 and under those circumstances I'd have to ask why they'd ever make two different versions unless there's a reason to NOT use the LS additive.

(Anecdotally I had some rear diff issues in an old Mustang I owned years ago, which seemed to track back to using a synthetic diff oil with a LS modifier. Going to a straight dino oil resolved it. My mechanic at the time believed it was because of the LS additive in the oil, though it could just as well been the synthetic oil itself. This was in the 90s so ages ago...)

 

[montegofd3s]

Gotcha, that makes sense. I imagine at one point there was a price difference as well since the LS additive package wasn't included, but synthetics have become so advanced that it probably doesn't makes financial sense for them to split the two. Since we were discussing this I went to look up amsoil's recommendation to compare, and they suggest their 75w-90 Severe Gear oil in both our TC and diffs which are LS rated also. Just adding that in for anyone searching in the future.

 

[98LXand99LC]

Excellent, good news on the diffs. Will get the proper TC lubricant.