Mobil 1 75W90 LS Diff Fluid?

I’m about to change the diff fluid on my 4Runner, the first I’ve ever owned. It’s a 2022 and I bought it brand new so I’m taking advantage of me being able to dictate its entire service history to my standards. It currently has 2000 miles on it and I’m going to change the rear diff fluid to get rid of any break in material that may be floating around in there. Probably unnecessary but I have a week off for the holidays and it’s cheap maintenance. I’m looking at using Mobil 1 75w90 LS since it’s readily available at all the local stores near me. My service philosophy with this 4Runner is based around doing maintenance early and often rather than seeking the highest quality fluids available. Is this Mobil 1 diff fluid a good one to use? I also will do the transfer case eventually, can I use this as well for that? I owned an F150 before and Ford was very adamant about using a very specific type of transfer case fluid so I was wondering if the transfer case in 4runners were picky with what fluid goes in it.

 

Literally no reason to do this.

 

Any off the shelf fluid of the correct viscosity will work. But yes, no reason to change so early.

 

Front, t-case, rear are all fine with any high quality synthetic GL-5 75w90. Valvoline is typically available locally in the the bags with a nozzle which makes it super convenient, even Walmart tends to stock it.

 

Off the top of my head, isnt the LS for limited slip diffs? Double check that before pitting it in.

You can put in incorrect oil Especially for the transfer case, which I believe has synchros that can be damaged by the wrong additives.

 

Check this out for your diffs and t-case. For what it’s worth, I have talked to the service department at two of our local Toyota dealers and neither one use the 75W oil in the transfer case. Both said they use 75W-85 or 75W-90 that they buy in bulk.

https://youtu.be/3le9ZT5HUlk

 

When you actually do the work, do yourself a favor and pick up a fluid transfer pump. When I changed mine, I picked one up at a local discount store with a small tool department for about 8 bucks.

I dumped the quart bottles of fluid into a clean one gallon container, and used the pump to transfer from that bottle to the diffs and transfer case. Made it so much easier than trying to squeeze the bottles in my hand.

If I recall correctly I used Mobil 1 for mine, I don't think I grabbed the one with the limited-slip additive though.

 

It is not cheap maintenance if you use genuine fluid and it is a waste of time. I will never understand the eagerness to change fluids on this forum.

 

You are correct that the LS indicates it has additives for limited slip differentials but my understanding is that you can use diff fluid with friction modifiers in an open diff but you will cause issues if you use diff fluid without friction modifiers in a limited slip diff. I couldn’t find the non LS Mobil 1 fluid in any of my local part stores which makes me think they only offer the fluid with the friction modifiers since having it won’t cause issues in both scenarios but not having it can cause issues. If anyone knows better, please share since this was part of why I was asking about this specific fluid.

 

Appreciate all the replies. Changing the fluid was easy, only took about 30 minutes. I’m really glad I changed it early since there was about a half inch of metallic grit on the magnetic drain plug. For those of you who say there is no reason to do this, what is different about the gears in the differential as it comes from the factory compared to having new gears installed when regearing? Are they polished before assembly at the factory? Every shop that installs gears recommends changing the diff fluid after break in within 1000 miles or so. Why wouldn’t that apply to a fresh vehicle off the assembly line? This was my thought process for changing it early. Even if it’s completely unnecessary, it couldn’t hurt.

 

The magnet picked up all the shavings. There wasn't any more in the fluid.

 

i changed mine at around 15k miles because I heard a really light whine under light throttle. Still does it, but at least i got clean fluid.

By the way, maybe it’s age causing me to forget, but I might have gone through the same thoughts you did, because I found a bottle of the stuff i used, and it was, in fact, the same LS mobil stuff you used lol

 

I did the transmission, transfer case, front and rear axles fluid change at 15,000 miles on my 4runner. My recommendation is not to do the front axle or transfer case because when I drained them out it was like new. The rear axle oil and transmission definitively needed to be changed! I am coming from a 08 FJ Off-Road, which I sold it with 200k miles, to my 18 4runner, so I been thru all the gear/transmission oil changes. BTW the dealer, which I know many mechanics who work there, uses bulk fluids due to the cost and they are not going to stock all kinds of required fluid for every Toyota car/truck. They did tell me to make sure you use the correct Toyota 75W transfer case oil for our 4runners since the internal metals used are different from my 08 FJ and 18 4runner transfer case. Just my 2 cents.

 

If you do water crossings frequently on your off-roading trips, its a good idea to replace the oil.

However, if you are tactful enough, you can pull the top bolt and check for the chocolate milk. Otherwise, probably best to just do the diff's on their regular service intervals.

EDIT: As whipper already mentioned, your magnetized drain plug is going to catch all of the break-in shavings.

 

I did the rear diff at about 28,000. Fluid was in need of a change.

Transfer case fluid looked new at 28,000. Did not touch the front.

I used genuine Toyota fluids.

 

To help me understand, for a Part-Time 4WD system, does any engagement of the transfer case occur 'outside' of when the vehicle is engaged in 4H/4L? Would the same apply to the front differential?

 

There is no engagement of the front diff from the transfer case unless selected. The front driveshaft does not rotate unless engaged. But the transfer case is transmitting power from the transmission to the rear diff all the time.

Another reason I did not touch the front diff fluid was I had the diff replaced under the TSB and the fluid is relatively fresh. I expect it to look good when I eventually change it, even though I used 4wd everyday.

 

Got it. So now the LSD issue, I made the assumption all 4Runners came with LSD. Is this inaccurate? I badly need to get my rear diff completed and now im confused on which oil to use.

 

5th gen 4Runner’s do not have a limited slip rear differential. They are open diffs unless you have a Trail, TRD Off Road, or TRD Pro in which case you’ll have an electric rear locker. In either case, gear oil with the limited slip additive is not needed.

 

You can use LSD approved oil. It won't damage the open or locking diff.

Toyota dumped the the mechanical LSD across the board in the late 2000s for a brake actuated system.

 

Sounds good, im going to try the Amsoil since it comes in a squeeze bag and the price is not too bad.

 

Car Care Nut (Toyota/Lexus Dealer Mechanic) confirmed as long as you change @ 30K you should be good. He specifically mentioned the "Break-in" thing is not an issue.

https://youtu.be/0URaztDXHco

 

Car Care Nut also said you can use the same oil that the diffs use in the transfer case rather than the specific 75w. I believe that’s what the dealerships do.

I’m planning on changing my gearbox oils this spring. Planning on using regular gear oil rather than the higher priced synthetic.