Transfer case oil

I'm coming up on 30,000 miles soon. I planed to do my transfer case with MT-LV. That's what ordered from Amazon.
Not sure what I'm putting in the diffs yet. Probably going to use 75w90 synthetic, ether Mobil 1 or Super tech. I see Super tech is 10.45 a quart or I can order 6 quarts of the Mobil1 from Wal-Mart for like $63.

 

It’s just a transfer case….there is nothing to risk. You could throw ATF in it and it wouldn’t care. Toyota has a bunch of additives because it is super thin. I want to say the aftermarket stuff ran a tiny bit thicker and probably as such doesn’t need so many additives.

 

I used Amsoil severe gear for my diffs

 

I am by no means a professional, but everything I read states that gl5 should not be used in the t case due to brass synchros, which is why I even care to verify that

 

There is one synchro (to get the front driveshaft up to speed on the 2H to 4H shift). Ideally you use GL4 over GL5 because yes, GL5 has some additives that attack synchros. However, that happens much more significantly under load which the transfer case doesn’t really see. Also many modern GL5s have sulfur additives that are considered “inactive” and not actively damaging the synchro. So it’s not really an issue. Though I did personally choose GL4 anyways for mine. And the Toyota LF is likely just a very thin GL4 but I don’t know that for sure.

 

Amsoil is fine but you can't really convince me that it's a lot better than other synthetic oils that it's worth the extra cost. The other thing is I don't know if this is still true but you used to have to buy Amsoil from a distributor and when you talked to one you find out the company is a pyramid scheme and they try to bring you in to that.

 

Redline GL4 here for the TCase and MT. Different weights. MT LV and MT90 iirc.

I didn’t want to deal with the can and high price of OEM fluid. Unless I see a VOA of why it’s superior the redline is fine by me. It is after all a premium fluid to begin with.

also buying on Amazon with no hassle was important to me.

for the diffs I just used Valvoline 75-90 GL5.

Can’t say I feel a difference. Just happy to DYI and have fresh fluid and not have paid a grip to get it done. I did this change at 20k. Will probably do again at 40k then leave it all in there until 100k. Some folks never change these at all.

 

Send it, no harm in lsd additive when it's not needed

You could technically throw atf in there. The vehicles that spec it for a transfer case though such as GM don't use a manual transmission style syncro ring. They use a small clutch pack like you would find inside an automatic or a motor/dirt bike clutch

 

Jeep transfer cases use ATF and have a synchro on the 2018+ that have the front axle disconnect and the 84-95 that have the central axle disconnect. 97-18, no synchro because the front diff spun all the time. ATF in those as well. ATF with a synchro is not that weird, it’s no different than the Ford manuals having synchros but calling for ATF.

Almost every manufacturer calls for ATF in the transfer case…Toyota and the 70’s & 80’s Jeeps are all I’ve seen that don’t call for it. To be clear, I am not recommending ATF at all, I am simply trying to emphasize that this decision really should not be so difficult as transfer cases are not picky as to what’s in them. I am not recommending a specific choice either way. I don’t like when folks think the transfer case “requires” the Toyota stuff specifically.

 

Agree, if it was a full time transfer case I'd be more concerned, but its just a spinning device that is under minimal load 95% of its life. As long as it has lube its fine.

I change my tcase oil half as often as my diffs. And drive in 4x4 a lot more than most. Beit winter or fast gravel roads.

But I get that some want OEM spec for their vehicles.

 

Yeah, I don’t change mine often. And I agree, it is under almost no load, especially on the components. Almost all the load is on the shafts only, other than 4L. Everything else just needs lube to run smooth. And it’s all pumped so whatever you use as long as it’s liquid will reach everything.

No issues with folks wanting OEM either, I just think it’s overpriced and doesn’t provide anything special in the application of the transfer case, so I like to consider all the options.

 

makes sense. Manual trans is constantly being shifted and under load.

FWIW, under the Amsoil dropdown of tcase compatible fluid they list like 4. And only one is a thinner GL4 I believe. The rest have LSD additive. Which I’ve read is fine.
I may have accidentally put some in my tcase grabbing whatever gear oil I had and just got paranoid about it for a second. But it’s probably fine.

biggest thing I need to address is the trans breather (manual). It’s not that high up and the factory valve is clogged. Need to figure out which one is the right barb size and possibly two way metal cap instead of one way.
It seems harder to get to than the rest
Last full tcase fluid change was maybe a year or two ago so it’s probably got at least another year before it would be recommended to change again.

I’m guessing OEM fluid is more expensive and straight 75w for fuel economy and regular road use.

might pick a different brand next time like Motul or something. To see if it feels any different. But it’ll probably just work and feel the same.

 

@TacoTuesday1 - Please do post part #s, barb sizes, needed materials, etc. on the MT trans breather (if not a documented DIY process )
I did not know that the MT warranted a breather raise...
Not that I am planning on fording much water. I tend to drive around anything deep, I avoid mud, and we are not close to flood waters (biblical or otherwise).
I did do the Rear Diff... just in case because it is easy, I suppose.

 

so I did the common rear diff mod
Checked under the hood by the battery and there’s a holder with a bunch of breathers. That’s probably most of them like front diff and what not.

but when pulling the manual out to do a clutch, noticed the breather for it simply routes along the trans and mounts basically where the top bellhousing bolt is. Not really high up or relocated like the rest of them. Definitely lower than the rear diff extension.

I’ve seen variations in breather. Both barb thickness and one or two way. Dealer has different ones.
I think Amazon sells cheap Dorman too.

might be able to just take off the old one and measure with a caliper the diameters when I get to it.

I’m guessing two way valve may be better than one way.
Because if it’s one way to vent outwards from heat, then that doesn’t let vacuum escape. Which would then suck water through the seals.

rest of the easier to access valves I’ve already switched to two way.

 

ATF may be incompatible with the seals and cause leaks though. An input shaft seal leak or actuator leak would be onerous, requiring pulling the T-case.

Toyota had specified GL5 for the transfer case for more than two decades before the 3rd gen changed to the lower-viscosity fluid. Regular 75W90 GL5 isn't recommended for your T-case because of the viscosity - you may have difficulty shifting in colder temps, not because of the GL5/GL4 rating.

 

this makes sense. My regular DOT4 doesn’t feel as good cold.

and on a snowy morning I’d be in 4x4. If I know it’s gonna snow the next morning and is already snowing then I leave/put it in 4x4 first overnight so it’s already engaged.

I wonder what the 75w costs from the dealer and if anyone else makes a good and well priced equivalent that’s also 75w, not higher

$75 and a peanut can, yikes

 

Red Line MT-LV 75W openly declares compatibility with Toyota 08885-81080: https://www.redlineoil.com/mt-lv-70w75w#oem-compatibility-tab

Costs only $23: https://www.jegs.com/i/Red-Line-Oil/816/50604/10002/-1

The Red Line oil's price is lower than the discount off MSRP on the Toyota oil.

 

Maybe, though I’d be surprised if rubber seals in Toyota cases are really any different than any in other brands. Again, not suggesting ATF at all, just trying to make the point that they are really not all that picky about what’s in them. Especially about 3 different 75W gear oils that are more similar than they are different.

 

it wasn’t much more than anything else. I think it was 17-18 a quart and I ordered right off their website. It’s easier to get than it use to be.

 

I ordered the Toyota OEM fluid off of Amazon. Mine came in a plastic bottle. No more cans maybe?