Rear differential Oil ?

Couldn't find a relevant thread but I know my 01 4x4 with the locking rear diff calls for SAE 90 hypoid gear oil but I can't seem to find it. What should I put in it? Any help would be much appreciated!

 

Not sure what you mean, as gear oil XXw-90 is common...

if you're asking about the XXw part, owner's manual says 80w-90 but you can put

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

75w-90

 

No, my manual calls for sae 90 hypoid gear oil for the rear diff and 75-90 for the manual trans and transfer

 

ah, yeah, the "SAE 90" oil.... They usually have some at walmart, canadian tire and auto part stores.
SAE 90 would be 90w-90, but it does not exist...you can replace it with 80w-90, as it is what would be the closest

 

What is the GL spec called for? Thats important to get right.

 

I just did both diffs. Mobil 1 75W90, is what used on both diffs and the transfer case. Oh, and I have the E-locker!

 

04 e-locker here, I use Valvoline 75w90 in mine.

 

amsoil oil severe gear

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

75w-90 in diffs and t-case

 

Most standard oils give the additives in them to reduce the slip that hypoid bevel gears produce, lucas oil is a great lubricant that i personally use, but mobil, valvoline, Pennzoil, etc will be fine as well.

 

Just did my rear diff on my 2000 TRD with Mobil 1 75W90 synthetic gear oil. Truck has about 190,000 miles on it and I looked like it hadn't ever been changed. Super easy process to do, just remember to get a new crush washer for the fill and drain plugs.

 

I used RP 75w90 in front diff, transfer case and rear E locker diff. And no I never tow anything.

 

This has always concerned me too. You can use 80W-90, but it is only intended for temperatures less than 0 deg F. I went to the dealership to see if I could get some SAE 90 and the parts guy told me all they use is 80W-90. I have always used 80W-90 and haven't had any issues, at least not yet. 260,000 miles and counting... no issues.

I don't know if it makes a big difference, but this is always at the back of my mind when I change the rear diff oil.

 

I checked a tractor supply store and they carried straight SAE 90, but it was not for hypoid service. I wonder if there is an additive that can make it useable?

 

Why? Just go grab some Pennzoil from advance and change it every 30K or sooner depending on driving style. I promise, that rear diff will live for longer than the truck with shitty ass oil if you ain't driving it hard offroad and bouncing it.

 

My only real concern is, it gets over 100 F just about every day in the summer where I live. Otherwise, I probably wouldn't blink an eye. I also use cheap oil, usually SuperTech, or whatever is on sale at Walmart.

 

I use all Amsoil in my 2004 2.7 RC 4X4. 75-110 severe gear in front and rear diffs and Amsoil GL 4 in the trannny. MMMMM. I forget what I put in the transfer case but it was what Amsoil recommends. Probably 75-90.

 

Diff's get warm regardless. If you use shitty oil change it sooner. If you offroad a lot and use shitty oil then change it even sooner. Theres a balance and money can be saved by using cheaper oil, just be weary of your driving style, running through water, hard on the gas, etc. If you put your hand on the rear diff and it burns the hell out of you, probably would be best to use better oil! I just try for the cheapest most common sense stuff for me and my terrain. Everyone will be different.

 

I use Valvoline for all fluids....

 

Use a 100+ weight then, like 85-140. Hell, ECGS insists to use 85-140 dyno in their diffs: http://eastcoastgearsupply.com/ft-2536-ecgs-gear-oil-recommendation.html

Also: useful video.. explains oil weights and the XXw-XX oils.
https://youtu.be/tYkg0oDUXs8

 

Hypoid beveled gears don't slip. The additive is for positrack type differentials with clutch packs. Our e-lockers are mechanically engaged by a sliding splined collar. Additive is not required.

I run Mobil1 75-90 synthetic in my elocker.