[Drcoffee]

I see a few threads around the web on 75W90 vs 75W140, Dino vs Synthetic. What is everyone using in the rear axle? Mine started leaking when I put in Mobil1 75W90 but that was with older seals and I kind of expected that to happen, but hoped it wouldn't. With the new seals in now, I'm thinking about draining the M1 out and going to Royal Purple 75W140. So I'm curious what others are using and what kind of results you've had.

* Maybe just list what you drianed out and what you refilled with. This could be a good thread for others to weigh their choices before a fluid change.

[Steve240]

I put in conventional 75/90 as I read somewhere that the seals were not designed well to hangle the smaller molecules of synthetic. I also read that by replacing your seals are upgrading to the new design which can handle it. Either way I stuck with conventional as my truck is pretty much stock and I don't wheel yet but I am interested to know what people with modified rigs are running.

Do our diffs need GL 4 specific? What about the locking diffs? I know with some older vehilces the GL 5 fluids can eat trans synchros any issues with the 4runner??

[Mf Baker]

I used Kaaz performance LSD 80w90, straight from japan ;)

[Mano1124]

I put in Mobil 1 Synthetic after replacing the rear axle seals and so far no leaks.

[madbomber08]

I used redline synthetic throughout because i have a 5 spd. I believe it is a 75W-90 for the diffs if i remember correctly. No problems.

[Loyal Toyota]

I use Mobil 1 75W-90 LS in the front, transfer case, and rear differential with no problems at all. Change at 30k intervals.

[Bennythbeaver]

I just switched over to Aimsoil severe 75-90W. Great stuff! I paid $15 a quart at my local auto parts store. I put it in the front diff, transfer case, and rear diff.

[02SE]

I've been using Mobil 1 75w90 in the rear axle, front diff, transfer case, and the manual trans, since I did the first change at 3000 miles. I've changed it a few times since then, too.

14 1/2 years later, it's still fine.

I ran the Mobil 1 75w90 in the trans for the first 13 years, but I switched the gear oil I used in that to Redline MT-90, a year and a half ago. There were no real changes in shift quality, it still shifts fine.