My mechanic used toyota t-iv transmission fluid in the rear differential. He said that is what the service manual says. Is he right? Are they compatible and is it safe to drive? Thanks.

 

amsoil synt fluid is the bomb, that´s what i use on my Kazz Lsd im sure it would great on a stock unit..

 

ATF in the Diff?? Never heard that before... I think T-IV is too thin for the diff. I believe you need to go with 85 or 90 weight hypoid diff oil.

 

ATF is too thin! Get that stuff out. Did you mean the transmission?? I hope you didn't pay for this service and you are asking before the job is done.

 

The differential is in the rear...of your car. lol. Use 75w90 weight GEAR OIL for that. Two bottles of Mobil 1 or amsoil.

The tranny, just use OEM TOYOTA iV trans fluid. Nothing else!!!

 

I did the rear diff change out two weeks ago....this is by far the worst job I've ever done. I think I will pay someone next time to do it because my freaking generic hand pump from advance auto didn't work as well as planned, didn't fit in the M1 bottle and kept spilling everywhere.

Next time, I might use the amsoil gear oil that has the pump that SCREWS onto the bottle. Probably is easier this way.

 

LOL i thought it was one of the easiest jobs to do. just time consuming pumping that.. pump.. not really used to pumping things jk.

and to the OP... GEAR OIL! T4 is WAYYYYYy to thin

 

your mechanic is incorrect. Lexus specifies 80W-90 gear oil (75W-90 can also be used) for the rear differential. This has never been changed. Always use gear oil in differentials for Toyota/Lexus vehicles. You'll want to get that out of there quickly. It doesn't have the correct viscosity, or the correct additives for the diff. The gear oil has EP (extreme pressure) additives that are required. This is why gear oil is so stinky. Lots of sulfur and anti-wear additives that are not present in automatic transmission fluid.

I don't know if there will be issues down the road with compatibility. Hum... I guess I would be inclined to do two changes of the diff fluid to get the auto trans fluid out of there. Change it once, drive it around the block, change it again. That should rid the diff of nearly all contaminants.

 

Thanks for all the responses. I'll need to get it out ASAP.

 

My pump didn't work so it was barely pumping anything to the diff. Then the oil was spilling over me...it took awhile to get the gear oil smell out of my pores lol.

 

our differential uses 75w oil not ATF