Running 75w140 in the rear diff a bad idea?

[jman11788]

I will be installing a new diff this week with 4.88s and an e locker. I keep seeing and hearing of people with diff failures. My 4.88 just failed with 75w90 Lucas hd fluid after 2 months. I really can't afford to have this happen again. Wondering if the heavier duty fluid will help with wear on the bearings. I know the redline and amsoil stuff is good. Should I just try that? I don't mind suffering mpg if it's helps with wear.

 

[theesotericone]

2 months? Did you break the diff in properly? If not make sure to follow these guidelines for the new diff. There's a lot of info about breaking in gear sets out there if you look for it.

New Gear Break-In Procedure

 

[Tyler James Inc]

There is no way the "wrong" diff oil would cause a properly set-up diff to fail. What failed? Are you having the same shop set the new diff up?

 

[jman11788]

This diff wasn't new. It was used with 130k on the gears and everything. I installed it

 

[SIN-Japan]

ECGS recommends Lucas Non-Syn 85w-140 for Gears and Lockers.
I have been running that for almost 2 years with no issues.

If you were running a used diff with that many miles on it I do not think the issue was the diff oil.

 

[19963.4lsr5]

I put 75-140 in the puppy hauler cause that's what I had on the shelf. Your good.


Sent from my iPhone using Tapatalk

 

[jgue467]

I've run wallyworlds full synth 75-140 for over 100k miles, zero issues. It's not as thick as it would seem so go for it. :cowboy:

 

[alumarine]

Why not use what Toyota recommends?
Seems to work for millions of trucks.

Something else might work, but it won't work "better".

 

[jman11788]

Why not use what Toyota recommends?
Seems to work for millions of trucks.

Something else might work, but it won't work "better".

Probably because it'll be $100 for 3 quarts lol

 

[T4R2014]

I'm using it to cover up a bad pinion bearing as best as I can until I swap it out.

 

[alumarine]

Probably because it'll be $100 for 3 quarts lol

What are you talking about?
They only recommend a weight, not a brand.
lol...

 

[alumarine]

I'm using it to cover up a bad pinion bearing as best as I can until I swap it out.

Now that's a good reason actually.

 

[jman11788]

What are you talking about?

They only recommend a weight, not a brand.

lol...

I thought you were referring to running Toyota fluid. My bad


Sent from my iPhone using Tapatalk

 

[alumarine]

I thought you were referring to running Toyota fluid. My bad

You're right though, Toyota gear oil would be expensive!