Mixing 80w-90 and 75w-140 Diff Oil?

[SwampSurvivor]

I'm going to change the oil in my differentials before my wheeling trip next weekend.

I qualify under a "severe" use. I also have a bit of whining on deceleration.

Trying to avoid running something too heavy and burning it up. Would I be okay mixing 80w-90 and 75w140?

Yes, I know I should take care of the whining but I am saving up for a regear/bebuild anyway. The whining hasn't got worse since I bought it 20k miles ago.

 

[friendly_jacek]

How about SAE 110 oil instead?

 

[widman]

Why not stay with the 75W-140 that Jeep says? Better economy on startup and cold weather, better protection at high speed or load.
And probably calls for LSD as well, right?

 

[SwampSurvivor]

Originally Posted By: widman
Why not stay with the 75W-140 that Jeep says? Better economy on startup and cold weather, better protection at high speed or load.
And probably calls for LSD as well, right?


Would it be safe to run 75w-140? Service manual says 80w90 for Cherokees with the 8.25 rear end. however, Dodge Dakotas can take 75w-140.

No LSD, only open diff

Originally Posted By: friendly_jacek
How about SAE 110 oil instead?


Would that lubricate well enough?

 

[Loobed]

Look at Red Line's Shock Proof gear oils.

http://www.redlineoil.com/Products.aspx?pcid=8

 

[UNC151]

Originally Posted By: Loobed


Look at Red Line's Shock Proof gear oils.

http://www.redlineoil.com/Products.aspx?pcid=8



Or Amsoil's Severe Gear oil....

 

[SwampSurvivor]

I'd like to try to avoid the really expensive fluids. It's going to get rebuilt when I have it regeared so the expensive fluid would go to waste.

I should be okay to mix 75w140 and 80w90?

 

[UNC151]

Originally Posted By: Miller88
I'd like to try to avoid the really expensive fluids. It's going to get rebuilt when I have it regeared so the expensive fluid would go to waste.

I should be okay to mix 75w140 and 80w90?

Depending on how quickly you are going to rebuild, why even bother with synthetics (if that was your intent)? I would grab some Valvoline/Pennzoil/SuperTech/ and use that. Any decent conventional would get the job done and since you are rebuilding, I see no problem with mixing different viscosities...

 

[SwampSurvivor]

Apparently what I was looking at is 85w140 - not synthetic and about $12 a gallon. This would be safe to mix with the 80-90

I'm going to be doing this summer 2013. I don't put a ton of miles on the Jeep and it hasn't got worse in the 20k miles I have put on it thus far.