80w-90 vs 85w-140

[Chris142]

The guy that's rebuilding the rear axle in my Jeep wants me to use 85w-140 in it. Jeep says 80w-90 for normal use and 85w -140 for towing.

I don't tow anything with it.

He is pretty adamant about it too.

I don't think I need 85w-140 plus I have lots of Amsoil 80w -90 I want to use.

 

[c502cid]

It's your axle. Let him fill it with 140 from the start and change it after you break it in, maybe after 500 miles or so.

 

[Lubener]

It can be filled with either and won't make a difference. I would fill it with what your builder wants. You can always put in what you want later.This way he can't use that as a reason if the differential fails during his warranty period, if he has one.

 

[Jetronic]

The guy that's rebuilding the rear axle in my Jeep wants me to use 85w-140 in it. Jeep says 80w-90 for normal use and 85w -140 for towing.

I don't tow anything with it.

He is pretty adamant about it too.

I don't think I need 85w-140 plus I have lots of Amsoil 80w -90 I want to use.

why did it need rebuilding?

 

[ka9mnx]

why did it need rebuilding?

Agree. Why the rebuild? I think the mechanic knows what it needs. I use 75w-140 in all my vehicles since the SAE made 75w-90 a lighter grade years ago and Ford moved to 75w-140.

 

[Kira]

Go with the 140 as Lubener says.
Keep accurate fuel mileage records for a year or two.
Change to your 80-90 and continue to keep track.
You'll make BITOG history if you see any improvement in mileage.

 

[Chris142]

why did it need rebuilding?

Bearings wore out after 188000 miles.

 

[Jetronic]

those could use a bit more viscosity, the rpm is very low and the temperatures high. I'm sure that's why he wants 85W-140 in it. Towing makes both conditions even worse of course.

But are you going to keep it another 180k miles?

 

[Chris142]

But are you going to keep it another 180k miles?

I can't afford to replace it. Especially at the todays prices. I plan on driving it into the ground or untill it gets destroyed by another driver. I really enjoy driving it.

 

[wpod]

85-140 is much thicker than a 90 wt. Thicker oil protects better from shock loading. Unless you see below freezing temps use the thicker oil off roading. Using the Amsoil will give you the same life as the old unit or more if changed as needed.

 

[wpod]

The guy that's rebuilding the rear axle in my Jeep wants me to use 85w-140 in it. Jeep says 80w-90 for normal use and 85w -140 for towing.

I don't tow anything with it.

He is pretty adamant about it too.

I don't think I need 85w-140 plus I have lots of Amsoil 80w -90 I want to use.

You bring in you rear end to a guy you hopefully trust to rebuild the rear end then you question his oil choice???

 

[Propflux01]

You bring in you rear end to a guy you hopefully trust to rebuild the rear end then you question his oil choice???

People buy cars from manufacturers they trust and also question the oil choice.... Its why we are all here..

 

[Jetronic]

I can't afford to replace it. Especially at the todays prices. I plan on driving it into the ground or untill it gets destroyed by another driver. I really enjoy driving it.

There's a decent chance you wouldn't have had to replace those bearings with some thicker oil in it. There really shouldn't be much metal contact if the viscosity is aequate. But since rpm is 0 just before you start, there always will be some contact obviously.

For my own car I did the calcs for wheel bearings, and 75W-140 is the lowest I should consider (slow driving after getting bearings hot, so low viscosity low rpm). I have ball bearings though, they can do with less viscosity.

 

[dnewton3]

It's your axle. Let him fill it with 140 from the start and change it after you break it in, maybe after 500 miles or so.

This.

 

[zrxkawboy]

I’m sure either would be fine. Nothing wrong with the heavier oil in your climate.

 

[ollie]

I can't afford to replace it. Especially at the todays prices. I plan on driving it into the ground or untill it gets destroyed by another driver. I really enjoy driving it.

Plus that's a good year for the Wranglers. I think you should use up what you got. I doubt a heavier gear oil will make much difference.

 

[RDMgr]

I'm sure either viscosity would be fine but the big question is what the rebuilder requires to maintain his warranty. If you don't follow his warranty requirements he probably will not back his work if you have a problem.

 

[jeepman3071]

Which axle is it? D44 or D35?

 

[Dave9]

Doesn't get cold there (AV, CA), run the 140, probably wouldn't have had to rebuild (yet) if it had it in the first place.

 

[ripcord]

Did that unit leak? Running low on lube would be my guess as to why the bearing failed. Early 2000s Jeeps had problems with leaking axle seals in my experience.