Old truck rear end oil which one

old · Aug 4, 2017

So son is changing his rear end oil . He got the 80W-90 and I told him I would use the newer 85W-140 what would you use. 1991 Toyota 4X4 pick up by the way. I my self use the 85W-140 in my 1980 Chev front end and rear end

4520BW · Aug 4, 2017

I am thinking 80w-90 was for standard diffs and 85w-140 was for locker rear ends. Don't for get limited slip additive if needed.

mj · Aug 4, 2017

(quoted from post at 16:16:14 08/04/17) So son is changing his rear end oil . He got the 80W-90 and I told him I would use the newer 85W-140 what would you use. 1991 Toyota 4X4 pick up by the way. I my self use the 85W-140 in my 1980 Chev front end and rear end

Toyota probably calls for GL90 but on my older stuff I use 80-90. The 80W-90 should be fine.

Janicholson · Aug 4, 2017

In Missouri the heavier oil is not going to stiffen up anything. If it is a posi look at the tech spec to see if it needs additive. Jim

tomNE · Aug 4, 2017

either one works; especially if light duty!

JDEM · Aug 4, 2017

Toyota calls for a GL5 gear-oil with a viscosity that matches the temps it is used in. Makes no difference with either oil assuming they are both GL5. The Toyota manuals trans however, calls for GL4 (made by Aisin).

guido · Aug 4, 2017

Hello old,

85w90,

Guido.

banjoman09 · Aug 4, 2017

Either go with the manufacturer specs, or 85w-140. We usually ran the spec oil til "out of warranty" then switched to 85w-140

Geo-TH,In · Aug 5, 2017

Old,
I'm cheap but I do maintain my toys and what the manual recommends on my new toys.

I change all oils on my kaw 4010 every 100 hours.
The front and real axles use 80-90w limited slip gear oil. That oil appears to have fine metal particles in it. If I put used oil in a plastic bottle and allow it to sit on shelf for a few months, the oil on the top looks like brand new oil, metal particles are on the bottom.

I put the used oil in the rear ends of my old tractors. Can't see what it really hurts. Keep in mind, the 80 is the cold temp weight of the oil. 80-90 vs 80-140 is suppose to be the same oil, 80, at cold temps. The 90 and 140 is the weight at some higher temp. Just how hot does the rear end get?
geo

MarkB_MI · Aug 5, 2017

There's no reason to use the heavier oil in a light-duty truck. All it will do is cut down on gas mileage in the winter. Also, thicker oil is going to have a harder time getting out to the wheel bearings.

A more important consideration is whether or not it has a limited-slip differential.

old · Aug 5, 2017

Ah but I do not live way up north like you do so the heavier oil is just fine year round since it is still 80W when cold but heavier when hot out and common to see 100 degree days here plus the boy drives his truck like it is a WW2 Tank

old · Aug 5, 2017

Reason I told him to use the heavier duty oil is because he tends to drive thing like there army tanks or in other words he is hard on stuff

docmirror · Aug 5, 2017

The difference between the two weights is the amount of viscosity modifiers added. These are long chain polymers which change shape with changes in temperature. If the 85W-140 is GL-5 rated, then it's ok to use it.

As for the friction modifiers for limited slip, they should only be used in trans or diff where specified.

Geo-TH,In · Aug 5, 2017

If you already decided what you are using, Why the post?

old · Aug 5, 2017

More or less to find out which in the long run would be better

Old truck rear end oil which one

old

Well-known Member

4520BW

Well-known Member

mj

Well-known Member

Janicholson

Well-known Member

tomNE

Member

JDEM

Well-known Member

guido

Well-known Member

banjoman09

Well-known Member

Geo-TH,In

Well-known Member

MarkB_MI

Well-known Member

old

Well-known Member

old

Well-known Member

docmirror

Well-known Member

Geo-TH,In

Well-known Member

old

Well-known Member

Similar threads