What gear oil weight should I use???

[ftlbs]

What gear oil weight would you suggest I use in my 1973 Bronco with a Dana 44 and a Ford 9"?
I live in Utah where it gets near the 100 degrees in July and close to 0 degrees in the winter. Any suggestions would be appreciated.

 

[stock1970]

If you have limited slip make sure you get the oil that is designed for that. The gear oil should be at any automotive parts store and will be clearly labeled.. It has been awhile but I got mine at autozone.

 

[ftlbs]

If you have limited slip make sure you get the oil that is designed for that.

I do have limited slip in the rear and I have an additive that I will be adding to the oil. I just don't know what oil to buy. Should I get 75W-90, 80W-90, 85W-90, 75W-140, or what?

 

[stock1970]

I checked my left overs and i went 85w-90.. in kansas it gets hot and cold.

 

[broncnaz]

What ever you can get is fine I've run 80-90W most of my broncos life including a few years in northern utah with no problems. Although the 75-140 is a good choice give the best of both worlds.

 

[Broncobowsher]

75W90 should be fine unless you are trying to tow in the summer. The 140 part is only worth it if you do high loads for long runs and need to worry about heat.

These axles are dinasours. they will run on about anything. Keep something that resembles gear oil in them and they will live nearly forever. They are not picky about what is in them. What ever gear oil you already own is going to be perfect as well.

 

[Heus33]

Might want to try Amsoil. 75W 90 Part number SVGQT-EA

I've had good luck with it in my Xterra.

 

[ftlbs]

Let me ask this...are there any reasons to NOT use 75W-140 over a typical 75W-90, 80W-90, or something similar? (are there any "cons" to using 75W-140?)

Front Axle: Dana 44, 4.10 gears, Open
Rear Axle: Ford 9", 4.10 gears, Limited Slip (I will add a L/S additive)

 

[Heus33]

Let me ask this...are there any reasons to NOT use 75W-140 over a typical 75W-90, 80W-90, or something similar? (are there any "cons" to using 75W-140?)

Front Axle: Dana 44, 4.10 gears, Open
Rear Axle: Ford 9", 4.10 gears, Limited Slip (I will add a L/S additive)

Is there a reason you'd want to run something that thick? I'm no expert but usually 140W gear oil is used in racing applications.

 

[Ohio Bill]

75W140 is what is used in semi's......I'd say way to heavy for our trucks. I would use a 75W90.

 

[Broncobowsher]

If you have 75W140 on hand, use it.
Being thicker it can rob you of power and economy (very little)

A lot of newer trucks now spec a synthetic 75W140 in order to get better towing performance out of a truck that is reeally too light to really do the job. Instead of using a larger axle that can take the power they keep an undersized one and use synthetic 75W140 to try and keep it alive when it gets hot.