Question about Gear Oil.

[midtnranger]

I am changing the oil out my front and rear diff, I bought some Valvoline 80w-90 synthetic today, will this be ok for my Dana 35, and 8.8ls?

 

[ThatGuy]

I don't know if the rear requires a l/s additive or not but it will be perfectly fine for the front.

 

[superds]

This question is almost like asking about religion or politics. There can be much debate on it.

If you read your owner's manual, that will tell you the factory recommended lubes to use. It probably specifies 80w90 for the front and 75w140 synthetic for the rear with 4oz friction modifier.

I personally recommend synthetic for virtually everything anyway, so I think you're good with that for the front. Some might say that your selection for the rear is too low in viscosity but I know some people have run lighter than recommended axle lube with good success (in the effort to increase gas mileage, and without destroying the axle). Based on their experiences, you should also be ok with that lube in the rear.

 

[midtnranger]

The Valvoline I got says it is for limited slip, I'll use it up front, and get some Mobil One LS 75w 140 for the rear. I did not get a manual with mine, I was just going by the Haynes manual. Thanks for the help.

 

[superds]

The Valvoline I got says it is for limited slip, I'll use it up front, and get some Mobil One LS 75w 140 for the rear. I did not get a manual with mine, I was just going by the Haynes manual. Thanks for the help.

I personally would just run what you already bought. I think you will be alright.

 

[superds]

If you want a pdf of the owner's manual you can look here:
https://www.fleet.ford.com/maintenance/owners_manuals/default.asp

It only goes back to '96 but a lot of the information will be the same as your '93.

 

[4x4junkie]

I'd put whatever in depending on your climate.

If you have real hot summers where you are, use like an 85W-140.
If you have really cold winters, use 75W-90.
If you have both, then a synthetic 75W-140 is probably best.

 

[superds]

Interestingly, I searched for several different years on the fleet.ford page that I posted and it looks like for the Ranger axles it generally recommended dino 80w90 (until the FX4 model was introduced) and for the Explorer with L/S it recommended the 75w140 like I had first mentioned.

 

[midtnranger]

If you want a pdf of the owner's manual you can look here:
https://www.fleet.ford.com/maintenance/owners_manuals/default.asp

It only goes back to '96 but a lot of the information will be the same as your '93.

Thanks.