Hello,


I am reworking the front axle of an old F-150. It is an 86 with a dana 44 IFS in the front. I lost an axle ... upon inspection all three axle u-joints were gone and two axles needed replacing. Since I had to pull the pumpkin to get the c-clip, I decided to rebuild the entire axle ( bearings, seals, ....). The truck is not much to look at ... rusty and 250K miles .... but it runs well.... and best of all, it only cost me $1000 including a plow!



I live in Vermont. The truck is driven daily but the front axle is really only used when plowing ( just my own private driveway ... 2 hours a couple times a week max). Temperatures here do reach -30 deg F. We had three days over 90 here last summer. I used the truck in 4x4 mode twice just to pull the lawn tractor out of the mud ( stuck in a ditch ).


After 4 days work to set the gears up ( my first time doing this ), I got it right.


Now it is time for oil.


HELP !!!!!



My Ford manual does not say what weight oil to use.


I found an older manual on line. It says 90 SAE or 80W-90 ..... 80 if used below 0 deg F.



I use synthetic oil in all my vehicles (engine, transmission, diff, grease, everything).

I did a quick search ... 80 synthetic is almost none existent.


I did find 80W-90 locally but not in synthetic. It looks like I can order this in synthetic ... Royal Purple or Amsoil

I found 75W-90 synthetic available at several local suppliers. Lots of choices ... Mobil 1, Lucas, Valvoline, Royal Purple ...



I called Dana/Spicer tech help. They said it came from the factory with SAE 90 and that was all they could recommend.


So my question, if I want to use synthetic, can I use 75W-90 or do I need to order 80W-90 or ?????


Thanks .... Mike

 

I'm running royal purple 75/90 in mine. Dana won't tell you different because that's a liability on their part.

 

75-90 synthetic gear oil is fine.

 

75w90 synthetic for 9 years now