I got a 97 f150 4x4 4.6 I plan on changing the rear diff fluid what should I use when changing it what kind of fluid and any additives I live in ma so the weather changes a lot

 

9.75? 8.8? LS? FX4? Come on dude we're not mind readers. Do use all a favor a read the tag on the rear diff and hit the google machine. If it's a LS diff you'll need a bottle of friction modifier from ford. 5$ and stinks worse than the diff fluid. Even if the bottle says friction modifier added still put the FM bottle in.

 

I think it's the 8.8 not entirely sure how to tell

 

Count the bolts, 12 is a 9.75

 

It's got 10 bolts

 

Then it's 8.8

 

What kind of fluid should I use do I need a friction modifier

 

Between 2.5-3qts of 75-140 diff fluid and a bottle of friction modifier. You should be able to stick your pinky in the flill plug on the front and just be able to touch fluid on level ground. Check the tag on the diff and make sure it's 75-140

 

Maybe someone should have read the OP. You dont have to be a mind reader to know that a 4.6 powered truck has a 8.8..

 

Just look in door jam.

The axle code is there and just cross reference it with the "FAQ" sticky post on this section.

I have an H9...

3.55 LS 8.8