I was going to change the rear diff fluid on my dad's 06 F150 today, but wasn't sure what rear end was in it. I checked the manual and it gave fluid capacities for the 8.8/9.8 rear end which holds 5.5 pints, then there was the sterling 10.25 that holds 6.9 pints. I've changed diff fluid before and know you can just fill it until is seeps out the fill hole, but I just wanted to double check and find out what rear end he has. It's an 06 F150 5.4 2wd 3.73 LS. Any help would greatly be appreciated.

 

pretty sure the sterling is for f250+

 

There should be a couple tags under the bolts on the rear diff cover. Those have the info you are looking for as far as which rear end it is. ie 975 would be the 9 and 3/4 etc.

 

Also, don't forget the additive for the LS

 

Yea, I changed the fluid in my F350 and used the fluid with the friction modifer already in it. I like that stuff better. Ive used valvoline and mobile 1 before.