I am planning on changing the rear differential fluid, I have a 1992 Ford F150, how can I tell what kind of rear end I have? When the wheels "spin out" only the right side or passenger side rear wheel spins while the drivers side stays stationary if that makes a difference. I just need to know 1. How much fluid will I need approximately, and 2. Will I need a friction modifier or not? Thanks in advance!

 

One thing I forgot was the weight of the gear oil! I will need to know that to!

 

Look at your door sticker and you'll see an axle code. Google ford pickup axle codes and you'll find it. Several different axles under these trucks. Probably going to be a non limited slip and will use regular 80w90 gear oil.

 

Thanks unit! I looked it up and its code "19" for a regular rear end with 3.55 gears! I just need to know how much fluid it will hold? Thanks!

 

Seems like I put a bottle and a half of the 80w90 the last change. I don't think one bottle did it. Just fill it until it runs out of the fill plug and let it stop dripping out and replace the plug.

 

Alright thanks for the help !

 

I have a code 19 rear end and I use synthetic 75w-90 rear end gear oil.

 

Synthetic is good too. I'll be swapping to synthetic at the next change.

 

I'm almost due for my next diff fluid change and going to put synthetic in it. Rear diff holds 5.5pts of gear oil which is about fill plug level.

 

Thanks for the help guys, I think I am going to go ahead and put the synthetic in and change the fluid when I have some time. I'm looking forward to how it drives after the fluid change!