I found the rearend I need, its a 7.5 4.10 gears with a locker. The yard where I bought it for some reason pulled the cover to look inside, thus draining the oil. I have read somewhere that you need an additive in the oil which I think that you have to get from Ford. Can any of you helpful members steer me the right direction? I need to put this in tomorrow. Also this one may have the 10 inch brakes. If it does do I have to do anything additional to my brake system? Thanks for all your help and responses.

Randy

Ford Friction Modifier...

Don't know if it's used for lockers, but that's what my friend put in the rear end of his '90 Mustang GT after he redid his clutch pack in his posi unit.

And I think the 7.5's have 9" drums, the 8.8" rears have the 10"

Traction-Lok needs friction modifier if you use "Dino" oil. For synthetic lube, nothing else is needed. Amsoil, redline, etc make good 75-90W for just that!

How about valvoline semi-synthetic. It's all I can find except dino oil here.

so if you have 7.5" you have the 9" brakes and 8.8" you have the 10" not interchangeable?....

Ooo... :ooer: Tough one.
The 9" brakes (9"x1.5") are 7.5" rear, standard cab only. The extended cabs and 4x4's have 10" drums (10"x2.5"!!). This is decided by gross vehicle weight.
If you want 10" brakes, go to your local junk yard (or e-mail me, I have a spare set of backing plates $40 + shipping) and get the rear brakes off an Aerostar. Perfect swap with the Ranger. I got the whole system (for cores) for $60, bad drum, burnt pads and all.

I don't know about the 8.8 10", but I'm pretty sure the backing plates won't work. Drums and shoes are the same though...

Originally posted by BOSS 3.0
The 9" brakes (9"x1.5") are 7.5" rear, standard cab only.


My standard cab with the 7.5" rear has the 10s... ;) ...But, thats cos I got the heavy-duty payload package #2 dealy...Mainly for the bigger sway bar... :E

So to be safe I used Mobil 1 AND the friction modifer. I hope they are compatible.

boss.

i am sure they are the 10" ones. i have the 4x4 and girlfriend works at a brake pad manufacture so she looked up the pads. 10 x 2.5 i am trying to find out if its a 8.8 in the rear end. code on door is 86 so i know it is open differential. by the way the shoes do make a difference. the size of them. and i beleive the drum is also bigger. but this info comes from my gf.

luis