Does any body know what f-150 truck package just automaticly came with a posi rear end ?

Ford Rangers 4x4 STX package came with posi as standard eqt.
as far as i have been able to figure out.

I now own an 89 full size Bronco and want to put a posi rear end
in and do it cheap its just a winter beater for now. would appreciate any help.



THANKS ,
BOW TURKEY

 

My 1997 F-150 Lariat with the 5.4 V8 has a posi rear end. I have to add a friction modifier to the syn fluid. I have a tow package that came with.

 

"Trac-Lok" is the Ford term
Only GM people call it a "posi"