I was wondering if anyone could help me identify which of the lock right differentials would fit my truck. I have a 2010 f150 stx with the 3.55 non ls. If anything an id on the rear end would be very helpful. Thank you

 

i think if there are 10 bolts holding the rear cover on, it's the 8.8"...12 bolts is the 9.75". I had a Lock-Right in my old 90 F250 in the front diff..the front end dug too much compared to the rear with limited slip.