I have not bought yet but I am seriously looking at a 2013 F-150 STX "4wd" You will see why I put that in quotes in a moment 5.0 super cab with axle code 19 obviously that is a 3.55 open ratio. but I want to know without crawling under it does anyone know the specs to know if this is an 8.8" rear and 8.8" front?
I want to put limited slip on both front and rear. The 8.8" is easy to find, easy to pull they are a dime a dozen in the pull it your self yards. So, my question is 2 fold. I am 99.9999999% sure that front diff on those trucks is an 8.8" Will an LSD carrier out of an 8.8" rear say old explorer fit? Has anyone tried?
I know if my rear is an 8.8" its an easy swap. If the front is also an 8.8" are the carriers the same as the rear of the 8.8 explorers or would it be more like a ranger/mustang 28 spline but the same size?

 

I know my 14 xlt 4x4 and my 07 lariat 2wd were 9.75 rear ends

 

What axle code did yours have? I am curious if the 19 is an 8.8" 3.55 or a 3.55 any size.

 

I dont believe any 4x4's had the 8.8 in the rear. You most likely have a 9.75 rear.

I dont know if an 8.8" rear diff would work right. I know there was another thread where a guy was trying to put a torsen/trutrac in his front diff and eaton told him not to because they were meant for rear axle rotation. The front rotates the other way since its basically installed reverse of the rear axle(driveshaft comes in from behind the diff). At this point I think the best option for the front is to try and locate a Raptor front Torsen diff which is what that same guy ultimately ended up doing. Those are designed to works as a front diff.

As far as axle codes go, they only specify it in this document as an open 3.55 so I think it could be either size.

https://www.ford.com/resources/ford/...rv&tt_f150.pdf

 

axle code 19 is of course 3.55 ratio....& can be in either 8.8 or 9.75 rear axles... to be a posi-trac rear axle it would have to have a "H" suffix ahead of the 19 code. Eg: (H19)...I believe I'm right in also saying posi is available in both rear ends?

 

I knew the raptors had a Torsen front diff but they also have a 4.11 ratio. I KNOW with the old 8.8"s (again I am just going back to what I know) the ratio made a difference there was a 3.73 and lower (numbers) carrier which differed from the higher than 3.73 because of the number of bolts in the ring gear. THAT could be a big problem trying to take a raptor Torsen and put it in a 3.55 but not 100% sure. What you are saying though makes sense.

 

I see you found the other thread I was talking about, looks like he kept his 3.55's. I would love to do that mod, but just not sure I need it. I already have the rear e-locker.

 

 

9.75 is what I got.

 

Thanks for the info on setting the ring depth it makes a LOT of sense I thought it was because of number of bolts on the ring gear. I learned something. As for cost. You really can't beat $75.58 +$10 core plus rebuild kit vs new. Add to that the fact that LKQ where I will pull this has a TERRIBLE habbit (that works in my favor) of not draining or punching holes in diff covers. Sure I take a bath in stinky gear lube when I pull one but it stayed lubed usually. And I can get a good cover if I need one.
FACTOR INTO THAT. every Memorial and labor day weekend they have a 50% off sale You aren't going to beat $38 for a loaded chunk If the spiders are solid Why change? If the clutches are good I might not even change though I likely will.
First I need to jack this thing up and put it in neutral and test. I mean previous owner put a leveling kit and 34" Nittos on it. He MAY have invested in a limited slip rear for this truck who knows?