98 F150 8.8 or 9.75?
 

I've got a 98 Extended Cab 4x4 w/the glorious "Off Road Package". Now I would've thought that with this pacakge Ford would've included the limited slip rear end considering that open end is worthless "Off Road", but of course they did not. So I'm stuck with the 3.73 non limited slip.

I've got a 31 spline 8.8" rear end out of my old Lightning sitting in my garage and I want to know if it'll fit into my current truck without too much hassle. It needs a clutch rebuild and new spiders, but the housing itself is good. I replaced it with an Eaton in my old truck, but for this one I don't really see the need to drop that kind of coin unless I'm doing extensive off roading, which I'm not. I just want a little better traction in the snow and wet conditions.

So does anyone know why my pile has in it? Was there some sort of option for the larger rear end or was it includng possibly with a towing package? Or am I just retarded?:D

Do you have an F-150 or an F-250 LD? If you have 3.73:1 gears it is most likely that you have an F-250 LD. If that is the case then you have a 10.25 inch ring gear. If you have an F-150 with a 5.4 then you have a 9.75 inch ring gear and if you have a 4.2 or 4.6 then you have an 8.8 inch ring gear. One more thing is the fact that you mentionned that you have an old Lightning. Is it a GEN I Lightning? If it is, most likely because you write that it has an 8.8, then you are out of luck. The 97+ 8.8 inch differentials are not interchangable with the earlier versions. I suspect the reason is the anti lock speed sensor ring for the ABS or lack there of.

Regards

Jean Marc Chartier

Yeah, I did a little more research after I posted this and figured out that I do in fact have an 8.8, but as you said - it isn't interchangeable with my old Gen 1 8.8 rear end.

That sucks but oh well.

/me continues doing one wheel burnouts in the rain.