My son pulled the rear from his 86 F150, and installed it in his 94, but now the tyranny won't shift correctly. I'm assuming it's because it's not getting a signal from the tone ring/speed sensor. Can anyone tell me if you can retro fit a tone ring and sensor on an older 8.8?

 

I doubt it. You need a hole in the housing to mount the sensor. You are correct, that's messing up the tranny. Does he have a electronic speedo? If he does, it's not working right now either.

 

I'm pretty sure '92 was the split to PSOM.

1987 (like mine) -and up- have the sensor in the diff for RABS.

 

Yup, you need an 87 up axle.