Since I have about a dozen 8.8 posis lying around I wondered if one would fit my 97 F150?
I've been wanting to do that for awhile, anyone done this before?

 

the center chunk should be the same as long as yours is a 8.8. but not positive

 

both 8.8's , so if the f150 has 28 spline as well its all good.

 

all the truck 8.8s have an extra wheel attached to run the speedometer.

if your truck is a 5.4 it should also have a 9.75 ring gear...

 

No the truck is a 4.6, but what's with the speedo-wheel? Does it unbolt and can it be exchanged with the posi unit?

 

it sort of looks like an ABS ring found on an axle but bigger. it presses on the differential. I not sure if the car 8.8 has the extra machined grove to press it on??

 

OK, but it's on the axle right?, all I'm going to do is swap in the posi unit.
Pop out the axles, pull out the old dif, exchange the ring gear and reset the backlash on the posi unit and put it all back together.

 

no. its on the differential, like this.....



IIRC its 31 splined also

 

HHhhhmmmmm..........................
That would throw a turd in the punchbowl