I have a 97 f150 2 wheel drive, and I swaped the 9.75 axle from an 02 4x4 to gain the bigger axle and disk brakes. Now when I push my drive shaft in all the way I can get the drive shaft and the pinion (i think it is) to touch eachother. The broblem is that the bolt that holds the pinion in is sticking out too far for me to get it all the way over. I can move the axle enough to make it fit but would It be too tight of a fit if i did this? Thanks.

 

is it possible to get the drive shaft off the truck you got the diff from? I'd say you need a driveshaft from a truck with the 9 3/4 diff that has the same wheelbase or just have a drivleine shop shorten yours.
either way that drive shaft is not going to work the way it is, thats too tight of a fit.

 

the driveshaft is 1'' too long, relevant to the new, larger axle that's the problem. the driveshaft should be bolted directly onto the pinion flange, and should be sticking out 1 1/4'' out of the transmission tailhousing.

 

Yes, driveshaft is too long. If you force it in there, it will tear up the transmission tailshaft.

If that flange will bolt to the rear properly and the driveshaft is steel, you can have it shortened at a 4x4 place or a driveshaft place. I don't remember how much it cost me to do mine, but its been a couple of years anyway. As mentioned, can you get the drive shaft from the 9.75 donor truck?

 

the donor truck is 4wd and he is 2wd. i think the donor shaft would be too short.

as suggested before, see about shortening your driveshaft or find a donor truck 2wd with the 9.75 rear end.

 

looks like an aluminum drive shaft any drive train specialist should be able to shorten it not hard to weld aluminum just patience take three or four inches off will work fine measure the distance an mark where the slip yoke rides constantly or where it was with the other rear end

 

You can always check with a driveshaft shop and have them check out your shaft for balance. Try PST at www.pstds.com