kwik kwestion,
what is the u joint size in a 1991 f350 auto 2wd for the rear axle?
Thanks.
(the one that between driveshaft and yoke on the rear axle)

 

Would it be different on SRW versus a DRW? Maybe someone will know your answer...

 

I was told an easy way to ID it is as follows. If it is held on with u-bolts and nuts, then it is a 1310. If it is is held on with straps and the bolts thread directly into tapped holes in the yoke, it is a 1330.

this might help as well.

U-Joint series identification