SO I replaced my U-joints over the weekend, and I had to make a special trip back to the parts store to get my U-joints, because the ones that they gave me for an F-150 didn't fit. The ones I tried first, the ones the book called for, was a 354. The ones that I ended up getting were a 331, listed for an F-250. I have a steel drive shaft, too, is this related? Why would my truck have U-joints that list for an F-250? Not complaining, guess they're just heavier-duty, but it makes me wonder. I have a 97 Supercab 4X4 Lariat with the 4.6.

 

The book at the store could be wrong, the counter man coulda messed up and B.S.'d their way out of it, there may be be a difference depending on wheelbase, or there may have been a running change that model year. Or they gave you 4x2 U-joints. No telling.

Whenever I go to a chain store like PepBoys, Murrays or Autozone I try to have the old part in my hand whenever possible.

It seems like some of the help just wants to hand you something to get you out of the store.