I have a 2001 F-150 XL 4 x 4 4.6L with a bad alternator and a 2002 F-150XLT 4.6L back-up. Out of necessity I swapped alternators for resolve my charging issue. However, I notice a few inconsistencies between the two alternators and I'm in need of a few clarifications as well. 1) the alternator in the XL wasn't charging all the time...(12 volt then 13v and back again) so I swapped them in order to swiftly resolve my problem. The XL's pulley is larger than the XLT's (because my belt is smoking and frayed, which look exactly like the belt on the XLT). [I'm guessing that both trucks should have the 110A-130A alternators.] The regulator on the bad alternator is a F77U-10326-AA & I want to replace it on the cheap, but I can't find an exact replacement unless I go to Ford. I've seen plenty of Amazon & Ebay products that say they're a compatible replacement, but numbers don't match. (F784B, F795B, GR821, & etc.) Can you folks tell me if the G3-F794B is the correct replacement or offer a link for cross-referencing? I've also ordered a new Bando serpentine belt 6K-2512, but should I have ordered the 8K-2515 belt? Once again nothing under product specifications on ribs & presume the 8K has 8 ribs verse the 6K having 6 ribs? Thanks in advance for your comments and clarifications!

 

I'm no help.....but what did you find?

 

The easy way to tell is to put both trucks in an auto parts search for alternators and see what the parts house says.