OK, I called the 4 closest dealers and the results are:
#1. our techs use the PF 59 'cuz it's just easier to hand-tighten due to added length-shouldn't be a problem with it's use...
#2. can use the PF 59 but prefers the 46 due to internal differences, i.e. the port is different(?)-plus the 46 is what the factory recommends...
#3. they are the same just the 59 is taller-no internal differences. no problem with using the 59...
#4. no differences, thinks the 59 is used on 2WD but shoudn't be a problem on 4X4s...
So, I'm thinking that maybe the factory spec's the 46 since the 59 is longer and more likely to be damaged while off-road. Any other reasons or ideas?
I know most folks say size don't matter but a smaller filter will have less area to filter, right?
I may run the shorter 46 and then add a bypass filter setup-just to be safe. This truck may have to last 15 years like the last one did.
Any thoughts? Thanks to all, Snuffy