91 f150 2wd changing u joints for the 1st time, any tips?:

 

Remove clips, use vise to support the cross part of u-joint and hammer away on shaft. I use a big C-clamp to push them in. Don't lose any needle bearings. If real rusty sand the holes in the yoke to aid instalation.

 

Use the u-joint that is designed for an aluminum d/s. Same as the regular u-joint; however, the U-joint for the aluminum d/s has a coating that resists galvenic corrision (a known failure mode when aluminum and steel components are coupled togerther).

For example: a 5-134X (Spicer) has an equivelent that has the coating for the aluminum D/S.

 

Is it ok to use in a steel driveshaf? Would using it help the joint last longer,(I live in the rust belt)?

 

The coated u-joint is available to prevent the galvenic corresion that occurs when you attach aluminum and steel components together. If you're D/S is steel, I cannot see where using the coated u-joint would hurt anything?

I was under the impression that all late model F-150 D/S were aluminum? Am I missing something here?

 

They aren't. Most I have seen are steel. Take a look,you will see a lot of rusty driveshafts.

As for things to do, mark where the driveshaft a yolk are in relation to each other. You don't want to reinstall 180 degs off as you could get vibration from the weight distribution difference.