So I just bought a 92 f250 with a 351 for a plow truck, only sketchy issue is the 4wd, it works it has new hubs but the problem is the lever is very stiff going into 4wd and will not go into 4L any ideas... I'm thinking linkage from sitting but don't have much experience with fords.... any help would be appreciated....Thanks

Also if anybody has any info on how to decode the trans/t-case/ axles and gears so I know what I'm working with

 

The shifter must be pushed down to shift to neutral and 4L as instructed on the ****. The shifter has a small outer housing and a inner shaft that moves inside up and down, held in the "up" position with spring tension. It is normal for it to freeze up from lack of use of those two positions, neutral and 4L. Most people use 2 and 4 hi so the lever is not pushed down enough to keep it working freely.

If you look at the shifter from under the truck you will see the tension pin and the "gates" it indexes into for each position in a piece of flat stock, a long slot for 2h to 4h and a single small notch for neutral and 4L positions.
The inner shaft is protected top and bottom by a rubber boot, carefully clip the zip tie for the top boot and spray the heck out of it with your favorite penetrate. You may also have to do it from the bottom. You may even have to remove the shifter to to it, don't break it, it is kinda pricey to replace as a unit.

Once freed up use new zip ties to keep the boots in place.

As for your other question, the sticker in the drivers door jamb. It will answer some of that by searching this forum to decode the codes on it.

The axles should have a metal strip on one of the pan cover bolts with the axle ratio info on it.

There are other ways to tell if its gone but start by looking for it.

 

your axles shoud be sterling10.25 rear and d50 ttb front