Binding in 4wd - more than usual

[FSRslug]

I searched and was not able to find what I was looking for.

I have an 05 ranger XLT 4L. Last weekend when I tried to put in in 4wd it was very harsh to engage and didn't feel right. After I got home i started to look online to see what I should look at, but didn't get too far with that. My fiance took it to work the next morning and said it was popping and grinding when in 4wd. She made it to work and back fine in 2wd.

Anyway, I got under there and can see that the pinion seal is leaking. It has flung oil all over the bottom of the truck. I checked the front diff fluid level and couldn't find any. I put a quart of oil into it last night before it started to drip out the fill hole. Drove it around and it still feels like crap. I have no idea how long the fluid was low or empty. It feels fine in 2wd, but horrible in 4wd. It feels like it is binding a lot. I know that some binding is normal on hard surfaces, but it binds even in a straight line. Tires are new and the same size. All the boots look fine and I see no leaking form anywhere else. When I turn the wheel if feels like the brakes are being applied.

I am pretty sure stuff in the diff has been damaged since it was driven without fluid, but I m not sure what to look for.

Can anyone guess what is damaged, and what it might take to fix it?

 

[FSRslug]

Not sure what the deal was, but after the seal was changed, it drives fine.

 

[feellnfroggy]

When mine started doing this, it took about 2 days and it locked up on me in 4wd. Once I got it in two wheel it was fine, but only after I took my hubs off. I have welded hubs from THATGUY, he got tired of his autos breaking and welded them for fulltime lock. I have a crack/hole in hte tailshaft of my front diff, the entire front case needs to be replaced. Might oughta get under there and do a visual.