After swapping out the whole rear end with a replica (minus the problem with the gears), I have noticed a wobble on the front end when I hit my brakes, especially if I'm going relatively fast (50+ mph) and slow down to between 30 - 40 mph. I don't see how these 2 things are connected, but I'm guessing that they have to be...it wasn't doing it before. Before the rear-end swap, I replaced the pitman arm and the truck was driving great. Is there something I need to check to correct the wobble? I don't think it's the death wobble that I've heard described, but I can feel it in the steering wheel and through my feet.

 

Are the drums on the new rear original to it? If they are, pull 'em off, and get 'em turned. Should make the wobble go away.

 

the drums that were on there had all kinds of grooves in them. The drums from mine did not, so we swapped them for mine. Mine are smooth, and I had previously ran sand paper over them. Other than that, we didn't swap anything out because the newer rear end was in better shape than my old one.

 

Does your e-brake work? If it does, SLOWLY apply it while moving along, see if your wobble shows up.

 

the ebrake works on the passenger rear tire, but not the driver's rear. well, it works somewhat, but not completely. My driveway is a slight angle. If I put the truck in Neutral and apply the e-brake, the truck won't move. we've tightened the adjuster but it seemed to my friend that the line may have stretched over time. He advised me to use a cheater clip on the ebrake cable that goes straight through, in front of where the rear passenger side connects to it. The cheater clip is supposed to take up any slack in the line.
BTW, we checked air pressure in all of the tires last night. The front was low, so we topped them off. That helped the wobble, but didn't clear it up completely.

I'll try what you mentioned and see how that does. Thanks.