Took the 84 brat for a little 4wd'in today... on the way home i noticed a rhythmic whooping / squeaking turn right... It seems to only happen in 4th gear goin about 35-45 mph.. Any suggestions? Ball joints? Let me know!

Eliminate the gear by speeding up to that speed and stick it in neutral. If it goes away its the trans, if it doesnt you probably have a wheel bearing or dirt in the brakes.

 

Try to:

Wash behind the wheels with a pressure washer/car wash sprayer. You probably have gravel between the spash guard for the brake rotor on the front if I had to guess. May require you to take the wheel off, hub off, rotor off and blow out the backside of the brake sys.

Cool I gotta do the front discs anyway.. so hopefully that will take care of it. (I know it's not squeaky pads.. I know the difference.) I hope it's something simple like dirt in the rotor or somewhere... If it's the tranny.. is it repairable.. or do i need a new one?

Check for a torn CV Boot too, gravel in there can make noises like this.

 

Not ball joints or tie rods. Doubt its the trans thats pretty low speed for 4th gear anyway isn't it? Also try engaging 4wd, backing up 15 feet straight, and disengaging 4wd. Make sure you are above 2000 RPM when in a drive gear (not low range) as lugging the engine can kindof make that noise.