possible driveshaft going on 97

Heard a squealing noise that got faster as speed went up coming from underneath my 4Runner. Got home, put it up on jack stands, ran it in gear...The squealing noise is coming from the driveshaft. Cant tell if it is the slip joint on the shaft or the universal joints. I started to pump grease into the slip joint zerk fitting, but ran out in my gun....after it took quite a bit. (thought I had filled all of these about a year ago).
Tomorrow I get more grease, and will hit all of the zerk fittings, but I know I will be replacing something.

Should I take it to the dealer, pay them to diagnose the exact problem and order the part, but then take it back to install myself? They charge and arm and a leg...and I can go to NAPA to press in the universals if needed.

Check tranny & differential fluid levels, make certain it is not brake part noise.
then replace the U-Joints. Well check them first but most likely it will be one of the U-joints. Grab the drive line and push-pull laterally there should be no movement in the joint, 0, NONE (there will be some play in the slip joint but a little there is OK)

Found out the problem.
I had checked all fluid levels, and pushed on the U.V. joints, etc. It turns out the slip joint was dry. No grease.
Problem solved.
It made a pretty bad noise, so I had thought it would be something major.
thanks
matt

COOL!!!
I think I'll go grease mine today......

I think u-joints usually clunk when bad, rather than squeal.

I had the exact same problem. Several pumps of the grease gun to the rear slip-joint fixed it.