Classic/Antique Car Repair: powerglide trans, vacuum modulator, throttle linkage

Question
I recently purchased an all original 57 chevy with a 283 & powerglide trans. I am experiencing
some uphill slippage. Do you thnk band adjustment is a possible problem & do you know the adjustment procedure (specs.)

Answer
I am assuming by "slippage" you mean that the engine revs but the car doesn't take off the way it should.

As you may know, these were not quick take-off transmissions, so if you are used to a modern automatic, it might be just a matter of your getting used to it. But I am also going to assume that you know what you are talking about and there is slippage going on:

There are 6 things I can think of - low fluid, plugged filter, mis-adjusted linkage (both shift linkage and throttle linkage), bad vacuum modulator, and bands out of adjustment.

I'd have to sit here and type for an hour to tell you how to check all of those things, but I'll settle for the band adjustment procedure;  do that first, and if that doesn't help, get back to me and we'll talk about the rest of it.

The low band adjustment is the only one you can do without taking the back of the transmission apart, and the only one that will affect "take-off" unless the reverse band is set too tight (very unlikely unless someone has been fiddling with it), so adjust the low band as follows:

The low band adjustment is on the left (driver's) side of the transmission, and sticks out of the case about 2 inches forward of the domed cover, about half way from the bottom to the top of the main transmission case.  Loosen the lock nut, if present, while holding the center bolt head with another wrench, then, with the lock nut way out of the way, tighten the adjuster with a torque wrench to 6 foot pounds torque, then back it off exactly 3 turns.  Re-tighten the lock nut now, without moving the adjuster.

Now see if the situation has improved.

If it has not, drop the pan and inspect the filter - if it is plugged with crud, you will need to clean it thoroughly, and replace the fluid with fresh Dexron/Mercon fluid.

I'll wait to hear from you before getting into the rest of the possibilities.

These are very durable transmissions - I have one in my old tow truck which has been treated roughly by me and others since 1960 or so, and it has never given any trouble at all (but they are sloooow on takeoff!)

Dick