First thing you wanna do, since its an automatic, how many miles are on it? Then after you find out the mileage, ask the previous owner if its had a trans fluid and filter change, and if not, change the fluid and filter. If that dont help, it needs to be overhauled, with new clutch packs-steels and frictions. While your in there(if overhaul is needed) for the love of GOD thouroughly CLEAN the valve body, and DO NOT let any contaminants get into the valve body, INCLUDING lint from standard shop rags. Any kind of contaminants in a valve body will cause it to NOT function properly. It WILL save you issues later on post overhaul. Im A.T.R.A. certified to work on automatic transmissions. Ive been through enough to know how bad they can get. The one in my truck had a fried 3-4 clutch at one point in time coz some overhaul shop rebuilt it WRONG, and the trans had a little more than 25,000 on the overhaul. My bud once had an 88 F250 that had a C6 transmission, and when we tore that one apart, we both are shocked TO THIS DAY that that truck even was able to MOVE because of how bad the internals were, for instance, one of the sprague(one way metal on metal) clutches was destroyed beyond its acceptable limit. Last week I did a trans fluid and filter change on my dad's 1966 Chevelle, and I found plenty of clutch material and metal in the pan, but since its a Powerglide, it didnt worry me simply because the powerglide was one of the best autos that GM ever created, and they are simply blow up proof and bullet proof, coz after I finished with the fluid and filter change, it shifted perfectly, despite all the metal and clutch material I found in the pan upon removal from the car. Ive seen overheated clutches, destroyed clutches, fried ones, where there was no friction material left on the frictions, and other bad news inside of them.
Last edited by m20enginebuilder; 07-29-2012 at 01:08 AM.