TRANSMISSION SEEMS TO SLIP AT TIMES AND MAKES A SOUND. IT DOESNT DO THIS ALL THE TIME

Time for a transmission rebuild

sound like it may be a shifting seloind

When was the last time you had the transmission filter and fluid changed? I f you haven't ever or it's been more than a year or two it can cause the transmission to slip.

Sounds like your transmission has come to the end of its life. You can try getting the transmission flushed , and an additive I.E. No Slip added. That might cure some of the problems but obviously if its slipping the clutchs inside are worn out and transmission needs an overhaul.

Sound like oil pump in torque converter is on its way out. Time for a rebuild/replacement.

There is only one way to go: replace the auto transmission. Buy a rebuilt one is Ok.

check the transmission fluid, it may be low, if not look and see if it looks black if it does you may need to change the transmission filter and fluid

your transmission is more than likely going out. I do know that between 1997 and 2002 the transmission that went into GMC vehicles have had bad reviews. I had a 1997 Pontiac Grand Prix that was doing the same thing and the transmission went out on me. I am not positive to this but i have read the research and it has happened to me before.

The 1st thing to do is have a test run on the transmission control module to see if any trouble codes are present, next have you ever serviced the transmission, fluid and filter change, should be done at 60,000 miles, on occasion this can cure problems like yours.

sounds like your automatic transmission is beginning to slip. I would look into getting a transmission fluid change maybe the fluid is sludged.