Transmission slipping

I just bought a 92 Cutlass Supreme with a 3.1L V6. The trasmission is slipping. The reverse works well. But the drive grears dont want to engage. you have to shift it back and forth a few tims to get it to engage but then it slips again. When reving you can hear a rattling noise coming from the tranny. Any suggestions on what it may be?

If it is full, it's coming out for a major repair.

make sure the fluid is at a normal level...

if it's not then it probably won't be long until the entire tranny just shuts down and doesn't work...the same thing happened to me on my 95 cut supreme a couple weeks ago but i got the tranny from my 94 put in it and its good as new!

If its an auto than u have crapy clutches and bad sticking valves. the tranny is done. Get a good used one. real cheap.

If its standart. Simple shifter problem, bad clucht or hydrolic cylinder,clutch bearing, fork and pressure plate, bad synchros, worn out sleeves. It has to come out again too

Ok I have replaced the tranny and will fire it up tomorrow. Damn that thing was a bitch to get out.