Okay so after about a year the 2nd-3rd gear still slips sometimes, ive replaced the filter, fluid, had the bands adjusted several times, i know whoever had the truck before me was rough on it because he was a farmer and the tranny fluid was pitch black. I know im getting the tranny rebuilt sooner or later when the money is right, but is there any damage that its causing or is the damage already done? it doesnt do it all the time.. and its not too harsh but i can feel it and hear it, sometimes it rubs/grinds up a hill as well.

 

sounds like mine. if its on its way out it will get worse even with trying to save it. try putting some trans additive in(not sure what kind is recomended). be glad its not like mine where it got stuck in 3rd gear.

 

Any slippage is bad and can cause more problems. It is best to rebuild it now before it dies on you in the middle of no where and leaves you stranded with a higher tow bill then the repair bill.

 

If the fluid is at the correct level, you changed the filter and adjusted the bands, and still has the slip... it is just going to get worse. Crazy made a good point, it is probably just a matter of time before it leaves you stranded. But, if you must drive it I suggest making friends with someone that has a car trailer lol.

You could try an additive like Shadow said, such as Lucas Stop Slip. The stuff is thick and will increase line pressure that helps against drum seal leaks (which could be happening since the trans was obviously neglected by previous owner), but if it is grinding I don't know that it will even make a difference.