Ok, so I know it isnt a bonneville, but I have a relatively generic ? that someone might know the answer to. So on my truck, i has a 4L60E transmission (4 speed Auto, 4x4) anywho... when its cold, shifting into reverse is fine, but if its warm, it Jerks HARD, and today when I was putting it in reverse, it made this AWFUL grinding noise that didnt stop till I put it in park, and then back into reverse, it kicked, but no grind.. Now, going forward is just fine, smooth upshifts and smooth down shifts, Transmission fluid is a perfect color, and level... and seeing as its a used car, no warranty .. I think i just got hosed, but let me know if it might be something simple.
THANKS!!!!

EDIT: Just realized this may need to be in the lounge.. if the mods would be so kind if appropriate.

It might be the wrong type of transmission fluid in the case. If it doesn't have the proper friction modifiers in it, the clutches can slip or bind. Also, check to see if it grinds when you drop it down into 1. There is one clutch that works that and reverse.

Thanks, I tried 1st and no grinding, and the reverse only did it once (so far) it still clunks really hard going into reverse @ operating temp, and I noticed that It seems to be OVER filled, the stick is covered above the like bent metal part (wayyy above crosshatches etc) and there is tons of drops out the bottom, like its leaking somewhere... I may have to get some leak sealant, or maybe i should quit being tight and take it to a shop

Well, I am not sure if this could be a symptom of being overfull, but that can cause serious problems. But before you start draining fluid out because it isn't the proper level, ensure that you are properly checking the level. You probably know this, but you can't just check it like engine oil. If you don't know, check the owners manual.

basically what he is saying is that you have to check the level when the engine is hot and running. The fluid is fully circulating then and it will give you the most accurate level. The level is going to be over by quite a bit if you check it with the engine off and even more so if it'* been sitting a while.

thanks, knew that its over full when @ operating temp & running, and sitting on level ground, all factors that can effect level. And dang it the oil is filthy, I thought they were sposed to take care of those things... I am still not going to drain any out until I have the time to read up on how to do so safely for that trans, and have some other things to put in @ the same time.