V6 engine,model U trans.240,000 miles.No preveous problems with trans. I was slowing down and the truck started down shifting and up shifting,O/D light started flahing! Pulled over to check fluid level, it was good .Put it drive to go again and the truk would not move,reved engine and it slamed into gear. Got home change oil and filter, light quit flashing and it seemed to drive fine until it warmed up. On deacceleration,it down shifed hard and up shifted and down shifted again. I have'nt had it checked for any codes yet. I'm not sure it will make it to the shop!!!!!WILL SOMEONE PLEASE HELP ME??????????????

 

You need to check the codes. You need a high end scanner to read transmission codes, the ones the parts stores use won't do it.

You may have to use manual 2nd to get it to the shop.

 

OK ,thanks alot for your input and I will let you know what I find out!!!!