I believe i shelled out my transmission... when in drive i floor it and just creeps??? all gears are like this including reverse. the truck is a 5.7, automatic trans and is . i could i tell what number on the tranny is the right one? there is m30 on it? New to chevy transmissions.

 

you may have a b.o. tranny, but first you might try replacing the nsbu switch. given your symptoms, this is a typical problem with gm trannys including the allisons. usually you lose gear indication in your shift column and autolock on doors, and in the end all you can get out of your tranny is 3rd and reverse. just a thought. on the allisons i know from experience you can pick them up online for $65, and about 15 min to an hour install time. good luck!

 

Make sure you have enought fluid in it too.