I replaced my old trans, which was in my 93 gmc suburban k1500 because 3rd and 4th were slipping really bad. I did this in February.
A couple of days ago , when my truck reached operating temperature it started shift dancing between 3rd and 4th and then down shifted to 2nd and stayed their. When I was almost home it did shift to 3rd but then just stayed in 3rd. So I did some goggling and it sounds like a electrical problem. So I unplugged the battery for about 5 mins then plugged it back in and the truck ran fine. I did notice some differences with the old and new trans. The stock one had a K stamped on each side of the bell housing. The rebuilt trans only had M30 stamped on one side. The dust plate bolt pattern didn't match, so I lined it up and clamped it on.



Any ideas would help
Thanks

 

the (k) only means its a 4 wd case, it should have a thicker bellhousing and large cap screws that hold the dust cover on. there is a year break on the 4l60e trans as far as the converter is concerned if yours had a pwm cast into the front pump make sure the replacement has the same. the break is in the 94/95 model split. the wireing is different inside the trans