Truck is throwing CEL cant check cause havent had power to the obd2 port since i got the truck.. brand new transmission its been working just fine till the other day and it threw the CEL when it started acting up.. truck shifts and moves perfectly in reverse , 1st , 2nd but in drive its like in limp mode takes off in 2-3rd gear trans fluid is full and looks good problem came out of no where.. when i cycle the key several times then start the truck it still has a CEL but drives fine till it senses the problem again i have yet to drop the trans pan yet but i know it could only be a few things just not sure