Just swapped a transmission into my 07 5.9. Its a full billet DTT with a single disk tc. Drove about 100 miles with it before I had to hook up to a stock trailer. Drove out fine, on the way home the check engine light came on. Pulled over at the whataburger to see what it is. Plugged in smarty to check the code and it said "TCC O/D SOC performance" code "P1740". It was running fine and when I got back on the road I ran through the tow hall (worked perfect) and o/d (worked perfect). Didn't have a big load, just one stick in the trailer, so I kept on trucking and left the code.

Questions: Is this something that the new trans has caused? Is there something that could be wrong with the trans? Should I just clear the code and not worry about it?

 

Clear it, I would not be too concerned if it was running fine. But I would call the builder or DTT to get an explanation ASAP. Good luck.

 

Im pretty sure there is nothing wrong with the trans, I have been running it for 60+k miles in my 06. Just swapped it into my new 07. So this is not a new trans, its plenty broke in and it never through a code on my old truck (although I didn't install it) that I know of.