Due to the age of all 5R110's in circulation, many of them have bad original wiring harnesses that have been in use for over a decade and often longer. The OEM has since replaced and updated these items with successor part numbers, but further they should be replaced with every rebuild. It is a standard part of the rebuilding process to replace the internal wiring harness of the transmission. For your convenience, Next Gen Drivetrain™ keeps 5R110 internal wiring harnesses in stock! Got questions? Call in and speak to one of our experts.