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 keeps 5R110 internal wiring harnesses in stock! Got questions? Call in and speak to one of our experts.