Intermittent bumpy 1-2 shift Archives - Transmission Digest
Blame it on Missing Harness Retaining Clips

The subject vehicle that was fitted with one of our remanufactured transmissions six months prior showed up at one of our repair locations recently, with the customer concern of an intermittent bumpy 1-2 shift, and a low-power lugging sensation along with a CEL on. While performing our initial evaluation, we found a P1860 code stored in history, but not current. During the road test the truck was working well with no clear signs of what set the DTC, but after several minutes of driving it started to act up. The TCC was applying right on top of the 1-2 shift, but according to the scan-tool data, was not being commanded on by the ECU.