2013 Transmission Issues


New Recruit
I have a 2013 Hino 268 with an Allisson 2200 RDS transmission.

It was recently having issues recognizing gears and gave the code SPN 2003 FMI 31 Address 3.

I replaced the TCM and harness which cleared the code and it seems to be recognizing gears correctly.

However, when you put the truck into any forward gear it seems as though the clutch engages momentarily, then slips back into neutral. At this point the gear indicator on the dash flashes. There are no codes present.

I've since replaced the internal wiring harness on the transmission, replaced the filters, and made sure it's at the correct fluid level. I've also cleaned all wiring connections between the Transmission, TCM, and ECM.

I've read that a bad NSBU switch could cause this, but was hoping for more input before I open the transmission up again.

Thanks for any insights!