2001 duramax/Allison Fresh basic rebuild (sorry DYI have to start somewhere) with the addition of transgo kit. At first multiple dtc for PSM and fluid leak at harness plug and limped. Bought new PSM and harness. Turns out I didn't have harness fully seated in case and connector fully connected. Had new parts so put them on. Now after setting overnight shifts into R and works can put into N or P and back to R and works properly but as soon as I put in D and back to R no reverse and shift indicator blinks and codes p1714. Drive shifts all 5 gears fine. Clear codes, shift to R, no reverse, R blinks and sets code, forward gears ok. Clear codes let set overnight and I have reverse again until I shit to drive. Sorry for the long post trying to give as much troubleshooting as possible. Any help is appreciated.
Allison Intermittent p1714 and no reverse
- Thread starter jeffro1976
- Start date
OK so if I don't get any replies before tonight I think ill drop the fluid and pan and put old PSM back on maybe new one is defective and sticking.
The NSBU switch and PSM are not agreeing on the shift selector position for some reason.
Possible NSBU out of adjustment or damaged o ring on the reverse pressure switch due to over tightening.
Possible NSBU out of adjustment or damaged o ring on the reverse pressure switch due to over tightening.
sorry was waiting on some customers. not at the ntsg manual but I torqued to that spec. the nsbu is about the only thing I haven't changed. I know the bolt holes are slotted for adjustment, is that easy to do? the ntsg manual shows the schematic for the nsbu should I be able to check that out with my fluke. My family owns a Welding supply and have been rolling cylinders and repairing welding equipment and machines all my life so if you have a need for something about that I can help out. In fact the first trans I did about 3yrs ago was an Allison at542 I think. that truck runs overloaded 5 days aweek. 90,000 later and still kicking. thanks for the help
Also my NSBU tried to adjust. Lined up the dashes and inslled while in neutral. switch moved so I went to line up I installed and I can move it 1/4" without any movement of the inner part of switch, sloppy on shaft (man I hate that) should be nice and tight right?:thumb:
Ok so when I said REL I was reading off the switch manifold. According to the ntsg book it is the reverse pressure switch which was the one that was coding and had TWO DAMN ORINGS. Every thing is good now. Thanks for the insight.