Allison 2100 Code P0717

[millsrv]

Hello, We recently had a issue with our Workhorse W24 Allison Transmission. We just pulled out of a campground onto the main highway and the transmission would not upshift out of first gear. I noticed at that time that the amber transmission light, a gear with an explanation mark, was on. I had to pull over and shut off the engine twice before the light went out and all returned to normal. During the rest of our 500 mile trip there were no further issues.
The chassis is still under warranty and the repair shop just called and said there is a code, P0717. This code means no signal from the turbine speed sensor. Workhorse told them to look for a poor pin connection or a damaged wire. They are still in the process of locating the problem. Intermittent problems worry me, if the thing just stayed broken it would be easier to find the problem.
At least our trip was not ruined, so I guess it is good the problem went away. I just hope that the shop finds something and the problem never returns.

Has anyone else had this problem?

[ChrisNiemann]

sounds stupid but had the same problem when i replaced my transmission in my 1995 S10 Blazer. the gear that runs the electrical current to your speedometer also sends a signal to your computer letting it know how fast you are going compared to how hard you are on the throttle so the comuter can tell your transmission what gear it needs to get you going at the speed you're trying to go. I would have them remove the sensor and just replace it since it's a cheap fix to a possible horrible problem. if that thing goes out at 70mph with your foot in the throttle decent... well i'm not going to say what could happen but lets just say it won't be a fun ride and it will be a ton more $$$ than a $45 speed sensor...

don't want to scare anyone, but when i send an RV or Boat out of my shop, i let everyone know the goods and the bads so that everyone is aware and prepared for what "could" happen.

"Hind sight is always 20/20 but that doesn't mean we have to be blind going forward"

[millsrv]

Thanks for the reply Chris.
You are right about a inexpensive speed sensor being a easy fix. I will buy the part and at the minimum carry it with me. It takes about 10 minutes to replace the sensor.
As far as the shop is concerned, and since the chassis is still under warranty, they are following the instructions they receive from Workhorse. The removed the sensor and checked it's resistance and did a visual inspection. Then they checked the wiring and sensor pin connections. In addition they swapped the sensor with the output sensor and rechecked for codes. All is currently working normally no further codes.
On my next trip I will bring my scanner and a speed sensor.
If the sensor fails while driving the Trans. control computer will simply put the system into the "limp" mode and turn on the warning light. At that point I will readdress the issue.
Thanks again.