Hello: just purchased our 17 Tiffin Phaeton in June. Only trip so far was from th FL dealer back home near Chicago. Took it out of our enclosed storage unit today for a trip to take our daughter back to college tomorrow and about 1/2 way into the 40 mile trip home as I slowed down for a stop sign the dash warning indicator lit and I noticed the trans didn't downshift. The indicator pad showed 5th gear and nothing on the pad I pressed would change that. Got the coach home in jut 5th gear and fortunately only 3 complete stop and start ups. After shutting it off in the driveway now it's stuck in neutral. Any suggestions from someone who knows Allison transmissions? We are supposed to leave for Oklahoma tomorrow morning so our plans to get our daughter back to college are all screwed up now. Tiffin was closed when we got home & our salesman was able to talk with one of his techs at the dealer which was also closed but their only suggestion was to cycle the main chassis breakers for the engine & trans off and on again. That didn't change anything. Really frustrating on a new coach with 2,600 miles. Thanks in advance.
2017 Tiffin Phaeton - Allison 3000 transmission stuck in 5th gear
- Thread starter dvredc5
- Start date
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8Muddypaws
Well-known member
That's bad. Your chances of leaving in the morning are near zero. It sounds like a trip to a freigtliner shop is in your future.
If I were in your shoes I'd be checking the connectors at the control pad, the transmission control module if I could find it, and the connector(s) that are on the transmission itself. Probably not much of a chance but might be worth trying.
If I were in your shoes I'd be checking the connectors at the control pad, the transmission control module if I could find it, and the connector(s) that are on the transmission itself. Probably not much of a chance but might be worth trying.
Gary RV_Wizard
Site Team
Call the nearest Allison shop and hopefully get some emergency help? Or a local Freightliner shop?
Loose connection on the relays back by the TCM, or the shifter pad, seem like a good bet, but finding it can be easy or a nightmare. As much luck as skill.
Loose connection on the relays back by the TCM, or the shifter pad, seem like a good bet, but finding it can be easy or a nightmare. As much luck as skill.
Thanks for the replies everyone. After talking with a chassis etc at Tiffin and a local truck center who works on Allison transmissions we found trouble code P0963. It's senses an issue with internal transmission fluid pressures. Typically too low and caused by a faulty pressure solenoid, wiring issue to the sensor from the PCM or a partially clogged fluid system in the transmission. Being only 2 months old and 2,634 total miles it's unlikely debris or dirty fluid causing the problem. I checked all the wiring leading to the trans and all looks fine - no signs of a critter chewing anything or something hitting the wiring and pulling something loose. When I reset and cleared the code it came back on in just a few seconds so it's not an intermittent issue. Plan B now, so unloading the RV into the pickup and will take our daughter back to OSU that way. Still trying to find a hotel room there that allows dogs since on short notice we have no time to make other arrangements for them. When we get back next week will look into trying a tech coming to our house and if they can't find anything it will have to be towed to their truck center. Not sure how they will get it there since we have a fairly difficult time negotiating our "S" shaped driveway with the coach much less trying to tow it too. It's also only accessible from he rear as it sits dead in the driveway. Thanks again for replies, really appreciate it.
Old Blevins
Well-known member
It seems unlikely to me this would occur on a new MH and you've probably checked it already - but just in case. That code can also be triggered by low transmission fluid level....
