Transmission problem

[exportman]

I have a 2005 Southwind with 32,000 miles on a Workhorse chassis/engine with an Allison tranny. While driving at about 35-40mph I felt a clunk noise in the transmission with a slight bucking sensation. A yellow/Amber warning light came on which the Workhorse book calls the transmission fail warning light. Manual says take to a Allison dealer promptly.
I pulled over within 3 miles, drove around to find an Allison dealer in my toad and when I got back, I started up the RV engine and the amber light was out. Drove to the dealer 6 miles away.
This happened Sunday of Labor Day weekend. So, I am sitting at the Sacramento Truck Center parked outside awaiting their opening Tuesday.

So, that's the background. As I wait has anyone had any experience like this? Does it sound serious? Sure would love some feedback. Also if there is anyone out there from Sacramento with a recommendation for a dealer if this company won't work on my RV?
Thanks.

[exportman]

Sorry for not responding earlier to those who provided feedback to me in trying to figure out what was going on with the Allison tranny in my MH.
Since this happened on a Sunday Labor Day weekend we couldn’t get it looked at until Tuesday at the earliest. We drove it only a few miles, parked it and waited.
Cummins Pacific ( Allison, Cummins and Onan specialists) in W. Sacramento was our best option after talking with competitive repair places and also that we had good experience at their Fresno facility.
By noon on a Tuesday the diagnostic was completed. The tranny showed inactive codes (incorrect 2nd gear ratio) plus 1 or 2 other things. They replaced the solenoid screen and an internal harness. $77 in parts plus 5 hours labor including the diagnostic. They got me in and out the door in less than 36 hours. Giving a little extra priority to a traveler in a motor home away from home with a reefer full of food, a wife and 2 dogs was something I won’t forget.
Did it get fixed right? I think so because that day I headed I-80 to Reno and I could effortlessly climb up 6-7,000 feet. Now 6 days later I am in Yellowstone 900 miles away from the fix and all is well.

Thanks for reading and thanks for responding to my request of Sept 4th.

[Fulltimers]

Had mt TRANS light come on once. Shut it down and restarted it and no more light. This was about 5 or 6 years ago. Never happened again and everything runs great.

[Dr_Quick]

Automatic transmissions have a torque converter lock up mode at about 35 to 40 MPH. The ones that I am familiar with are operated by a solenoid in the transmission. Sometimes when solenoid goes to lock up, it can cause a shutter because solenoid is sticking and may need to be replaced. This can be sporadic, and may not happen again for a while. Some times a transmission additive may cure the problem.

[exportman]

Thanks for the response. The bucking I referred to was actually only a one time thing so maybe not the plugs. Guessing that the diagnostics reader will tell me lots more.
Just found out that the Allison dealer where I am parked works only on freightliners (diesels) so they may not want to even look at my RV. Did find a Chev dealer 9 miles away that works on gassers and Allisons so a call tmrw AM may determine if they will look at it for a diagnostic/fix

[randallb]

I will hazard a WAG and say plug wires are causing the bucking. When the engine bucks it is very possible for the trans to misinterpret the relationship between input and output speed / converter and tail shaft speeds, and set a light. The fact that the light went out indicates a temporary or intermittent problem that is no longer being seen by the control unit and possibly not recorded as a fault. Hopefully it will be plug wires and that you replace them with one of the good quality, ceramic coated boot, high temp wire kits available.