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Transmission won't engage

We are parked for the winter (last driven early November) and living in our unit.  About weekly I start the engine to circulate fluids, warm it up, build air pressure in the tanks, etc.  In November when I took it for a drive after sitting for about 3-4 weeks, the transmission was slow to engage but then did and worked well in forward and reverse. I thought at the time that fluid might have drained back from the active parts of the transmission (Allison World transmission - on a Cummins C8.3 engine.) and needed time to fill parts of the transmission for the torque converter (?) to work.

I don't often engage the transmission during my warm-ups but today I tried to do it and with the engine running (after about 10 minutes) I tried to shift into gear (foot on the brake).  Nothing in forward or reverse, nothing in Mode mode.  The buttons depress but there is no response.  My first diagnostic look will be fluid levels (haven't done it yet).  Any suggestions about where else to look for issues if the fluid level is up.  Last time I checked it was very clear and seemed to be at or above the fill line on the dip stick, but that was several months ago.  Ideas??
Woody & Sandy Lloyd
1993 Grand Villa
Unihome U280
Cummins / Allison
Build # 4379

Re: Transmission won't engage

Reply #1 –
When the key pad sits in the cold sometimes it does not respond while still cold.
Put a blow dryer on it and warm it up, may fix the problem.
They should all be this easy!
1995 U320C SE 40'
Jeep 4x4 Commander - Limited - Hemi
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Re: Transmission won't engage

Reply #2 –
Yes, agree more likely Key Pad than anything else if electronic pad - search the forum on those subjects and you will see a number of topics similar to yours. Often the warm up works, but sometimes after working a while, the pad still needs to be replaced (can't remember from prior threads if it can be repaired, but you will find that info in the topics found when you search.)

You may also want to search on short term storage, there is again a lot of info regarding what to do or not do when coach is not being driven for extended time. Consensus is to drive the coach at least 30 minutes every thirty days, or if you can't don't start the engine at all. When you run the engine without load, while you can get the coolant temps up to the operating range, you will not be getting engine temps hot enough to drive the water (condensation from the air in engine and crankcase from sitting) out of the oil. Which will ultimately accelerate internal corrosion of your expensive engine parts and at a minimum increase wear at each start up, when the bulk of engine wear occurs.

Our own Brett Wolfe whose opinion I greatly respect has quite a few threads you can find via search on this topic.

Good luck and let us know hoe the pad responds to heat from a blow dryer.
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
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1980 48' Westport MY (!/4 Share)

Re: Transmission won't engage

Reply #3 –
Use the blow dryer on the ECU also.  It should be located on the firewall below the steering column, it might also help to unplug the ECU, clean ( carefully ) the terminals and reseat the plug.
Gary B

Re: Transmission won't engage

Reply #4 –
Later models have a sealed keypad and do not have that exact issue
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Transmission won't engage

Reply #5 –
If the hair dryer makes a difference before you proceed you might want to call these folks.  Transmission Instruments
He repairs these pads and ECM units.  There are several forum members that have used these folks for repairs. He isn't cheep but good.  He also will help trouble shoot your unit to see if he can help you before you start removing parts.

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."
 

Re: Transmission won't engage

Reply #6 –

If you find the "hair dryer" trick works as a temporary fix, you may be in the initial stage of escalating problems.  We had a problem with our shift pad and trans ECU (2 years ago) that prevented the engine from starting.  Link below to my (long-winded) description.

Bottom line is I strongly recommend the service mentioned by Mike.  We sent our stuff in to him - he worked his magic - zero problems of any kind since.

One thing I do to when the weather turns cool and our coach is parked (and plugged in) for several days: I keep a small heater (see link) running under the dash in front of the driver seat.  It keeps the trans ECU and the touch pad warm, and (I believe) reduces the chance of condensation forming anywhere inside the case or inside the electrical connections.  May not actually be of any benefit, but I figure it can't hurt...

No start, with Allison "snake eyes" (Problem Solved)

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1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
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Sorento (or BOLT) on a Kar Kaddy SS
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