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JF1957 · 05-24-2016, 07:08 PM

Tonight we just arrived from a long week end of camping, i drop my wife at our house door before going park the motorhome. When i push the D button the left digit write D while the right one write N and the MH wouldn't move, go back in N, both digit says N, i try the R and now the left digit write R and the right says N and the MH wouldn't back up. This is an Alisson MD3060 6 speeds tranny with an Cummins 8.3 300hp, anybody have an idea of that issue ?

tmw188 · 05-24-2016, 07:13 PM

Your motorhome doesn't want to go back into storage, it's being stubborn:/

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dbarton291 · 05-25-2016, 06:33 AM

There is an inhibit that is preventing the TCM from commanding range. It may be it thinks engine RPM is too high, the service brake isn't on, jacks are down, etc.

MaverickBBD · 05-25-2016, 03:29 PM

I assume you tried resetting by shutting down and restarting.

JF1957 · 05-25-2016, 08:13 PM

Quote:

Originally Posted by MaverickBBD

I assume you tried resetting by shutting down and restarting.

Yes and after restarted it finaly move.

Pusherpilot · 05-27-2016, 10:14 AM

Quote:

Originally Posted by JF1957

Yes and after restarted it finaly move.

Amazing!!!!! The Microsoft "fix" works on motorhomes too. The problem I described on my other post can be "fixed" for a short while by using the shutoff and reboot process----------sometimes.

JF1957 · 05-27-2016, 06:37 PM

Quote:

Originally Posted by Pusherpilot

The Microsoft "fix" works on motorhomes too.

I will like to know a little bit more of it !!!

MnTom · 05-28-2016, 07:52 AM

Quote:

Originally Posted by JF1957

I will like to know a little bit more of it !!!

He means rebooting the transmission computer (TCM).

Pusherpilot · 05-28-2016, 10:35 AM

Quote:

Originally Posted by JF1957

I will like to know a little bit more of it !!!

The Microsoft "fix" is shutting the computer down and turning it back on to "reboot" anew, hopefully dumping all the bad code that locked it up. It reloads a new clean set of the OS.
ron

Skip426 · 05-28-2016, 10:49 AM

Quote:

Originally Posted by dbarton291

There is an inhibit that is preventing the TCM from commanding range. It may be it thinks engine RPM is too high, the service brake isn't on, jacks are down, etc.

I too think that RPM would be the issue here.
If your throttle pedal is floor mounted , check for a rusted hinge that may be holding the RPM up , 75>100 RPM too high is all that the Allison ECM would need to see to stop the shift into gear.
Throttle return springs on the injector pump also a possible.
I'm assuming from the year this is a mechanical Cummins engine.

MaverickBBD · 05-28-2016, 10:54 AM

I concur it sounds like a speed sensor to me. Had a friend have one go bad on a brand new motorhome. He called 1.800.FTL.HELP and they walked him to the pin in a wiring bridle.

JF1957 · 05-28-2016, 12:54 PM

I have a D1 2112 code on the tranny shift pad.

scampers227 · 05-29-2016, 07:13 AM

Copied from Alison codes list.
21 12 throttle position sensor, failed low

barmcd · 05-31-2016, 01:31 PM

Does the Allison use the same position sensor the Cummins engine uses? It's connected to the accelerator pedal mechanism. I had the same type of code, only it was the engine ECM spitting it out, not the Transmission. The coach would go into gear, but the engine wouldn't go above idle when you pushed on the pedal. It was a fairly cheap DIY fix at ~$125.