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Xjaywalker · 09-20-2015, 09:25 AM

Just went through Big Horn Mtns and was doing some manual shifting to slow the beats down. Accidenatlly shifted into economy mode and then I started feeling a hard shift (or hard knock from the rear). When I noticed I had shifted into economy mode I switched back, but the noise continued. I am parke in an RV Park now and have not tried driving it this morning.

Anyone expierence this? I saw on line that you can reset the ECU by unplugging 2 cables on the ECU. Anyone know if this works? Or should I take it in to a Allison shop?

Thanks in advance.

Skip426 · 09-20-2015, 11:20 AM

The Allison ECU could just have picked up some shifting traits from the manual down shifts and need to re-learn it's normal smooth pattern.
You could check for codes using the key pad, but until you've driven the coach for a few hundred miles, JMHO; I wouldn't be in a panic to get it to a shop.

Xjaywalker · 09-20-2015, 11:45 AM

Quote:

Originally Posted by Skip426

The Allison ECU could just have picked up some shifting traits from the manual down shifts and need to re-learn it's normal smooth pattern.
You could check for codes using the key pad, but until you've driven the coach for a few hundred miles, JMHO; I wouldn't be in a panic to get it to a shop.

Thank you. I had not driven mountains like that it this big of a rig (40ft) with a tow vehicle. I read my manual also, it sounds like it would take a lot for me break the trany. lol.

I will run the program and look for codes. Thank you again, I was worried there for a minute.

Larry & Vicky

Skip426 · 09-20-2015, 12:18 PM

Quote:

Originally Posted by Xjaywalker

. I read my manual also, it sounds like it would take a lot for me break the trany. lol.
Larry & Vicky

The electronic controls on the engine and transmission , along with their interaction , will do everything they can to protect themselves and each other.
Note; a trans controller disconnect , would revert the controller to basic ' Learn " mode and there would be rough shifting involved until that was completed. I would only consider a disconnect to clear a code after repair , and sometimes that won't work.

jacwjames · 09-20-2015, 12:51 PM

If the knocking continues it might be a problem with the driveshaft. All the energy that is transferred with a sudden hard downshift my have done something to a U-joint. If the sound continues I'd inspect the driveshaft to make sure there isn't a problem.

dbarton291 · 09-21-2015, 07:57 AM

The trouble codes and adaptive parameters are written into EEPROMs so the information stays there even after a power interrupt.
The codes can be cleared using the shifter or Allison DOC. To reset to fast adapt, you must use Allison DOC.

Xjaywalker · 09-21-2015, 08:01 AM

Quote:

Originally Posted by dbarton291

The trouble codes and adaptive parameters are written into EEPROMs so the information stays there even after a power interrupt.
The codes can be cleared using the shifter or Allison DOC. To reset to fast adapt, you must use Allison DOC.

Ran the test on the display. No codes. Resumed driving and it seems to be back to normal. Thank you

Xjaywalker · 09-21-2015, 08:03 AM

Skip426, thank you for the data. Ran the test on the display and no codes. Took off this morning and she is back to normal shifting.

Appreciate your help.

Xjaywalker · 09-21-2015, 08:05 AM

Quote:

Originally Posted by jacwjames

If the knocking continues it might be a problem with the driveshaft. All the energy that is transferred with a sudden hard downshift my have done something to a U-joint. If the sound continues I'd inspect the driveshaft to make sure there isn't a problem.

Checked the drive shaft and tranny for anything unusual. All good. Took off this morning and she is shifting normally.
Thank you