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straycatboat · 10-29-2016, 08:57 PM

I have a Monoco 2000 with ISC 8.3 Cummins 350 HP and Allison trans 3660 that won't shift out of neutral.
Dash says check trans, and shifter pad has all the code leds lit up at once. I noticed the engine rpm at neutral is 1200 per the gauge and I can't lower it with the idle up/down switch (just can increase it to 1500 rpm)
Allison man , can you help

BFlinn181 · 10-29-2016, 10:34 PM

The trans might be protecting itself and won't shift at such a high idle. Are you sure the cruise control is shutting off and not still pulling on the throttle? I had a similar problem once, I was trying to bump the idle up to get air pressure up, and accidentally reset the CC so it wouldn't return to proper idle. I had to sit with the cruise control manual and read how to reset it.

straycatboat · 10-30-2016, 07:02 AM

I'LL try that, I assumed it was off.

Old Scout · 10-30-2016, 07:16 AM

The Allison shift pad or ECM can be an issue but in this case, the high idle maybe the underlying problem. Most MH diesel pushers have fly-by-wire throttle control--the foot-feed in that system can be an issue.

straycatboat · 10-30-2016, 12:14 PM

Just checked the engine speed, its 650 rpm. The dash gauge reads 1200, so its not reading correctly.
I tried to read the codes off the shifter pad and its lights up and shows a 'o' real quick, thats it.
Tried to erase all codes by pushing the mode button 10 or more seconds and nothing happens/ beeps or changes.
The mode readout (small rect box above mode) is not lit and does not show anything.
I cleaned the Canon plug going to the shift pad and checked the plugs at the trans, all looks good.
What do you think?

BFlinn181 · 10-30-2016, 12:48 PM

I imagine the transmission gets it's engine RPM info from the same place as your dash tachometer. I'd check the engine speed sensor to see if it's correct. The lack of shifting out of neutral still sounds like it's self-protection.

96 Wideglide · 10-30-2016, 01:02 PM

Touching the brake pedal doesn't reduce your idle speed to normal?

BFlinn181 · 10-30-2016, 01:16 PM

Quote:

Originally Posted by 96 Wideglide

Touching the brake pedal doesn't reduce your idle speed to normal?

In the case of my Cruise King cruise control, by pressing the On switch 5 times followed by the Set switch, I accidentally retracted the cable reel, tightening the cruise control so my idle was set over 1,000 RPM. Turning it off did nothing to slack the cable, I had to read the manual to reset it to be slack when CC was shut off. Before I read the manual, to get the RV home I had to disconnect the cruise control cable from the throttle to return to normal idle. Not saying this is the OP's issue, but it could be. He'll need someone familiar with his engine to tell why it has a raised idle.

Old Scout · 10-30-2016, 03:00 PM

Electronic ignition, C/C and throttle control--so no cables. Hard to explain the different RPM readings--Bob may be right--tranny is reading the same high RPMs and wont shift. Or--might be time to call Transmission Instruments in Flower Mound, Texas. Send them your shift pad and tranny ECM--they will diagnose and fix each component for a flat fee. Good people, great service.

straycatboat · 10-30-2016, 04:50 PM

Wheres the trans ECM locate?
I found a relay Allison box near the shifter pad?

dbarton291 · 10-31-2016, 05:36 AM

If the dash tachometer is reading 1200 while the engine speed is actually 650, it sounds like you've got something besides transmission problems going on. The tachometer is not connected to the transmission system.

If the engine RPM was actually at 1200, the transmission would not go into gear assuming you have an electronic engine and no transmission throttle position in the system.

My guess is there's something, may be simple, maybe not, going on in the electrical system of the vehicle. This one is very difficult to point you to one specific location. Wish I could be of more help.

straycatboat · 10-31-2016, 04:56 PM

Here's the daily update>
Found a loose + wire in the forward elec box that feeds the VIM.
Bus now shifts and we take it down the road.
Stuck in first gear for a long time then shifts 2-3-4-5-6 Seems ok,
but when I try to downshift with the down arrows, says in 6th.
Stop at a light , now stuck in 6th.
shut engine down and it starts from 1st again.
Codes now available from keypad.
Get: OL-50
and D12215
Any Idea whats going on now?