Do-Not-Shift Light on Allison Transmission

[Sundancer268]

If I am reading this right the OP has a 1994 coach. With this vintage engine, I doubt that the engine has electronic engine controls. That would imply that with the mechanical fuel injection, the tack signal has to come from some where else. The most common place in that era was the Alternator and some engines if not using the alternator used a separate signal pick-up The Tack is where I would start first. Could just be a bad connection on the sensor or a failing alternator.

[williamhorn]

Hello everyone that has given me ideas to check out on my transmission not shifting.... I have checked everything and nothing works.. I am going to find a place to tow my motor home to get a mechanic to check it out.. Does any one know a good place to have it towed and get it checked out near Grove Oklahoma or Joplin Mo?

I appreciate everyone for taking the time to give me ideas.. I am just tired of messing with it now.. I need to get it fixed and get back to Colorado

Thanks again, William Horn

[wolfe10]

William,

Before spending the big bucks, have you verified with a digital voltmeter that the TWO 12 VDC positives are at 12 or more VDC? Easiest to check at the transmission side of the fuses. One is for ECU memory (i.e. is hot all the time) and is the smaller of the fuses (5 amp in many cases). The other fuse is only hot when the ignition is on.

If both of these are OK and ground for the Allison ECU is clean and tight, give John (one of my first posts) a call. All he does is work with Allison ECU's and shift pads.

Yes, plan C is to get an expert to look at it.

Brett

[williamhorn]

I will check this out. I did call John yesterday about rebuilding the ECU. I talked to the tech people at Monaco today. The first thing they said was disconnect the center wire on the battery isolater and use a multi meter and check the voltage for the alternator. Well there it was, jumped from 7 to 8 and that was it. So it is a bad voltage regulator or alternator. Tomorrow I take the alternator out and see if I can get it replaced. I am going to check the voltage regulator also. I sure hope this solves the problem. I will let everyone know. Thanks for all the help, it is much appreciated,

William Horn

[williamhorn]

I am wondering if theres an easy way to take this alternator out? Does any one have ideas?

Thanks,

William Horn

[dickandlois]

William,

Just posted a thread regarding Alternators. Boy oh Boy did I miss this one!

They can be a pain to remove, you NEED too tape up the red wire running to the battery positive connections.

Not knowing your skill level, take some pictures of the connections and label the wires so you can reconnect them correctly.

Detension the belt, use some penetrating oil on all the bolts. Loosen all the bolts. The hardest one is the bolt running through the hinge point ,if your set up uses this type mount.

They weigh about 20 lbs. and can be hard to hold and there is little more then room for one person. So work safe and maybe get someone to help hold the alternator.

Bottom bolts come out first and top ones last, this allows the helper to get a hand under it and out of the way of the area for the top one(s) so they can be removed.

Hope this helps.

Rich

[williamhorn]

Thanks Rich. I used to do this stuff all the time ( on cars that is) but it has been a long time. I have learned a lot on this though. It has really been hard. I sure appreciate everyone's help. I could not have done it with out everyone. I will let you know if this fixes the do not shift light.

Thanks again,

William Horn

[dickandlois]

Hi William,

See you have not been logged on for a few days,

Hope you are doing OK !!

Rich.

[williamhorn]

I sent my ECM to John, got it back and everything works perfect... This guy is really good. Thanks for telling me about him.

William Horn

[wolfe10]

You are welcome. Glad it worked out.

Brett

[TonyGA]

Hi everyone,

I was searching the web for some info, on the do not shift light on my 1994 Monaco RV and got into this page,

I have the the same problem, the light comes on and stays on, the trans pad is off is nothing there no lights,

but after 20 t0 30 minutes the display starts to blink. The N blinks for about 5 minutes and stops at that point

I can shift normally.

I have driven at least 1200 miles. but every time I stop it will go thru the same thing warm up for about 30 minutes.

Ihave not notice any changes and how the trans is shifting. I wast thinking maybe that was a problem with some trans sensor

that keep the trans from shifting until the trans oil got hot, but after reading the posts, I am lost.

I am going to access the codes. I just found some help on how to do it on the web, if any body can help with this

or had have problems like this your help will appreciated.

[wolfe10]

Tony,

Certainly, start by checking for diagnostic codes. Go to Allison's website for a list of the codes if you have them.

Also, check for power (12 VDC positive) to both transmission inputs and that connections at the ECM and shift pad are clean and tight.

[TonyGA]

Hi Wolfe10,

I went to work on my Dynasty Monaco 1994. I had the motor running for about an hour. When I started to see the the TWO N's

to blink, it took another 10 minutes for the N,s to stop blinking.

At that point I accessed the test mode and was able to pull 2 codes:

D1 69 32

d2 35 00

The first one i did not find anywhere on the Allison website. Tthe second one came out to be power interruption. Then after that the do not shift trans light came on and I was not able to get off the test mode,

I went ahead and checked the charging system alternator regulator clean battery post n it looks like everything is working fine. Today I went and started the engine, hoping that it will get to that point that will let me shift but this time the pad never blink or did any thing.

Are there two modules on this RV? Is the shifter pad part of ECM you point out to check connections at the ECM?

Also do you know where the ECM is located?

Help help help !!!!!

[dickandlois]

Tony!

D-1

69= Main Code and 32= Sub Code 32-Description = ECU, SPI communications link fault, Do not shift light (No do not shift light set)

Inhibited Operation Description = Induce COP timeout (reset ECU),DNA

D-2

35 = Main Code and 00 = Sub Code

00-Description = Power interruption (Code set after power restored)Do Not Shift Light (No do not shift light set)

Inhibited Operation Description = None (Hydraulic default during interruption)

The Set codes should not set a DNS Light on the transmission.

This is a link to a manual listing the Codes

http://truckroadserv...le-shooting.pdf

This link is to information to read and clear codes

http://www.allisontr...et=OM2683EN.pdf

Your Transmission might work like this, do not see where you listed the Model

Look for page 11 in the manual. The header bar may display page 18

This covers, How to display codes, How to clear Codes, How to Display Stored Codes and How to clear Codes.

Hope this helps.

Rich.

[wolfe10]

The location of the ECM is up to your chassis maker. It could be bolted to the electronic shift pad, or anywhere in the coach. If another Dynasty owner does not chime in, I would call Monaco Corp.

You will have two 12 volt positive wires to the ECM, one hot all the time for memory and the other hot from the ignition circuit (likely from a solenoid controlled (turned on/off) by the ignition switch/key.

Do other accessories that only work with the ignition on show the same failures/same timing? Things like the dash HVAC fan? If so, suspect the ignition solenoid or switch. Should not have anything to do with the alternator assuming you have 12+ VDC at the chassis batteries, as even with no charging, they provide a good supply of power to the ECM.

Brett

[TonyGA]

Thanks.

I will check those websites....

[TonyGA]

Hi Brett,

All the other stuff that works with the ignition on is working fine.

The only thing that I notice that is not working is the cigarette lighting, but that use to work without the key on.

I also check a fuse right at one the battery close to the terminal that powers the trans module according to some other info I research on the web.

thank Tony

[wolfe10]

Tony,

Were it me, I would locate the two wires going to the Allison ECM (the 12 VDC positives). Trace them back to the very last connection before the ECM.

Put a voltmeter on it and monitor it. See if power drops below 12 VDC when the ECM "has an issue".