Allison Transmission

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UndertakerII

Member
Joined
Aug 20, 2012
Posts
12
I have an older (1994) Monaco motorhome with the cummins 5.9 ISB engine and allison 6 speed transmission. I've put about 300 miles on it since I got it and all has been good. I started it up yesterday and the temperatures here were around the freezing point and when I went to put it in gear via the keypad initially I could only get it into reverse and back to neutral. After a little bit of finagalling I was able to get it to engage into low gear and back to nuetral but it still isn't real co-operative. My question is were do I look first? Could the selector pad be the problem? When you press the buttons to engage the various gears you hear a beep when it engages but when I'm having the problem with the forward gear selection there is no beep! Hope someone can understand what I have just typed. Thanks! Kevin 
 
My first check would be for sufficient transmission hydraulic fluid. It sounds as though the tranny was so cold it had trouble engaging gears until it warmed up a bit. To some extent that is normal but it is exacerbated by low tranny fluid or dirty fluid filters. Do you have any records that indicate when the transmission was last serviced? If not, a fluid and filter change would be a good investment, I think.
 
Yep, what Gary said. Plus I would look into putting in Allisons now standard "Transynd" fluid.  It is their gold standard now and helps trans work smoother and last longer.  The shop you go to should be able to tell you if it would be compatible with your year of trans.  It is a bit more money, but well worth it in my opinion.
 
Just to follow up I did check the fluid and it was ok. The weather has warmed up some here so I let the engine run for a bit and get some heat in it and the trans seems to be a little happier now. It didn't want to engage drive right away but after running it for about half an hour it appears to be workink ok. So maybe the old girl is just cold blooded. Thanks all. Kevin 
 
I would still HIGHLY recomend a fluid change if it hasn't been done recently.
 
Rocket said:
I would still HIGHLY recomend a fluid change if it hasn't been done recently.
If you're going to go with Transynd, I would drop the transmission to get all the fluid out of the torque converter and have the tranny broke open to change the filters. We just had it done on a 1996 Holiday Rambler and the fluid cost as much or more than the fillters and labor. Less than $300 for the whole job and peace of mind.
 
Check the fluid level,  Had a similar experience with on 06 Chevy with the Allison.  In cold weather, shifted funny once.
A couple week later in a 20 degree, didn't want to shift out of low gear.  Finnally, warned up and started act right.  Took it in to the dealership and it was several quarts low.  Weird cause I had them Flush/Change the tranny fluid  a couple thousand miles before. No leaks on the floor so I only assume they didn't refill the tranny with enough fluid.
 
UndertakerII said:
I have an older (1994) Monaco motorhome with the cummins 5.9 ISB engine and allison 6 speed transmission. I've put about 300 miles on it since I got it and all has been good. I started it up yesterday and the temperatures here were around the freezing point and when I went to put it in gear via the keypad initially I could only get it into reverse and back to neutral. After a little bit of finagalling I was able to get it to engage into low gear and back to nuetral but it still isn't real co-operative. My question is were do I look first? Could the selector pad be the problem? When you press the buttons to engage the various gears you hear a beep when it engages but when I'm having the problem with the forward gear selection there is no beep! Hope someone can understand what I have just typed. Thanks! Kevin
My question is, are you having trouble with the selector pad going into gear?
In other words, is the selector showing it in gear or neutral?
The reason I ask is that my shifter pad is tough to get it to select when it is cold. I have to run engine and furnace to get cabin warm. After that it works fine.
 
Did you use your engine preheater to warm up the oil and such?  We put ours on a few hours before driving so there's less stress on everything.  Cold can cause some wierd problems!

ArdraF
 
I've checked the fluid and the level is good. The transmission and all other fluids and filters were serviced in the last 1000 miles. I'm thinking it has to do with key pad and the temperature. Not sure if the pad is known to act like this in extreme cold so I was throwing it out there to see if anyone else has had this type of issue. Kevin
 
I have never had a problem due to cold and we have driven in very cold temps, -30? F. 

I suspect a switch in your pad is dirty or failing.  I have not been inside that assembly so  have no advice on the actual access or possible repair.  If the switch is a classic micro switch, a shot of De-OX-It, obtainable at most Radio Shacks under their own brand should do it.  Other than that, I have no suggestions.
 
mdbass said:
If you're going to go with Transynd, I would drop the transmission to get all the fluid out of the torque converter and have the tranny broke open to change the filters. We just had it done on a 1996 Holiday Rambler and the fluid cost as much or more than the fillters and labor. Less than $300 for the whole job and peace of mind.

$300 to drop one of those Allison beasts + do the service? I need to know that phone number. I would have thought it would be much higher just to drop the transmission.
:)
 
I recently had a problem with my MH 3000 Allison transmission.  In the end it was only a bad connection at the power cable.  As part of the process of finding the problem I bought a shift selector console to substitute and eliminate that part as the problem.  The Allison list price for the console was $850.00.  Colaws salvage sold me one for $150.00. Trying It showed that my console was fine.  I then thought I needed a transmission computer module and Colaws even agreed to take it back in trade for the module.  As it worked out a more experienced technician found the bad connection and I did not need the module.  I also chose not to cause Colaw to lose a sale so I keptthe console as a spare.  If anyone wants or better yet needs this part, they are welcome to it.  Only request is that they pass on some other part when someone needs it.  I am a beliver in the sayings "What goes around, comes around" and "paying it forward".  I am posting this offer because maybe the console is the problem this original poster has.

Here is a picture of the shift console to see if it is the same one.

http://i279.photobucket.com/albums/kk121/HueyPilotVN/001-47.jpg
Edit: Fixed link.
 
Hueypilot, Do you know where your bad connection was located? Was there a specific spot or junction that I should look for? I may be interested in your offer (for a price) if the shifter console is the one like mine. It's just been a little too cold here lately to look over mine! Thanks. Kevin
 
I had a similar problem back in July. There was a loose wire connection inside one of the large multi-pin connectors that connect the Allison ECM to a junction box that contained fuses & relays. This junction box (mounted within a foot of the ECM, in  a rear compartment) in turn connected to the shifter and tranny itself.  Once it was finally located (just by repeated wiggling of wires and connectors), it took all of 2 minutes to fix.
 
The specific spot where my loose connection was is shown in this picture.

http://i279.photobucket.com/albums/kk121/HueyPilotVN/002-44.jpg

It is in the battery compartment and is the large cable on the right below the in line fuses.  The nut was loose and you had to feel the cable to find that it was loose.  It looked fine. 

I do not want to negotiate any price with "The Undertaker".  lol  So the price is still "Free".  Send me a private message with details of where to send it if you think the shifter is the problem.
 
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