Community Forums

joeplazek · 12-18-2013, 04:53 AM

I have a 1996 Monaco Signature with a Cummins M11 450eplus and a Allison HD4060 transmission. The problem I have is the Transmission Computer does not seem synced to the engine RPM's. It will downshift to a low gear and lug. Does not seem to run the RPM's up far enough before shifting. Will search back and forth 2 cycles before settling in to the gear it feels it wants.

What I am looking for is some input on a company or person that knows these computers well enough to diagnose the unit. It has been to Cummins and Allison and all reports are that everything is fine (of course). If it is fine I can live with it but if it can be improved lets improve it. OR is it the engine computer not giving the right info to the Transmission??

joe

Steve Ownby · 12-18-2013, 05:44 AM

Quote:

Originally Posted by joeplazek

I have a 1996 Monaco Signature with a Cummins M11 450eplus and a Allison HD4060 transmission. The problem I have is the Transmission Computer does not seem synced to the engine RPM's. It will downshift to a low gear and lug. Does not seem to run the RPM's up far enough before shifting. Will search back and forth 2 cycles before settling in to the gear it feels it wants. What I am looking for is some input on a company or person that knows these computers well enough to diagnose the unit. It has been to Cummins and Allison and all reports are that everything is fine (of course). If it is fine I can live with it but if it can be improved lets improve it. OR is it the engine computer not giving the right info to the Transmission?? joe

Is this a new to you coach and this is behavior that has been present as long as you have had the coach, or have you had the coach for some time and this has just started to happen? How long since a fluid/filter change? Do you know if the fluid has been changed to a TES295 fluid or it's still a Dexron III clone?

Depending on the answers to these questions, I would change the fluid/filters. Whether you change to TES295, if that's not what's in there, or not might depend on how long you expect to own the coach. By aware that if you don't have TES295 and change to it, it will take 2 back to back changes to be considered 100% TES295 and go by that service schedule.

I have seen many odd shifting situations be solved by a fluid/filter change. If you go this route you might want to send a sample of the old fluid to JG Lube Services so you know what's actually in there and if there are any wear metals or contaminants in the fluid.

palehorse89 · 12-18-2013, 06:34 AM

Hi Joe, look and read page #32 here http://www.rvtechlibrary.com/transmi..._operators.pdf and read on "adaptive shifting". I once read on here instead of going through the sequence on page #32 disconnecting the battery terminals for 2 days or so will clear the shifting program in the TCM that it has learned. Maybe a reset of the TCM will help you with this, and maybe Steve can enlighten you a little more on what I have posted. What Steve posted would be a starting point.... filters & fluid.

joeplazek · 12-18-2013, 12:56 PM

Quote:

Originally Posted by Steve Ownby

Is this a new to you coach and this is behavior that has been present as long as you have had the coach, or have you had the coach for some time and this has just started to happen? How long since a fluid/filter change? Do you know if the fluid has been changed to a TES295 fluid or it's still a Dexron III clone?

Depending on the answers to these questions, I would change the fluid/filters. Whether you change to TES295, if that's not what's in there, or not might depend on how long you expect to own the coach. By aware that if you don't have TES295 and change to it, it will take 2 back to back changes to be considered 100% TES295 and go by that service schedule.

I have seen many odd shifting situations be solved by a fluid/filter change. If you go this route you might want to send a sample of the old fluid to JG Lube Services so you know what's actually in there and if there are any wear metals or contaminants in the fluid.

Thanks for your reply Steve.

This coach was bought brand new by my dad. He claims it has this problem (or so we think it`s a problem) since new. I plan on doing the fluid and filters this winter. The fluid to my knowledge is Dexron III. I did talk to the mechanic that did work for dad on this coach in the past and he echoed the same thoughts as we do. He felt that something was wrong with the sync between the engine and transmission. He did state that its normal for Cummins to say everything is fine and Allison to say everything is fine when in fact they have no clue on how one works with the other. This forum has been a great network for me in getting this beast straightened out and I am getting there. This problem was down the list a little way but now its time to look at it. I just returned home from Fort Myers and really noticed this strange shifting in the mountains. It would shift to a higher gear way to soon and then downshift and then upshift immediately. Just weird for a unit with good power that if the shift was made at the proper time would feel and perform much better.

joe

joeplazek · 12-18-2013, 12:59 PM

Quote:

Originally Posted by palehorse89

Hi Joe, look and read page #32 here http://www.rvtechlibrary.com/transmi..._operators.pdf and read on "adaptive shifting". I once read on here instead of going through the sequence on page #32 disconnecting the battery terminals for 2 days or so will clear the shifting program in the TCM that it has learned. Maybe a reset of the TCM will help you with this, and maybe Steve can enlighten you a little more on what I have posted. What Steve posted would be a starting point.... filters & fluid.

Thanks for the reply.

I will have a look at the link tonight when I can read through it. Sounds like something very easy to try. Right now I am open to trying anything that may cure it. Its not really a huge problem but to me it just does not seem right.

joe

Steve Ownby · 12-18-2013, 01:41 PM

Quote:

Originally Posted by joeplazek

Thanks for your reply Steve. This coach was bought brand new by my dad. He claims it has this problem (or so we think it`s a problem) since new. I plan on doing the fluid and filters this winter. The fluid to my knowledge is Dexron III. I did talk to the mechanic that did work for dad on this coach in the past and he echoed the same thoughts as we do. He felt that something was wrong with the sync between the engine and transmission. He did state that its normal for Cummins to say everything is fine and Allison to say everything is fine when in fact they have no clue on how one works with the other. This forum has been a great network for me in getting this beast straightened out and I am getting there. This problem was down the list a little way but now its time to look at it. I just returned home from Fort Myers and really noticed this strange shifting in the mountains. It would shift to a higher gear way to soon and then downshift and then upshift immediately. Just weird for a unit with good power that if the shift was made at the proper time would feel and perform much better. joe

Hey Joe,

Palehorse89 makes a good point. The Allison's do have adaptive logic and that's the quickest and easiest thing to accomplish. Be aware that using the battery disconnect switch on the coach will likely not remove power from the transmission. It will be necessary to disconnect the battery cable. Usually the power to the engine and transmission control modules are not wired through the switch. It will take a few start/stop cycles and a trip or two for the shifting patterns to stabilize.

The fluid/filter should be changed next as I'm sure service is due. The change schedule for DEXIII is annual on both fluid and filters. DEXIII is no longer licensed by GM so the standards are no longer being policed by anyone. Change to a fluid meeting TES389 or TES295. The TES295 is full synthetic and carries a 36 months for filters and 48 months for fluid. Longer on the fluid if tested.

If the above have no effect on the shifting issue then I would go to an Allison distributor not just an authorized dealer. Your Cummins M11 plus and Allison 4060 have first generation electronic controls. I had a very good experience with the Cummins dealer in Fort Myers. I would expect they will chase a problem as far as they can. Don't know the Allison folks.

Good luck with it and let us know how it turns out. I have your same engine/transmission combo just in a later form. I can assure you that when they are working right it's a joy to drive.