Author Topic: Allison Trans Loss of Gears 1 thru 4. Code 5-4-5-4 "On Coming Ratio Test"  (Read 8436 times)

Paul Sharps

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2004 Patriot Thunder, C-12, Tag Axel

When beginning a descent on an approx. 5% grade, I noticed that the Jake brake was not functioning. After pulling into a turnout to check the situation, I noticed that the push-button shift selector displayed  "5". This seemed unusual since I would normally see "6" given that it was in the "D" (Drive) mode. When I pressed the "D" button, "5" remained on the display and there was no forward motion from the transmission. When the "N" button was selected, "N" was displayed. Next I selected the "R" button and "R" was displayed as expected and engaged the transmission. Next the "D" button was selected and the display changed to "6" as expected but there was still no forward motion by the transmission. After several attempts there was no forward motion regardless of the gear selected. However it would consistently engage the reverse gear. The “Check Transmission” light was never displayed during this time. All fluids and batteries were good. Temperatures were in the normal range.

After the coach was towed to a service facility two diagnostic codes were found: 2-5-1-1 “Output Speed Sensor” and 5-4-5-4 “Oncoming Ratio Test”. I was told that the 5-4-5-4 code was the most problematic of the 2 codes. A tech from an Allison Dealer was called in for further analysis. He concluded that the fault was low pressure in a section of the transmission that engaged gears 1 thru 4. He recommended that the transmission be removed for repair of the problem section of the transmission and that a rebuild would not be necessary. However when the service manager was contacted to schedule the repairs, the story changed. He said that the best solution would be to install a rebuilt transmission (around $9k).

We drove a little over 10k miles this past year and the coach performed flawlessly – no indication of any transmission issues until the above incident occurred. It seems that a rebuilt unit would not be required with only 64,000 miles of service.

Has anyone had an experience that could offer a perspective on this situation?
« Last Edit: June 30, 2015, 07:48:39 PM by Glenda Farris Co-Admin »

Steve Huber Co-Admin

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Paul,
A few years ago my transmission acted up. After stopping for a stop sign, the coach would not shift out of 3rd. (I don't remember the codes it flashed).  Had the unit towed about 100 miles to Interstate Power Systems in Minneapolis. After running a number of diagnostics they determined the problem was with one of the clutches that would require major work to get at. The tech working on it then suggested we take it out for another test drive. We did and it shifted perfectly. He smiled and noted that the electrical connections to the transmission can be problematic and he had been moving them around in running the diagnostics. 2 hours later we were on the road again with new connectors on the electrical cable(s) to the transmission. It's been working fine ever since.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Dave Atherton

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Paul, I would suggest getting a second digonostic on your problem. In most cases it is wiring issues
connections, or connector. Your looking. ( Price $ 9,000.00 or more ) and sounds like between tech
and shop manger difference of thoughts, which throws out a flag simple repair or major repair in
most cases boss wins. The Allison transmission is a very trouble free transmission and major repairs
rare. The electronic's , connector, broken wire etc.  Allison has very good support people and taking
a little more time to settle thoughts you may find second opinion will back up simple problem and
not major repair.  Dave Atherton Retired Cat Mechanic

Paul Sharps

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Dave, thanks for your perspective on this. I am rapidly coming to your suggestion for a second opinion

Keith Duner

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To add to David's great advice, I would always recommend going to an authorized Allison distributor over an Allison dealer if one is close by.  Check the Allison web site service locator.  Just stands to reason that distributors will typically have more experience on the products than a dealer might have (of course there are always exceptions....).

Edward Buker

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Paul,

Is your transmission set to go to 5th with the Jake on? If so it may be that 5th display was just the result of that engagement. I was wondering if you have tried just to disconnect all of the battery + cables to the house and chassis feeds to the coach and wait 15 minutes and then reconnect. There is such a thing as stuck logic in the computers used to run the engine and transmission. It does seem strange that this happened with the engagement of the Jake. The intent here is to see if everything by powering down can be reset. I have no doubt that they got an error code but the question is cause and affect. Did the computer get hung up and cause the fail that produced the error code or was there a real failure in the transmission that provided the error code. This does seem rather sudden and suspicious. Most things are worth a try before you dig deep and spend that kind of money.

Later Ed
« Last Edit: June 27, 2015, 12:13:19 AM by Edward Buker »

Paul Sharps

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Ed - thanks for your response. Your comment about the Jake being set to gear 5 makes a good point. Yes, it does go to Gear 5. However, there was no resistance from the Jake brake which is what prompted me to pull over. However, you may be correct about why gear 5 was displaying on the selector. I would like to try your suggestion about disconnecting the 12v power supply. It can't see any down side in doing that. The coach is about 100 miles away at a repair facility. I will call the service manger in the morning and discuss with him. Will let you know the outcome. I am having the annual service done while we sort out the transmission situation.

Paul

Doug Allman

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2004 Marquis C-12 Allison 4000 6 speed.  We purchased used at 32000 miles.  At 38000 miles it locked in 5th gear. We could drive it but it would not shift down to lower gears.
Allison distributor reprogrammed, checked all connections and still locks in 5th gear.

Removed and opened unit. The O ring, which is about 12" in diameter, looked like it had been chewed on by mice all around.
Short of it is this unit had been out for repairs twice in 32000 miles and the Allison shop which performed repairs did not get the O ring in correctly. $4500.00 later we had a shifting transmission. At 74,000 miles now and doing real well in mountains and flat terrain.

Make sure you get an Allison shop that actually does rebuilds on a weekly basis. This is critical to the performance rather than using a "trained certified" shop.