Transmission Shift problem

[aggies09]

I had some warranty items taken care of at Prevost Ft. Worth this past week and commenced to driving the 185 miles home. Everything was working flawlessly until I slowed down to take the loop around Abilene towards home. At this point the transmission (world) would not shift beyond 4th gear. I limped on home from that point. First thought was transmission fluid. Full.......After sitting for about an hour and cooling down, I jumped back in and drove down the road and it operated perfectly.

Any thoughts as to what may have caused this and what I should do about it?

[Jon Wehrenberg]

I'm no transmission expert, but I do know that an Allison dealer can connect your tranmission via the internet to a computer that can give you a report. It has enough detail to even show the amount of wear on the clutches.

[garyde]

Hi Tony. Did you look at the oil to see if there was coolant contamination. If you have a Allison directory, you can also check the codes. Try Allisons website also for trouble shooting tips. http://www.allisontransmission.com/

[hhoppe]

Tony: I had that happen to my Royale. It was the shifter keyboard. The brains are under the shifter buttons. Mine got wet and required a rebuild on the unit. I was lucky to find a repair shop and did not have to buy a new one $$$$$. Some times while gearing down you hit the wrong button, like neutral or reverse. It fakes out the computer and it needs a time out to get back on track. Also do not spray water through the window crack onto the shifter keyboard. Now mine gets a towel over it when I'm washing the bus.

[merle&louise]

Tony,

A similar thing happened to me at the Sevierville rally. I was playing with the mode button and the tranny jumped into neutral. The solution was to turn off the engine, wait a minute or so, and then restart (re-boot the transmission computer) the engine.

After that incident, I began having trouble with the shift pad, when I would press the buttons it would not respond. Through trial and error I determined that I had to press the center of the button and not the outer edge. Everyting is fine now. The point is the transmissions can be a little finicky. I would just have it checked out at your local Allison dealer.

Love your bus, the colors are beautiful. I hope to see it one day at a rally and meet you and your wife.

[JIM CHALOUPKA]

Tony, looking over manuals that came to me with the Bling Mobile, I read about how one can pull up any fault codes of the transmission through the shifter pad of the bus. I don't remember exactly how to do it and the bus is now 100mi away, but maybe someone else can instruct you. It was easy though and something like pushing two finger pads at the same time, waiting a little and then counting the flashing light for a two digit number that is then cross referenced to a fault list. There is an extremely long list of faults so it is possible that your problem is listed.

:) JIM

[rfoster]

Once upon a time I had speed sensor replaced on a 97 Liberty coach because of a inconsistent shift pattern. Shifted hard from 3rd to 4th - cost about 100 bucks installed-- It was diagnosed by the local Allison dealer with his lap top.

About a year later the problem returned, I did nothing more than jiggle the wires and check the connection to make sure they were secure and it fixed it again. The speed sensor on that tranny is located on the drivers side on the side of the tranny housing.

another two cents.

[aggies09]

Thanks for all of the input, I am going to try to get it to display any error codes for me and go from there. You guys are a great help for us newbies.

Much thanks to the exiled AIG/government employee as well. The call gave me some much needed direction.

[merle&louise]

Tony,

The way to have the shifter pad display the codes is simple. Press the up and down arrow keys similtaneously with the engine running and in neutral. It will go thru it's sequence and error codes will be displayed after it checks your oil level. When it is finished checking oil level it will display: O L O K
Then if you have any codes they will display.:)

[aggies09]

Tuga,

Thanks for that. Saved me a half hour of reading to find that.

[rbeecher]

Hi Tuga,

Does the tranny need to be at normal operating temp for the code test? Trying to remember...

Richard Beecher
02 Marathon XLII 45
96 VOGUE XL 40 For Sale

[merle&louise]

Richard,

Yes I think it does have to be at operating temperature (180 degrees)and level for the correct oil level reading. However, I would assume that the codes would be displayed regardless of whether or not the engine is at operating temp.

[aggies09]

Getting the codes was a very easy task. It does not have to be at operating temperature. I displayed two codes that indicates an "open circuit" and an excessive temperature. I am trying to get into an Allison service center later this week to have it checked out. I will keep the group posted in case anyone else experiences same.

[merle&louise]

Tony,

Is your transmission temperature gauge showing higher than 210 degrees?

That is the limit where the thermostat is supposed to open. I thought mine was overheating, but Allison told me that as long as it stays under 210 it is o.k.

Hope it is something simple to fix like a bad sensor.

[JIM CHALOUPKA]

Tony, how many miles are showing on your odometer.

I hope your alarm is a sensor problem, as the other thing that can cause excessive heat is slippage, and that means clutches or pump pressure.

Good Luck, JIM

[Jon Wehrenberg]

210 degrees is not the transmission limit. The temperature is sensed at the retarder output, the hottest possible temperatures will occur here.

If I am not mistaken the transmission computer will reduce the effectiveness of the retarder to keep temperatures below 300 degrees. As drivers we should work to keep the temps down anyway because high temps are not good for the fluid. My guess is a sensor is reading temps incorrectly.

[phorner]

Transmission temps of 200 degrees or so don't seem that out of the ordinary to me. Ours runs typically at 205 to 215 depending on ambient air temperature, grades and use of the retarder.

An occasional, almost momentary, reading of 220 or 225 was also not that unusual, with 225 being about the maximum that we experienced.

[aggies09]

Tuga: I have never seen my gauge heat up above 205. It typically reads right at 200.

Jim: I forgot the exact mileage, but it is about 82,500.

My initial conversation with Allison indicated several things to check upstream and if nothing was evident there the reservoir would have to be opened up and there are a couple of sensors there that need to be inspected. It looks like it is going to be next week before I can get into the shop. Holidays and vacations.