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don-deb · 10-30-2010, 03:28 PM

We have a 06 Phaeton 35DH with a Cat 350 and a Allison 6 speed. Today we were on our way to enjoy one of the last weekends we will be using the coach until next season. :(

All of a sudden 2 red lights came on the dash.....one says " check tranny " the other says " shift inhibitor ".....The tranny was stuck in 4th gear.....I couldn't shift it or put it in neutral. What is that all about ?

I pulled to a safe area.....shut down....checked the tranny fluid. All was good. Started back and it was back to normal. The rest of the trip was flauless.

Any ideas ????

Thanks

Mike Canter · 10-30-2010, 05:03 PM

Don it may have just been a erronous trouble indication or a warning that something is wrong. I don't know how you checked your fluid level but my guess is using the dipstick. What you should do is to check it with the Allison transmission operator keypad. If the transmission fluid is above 140*F then park it on a real level surface with the motor running, give the transmission 5 minutes for the fluid to settle in the pan then you push both the up and down arrows on the keypad at the same time and it will read the fluid level. After the fluid level it will check for error codes and may tell you if you have a problem or not. This is Allison's prefered way of checking the fluid level.

It should explain all this in the Allison operators manual that came with the MH. If not then you can download a copy here
http://www.allisontransmission.com/s...t=OM3349EN.pdf

don-deb · 10-31-2010, 05:50 AM

Mike.......thanks for the info. I didn't know about the key pad test....interesting. I checked it the old fashion way.......on a flat surface with the dip stick.

The fluid was clean ( just changed when I purchased 5 weeks ago ) and full. I'll do the key pad test today.......when we get ready to break camp. I didn't think it was a total tranny failure.......with only 26,000 miles on the coach................BUT

HD4Mark · 10-31-2010, 06:16 AM

The up down arrow check needs the tranny to be warm. I tried it with ours after a 45 min drive and got an error code. Nervously got out the manual and all it was telling me is that it was not warm enough to check it. The dash gauge stays so low I wasn't sure it worked at first.

Mike Canter · 10-31-2010, 06:43 AM

Thanks Mark, I was just going to tell Don that. It is never going to work after a warmup just in the campground and you will get a code saying it is too cold.

don-deb · 10-31-2010, 08:49 AM

OK........thanks guys. We have about a 2 hour ride home.........I'll give it a check.....using the control pad.... when its home in the driveway.

I'll post my findings.

Thanks again...........

RickO · 10-31-2010, 09:19 AM

If I'm not mistaken, you can also access historic error codes too by pressing both up and down arrows again following your fluid level check. This might give you an idication of why it locked up in the first place. The definition of error codes is in your manual.

Rick

Mike Canter · 10-31-2010, 10:05 AM

Go to page 95 tpo review how to read error codes.
http://www.allisontransmission.com/s...t=OM3349EN.pdf
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wa8yxm · 10-31-2010, 10:59 AM

One thing to consider... The computer that controls the tans is an electronic device with leads.. This means that it can be "Glitched" by a very strong RF field.. NORMAL cb or even Ham radios will not bother it (They test it with like 500 watt transmitters in the vehicle believe it or not)

BUT: A CBer with an ILLEGAL Kilowatt or so can be splattering all over the RF spectrum and can, in fact, find a crack in the electronic armor of most any nearby computer.

don-deb · 10-31-2010, 12:44 PM

OK.......just got back home........it happen again 2X on the way home. I noticed it happens when Im on a winding ...narrow....up/down hilly road. I had to stop....shut the engine down wait a minute.....then fire back up....then the lights where gone......and it shifted fine.

I did the 2 arrow test on the contol pad......it read.... " 95 " then " --- ". It did that until I put it back in drive.

The thing that confuses me is once on the expressway.......and doing 55/60 mph.....NO lights.....NO problems. This leads me to ASSUME the fluid level is fine ?????

Would the exhaust brake have any effect on the problem ???

Thanks guys........

Mike Canter · 10-31-2010, 01:22 PM

Hmmm a 95 code means a sensor failure for the fluid level. See page 62.

The big thing is did you hit the up and down arrows the second time to read fault codes? You can do that without the transmission being at operating temps. Read page 95 especially where is talks about reading the codes and the MODE LED to tell you if it is active or a code in history. This test it what is going to tell you more.

Yes the exhaust brake can cause a problem because the transmission is re-programed for the exhaust brake and there is a wire that goes from the exhaust brake to the transmission so it knows to start downshifting when the exhaust brake comes on. Also that fluid level sensor can be the problem.

You should get a four number fault code if you press both arrows twice, Onece you get a fualt code then write it down and press the MODE button to step to the next fault code. Keep writing them down and presssing the MODE button until you get them all.The codes are listed starting on page 102.

don-deb · 10-31-2010, 01:54 PM

OK.....Mike.......I'll give that a try tomorrow morning..........see what I get for fault codes.

Thanks

Midniteoyl · 10-31-2010, 06:05 PM

I betting on a loose/dirty connection at the tranny....

don-deb · 11-19-2010, 09:56 AM

Well........I finally got time today to get our coach over to a local authorized Allison tranny shop.

The tech brought up code " d721 " using the key pad. Then plugged in his computer into the service port under the dash......to verify the code.....it was "d721 ". He checks the shop manual .....says its the speed sensor.......tells me it will take about 20 minutes to change.......20 minutes later....DONE. We take it for a road test for about 1/2 hour......... problem solved.

Now we have one more trip planned before we pack her away for the winter.........