Hey guys, so for the past couple drives, I've noticed that when it shifts from 2nd to 3rd, there is an extra long rev up inbetween the gears, then when it hits 3rd it's kind of a hard shift. None of the other gears have an issue... On my way home today, the "DO NOT SHIFT" light came on, and it was stuck in 4th. I wasn't far from home so I took it all the way to the house in 4th. It would not go to neutral so I cut the motor off. I then started it back up, and it went back to neutral, and I able to take it down the street again. This time it did not get stuck in 4th, but it still did the hard 3rd shift. Someone told me one time they experienced something like this and it was a speed sensor... Any suggestions?
I doubt this has anything to do with my alternator/ground problem, but I had a shop looking at that today. My battery light and my battery Hi/Lo light is on. Could this at all be related?
Thanks for your help. I plan on getting it to an actual coach shop on Monday.
I can't remember, do you have the ATEC 748?
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FLash the codes on the shift pad it will tell you, this not related to your problem but I went on a call on a bus than was in the limp mode because the driver forgot to fill it with DEF the electronic gods are out to get us ???
Hold the mode button down for 15 seconds it should clear the "limp" you will hear a beep or the limp will go away if you shift to neutral or supposed too.
What mode are you running in when you get the longer and hard shifts Economy or Performance,they are supposed to go back to the Economy mode on a restart
How do flash the codes?
Not sure if I have the ATEC 748
A 1996 Prevost will have a World Transmission
I know it's an Allison
So I should have the motor running and it neutral to flash the codes? Or have the motor off?
Forgive me, I don't know what "limp" means.
I assume economy because I have never changed it
Just to clarify, after I turned the motor off and back on, it reset and is shifting again, but before starting the motor, the do not shift light is on, then turns off when I start it.
Quote from: Bryan on July 22, 2016, 04:10:42 PM
I know it's an Allison
LOL and a expensive Allison to repair,have you checked the fluid level you do that with pad,down load a manual they are free and do some serious reading then you will know the tricks and trade of the B500 Allison,I still say you should have the fluids changed so you know what you have.They lock in gear when one goes into the "limp" mode
Ok thank you. Yea I had the fluids changed about 2 months ago, About 4,000 miles ago. I had them use Transend.
Low voltage to the ATEC will really screw with the tranny. FWIW
I like my mechanical V730 and HT740.
Bryan,When you had the fluid changed did you have it done at a certified Allison repair center ? The reason I am asking there is a certain way that the filter has to come out and if the procedure is not followed correctly it will cause the symptoms you describe.By the way,it is not unusual for the DNS light to come on when you first start the bus.