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Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 3359
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
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Rory, SO I have an allison transmission in a 2002 Bluebird

Customer Question

SO I have an allison transmission in a 2002 Bluebird Transit bus. FOr the first time I left a location and placed the unit in reverse, it jerked sort of hard and the shift pad flashed R. I put the unit in drive and had no problem. I drove the unit 2 blocks to the stop sign and when slowing down the shifter pad flash D and would not move. I then put it in N and then back into D and the unit moved along with no problem. I drove the unit back to the office without any problems.
Yesterday the same problem started back. I have noticed that it jumps with flashing D only when I have almost come to a stop. It has never done this while moving with speed. THe unit does not jerk anymore, only flashes D. It goes right back into gear w no problem. The code given was D1 3500. The fluid level checks okay.
Prior to this occurring, I did have the bus at an ac shop being repaired for the bus ac unit.
No previous problems. Worried slightly.. I hope it is a simple fix...
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 1 year ago.

My name is ***** ***** I will assist you with your question today.

I'm an independent contractor and I don't get paid until a rating has been made.

We can go back and forth as needed to help resolve the issue you are having. Follow ups are free after ratings, so rate in confidence!

That is a battery voltage low to ECU code.

I suggest having a shop look at the power lined going to the transmission controller on this. One of them is rubbed through and causing the shift issues to happen. You can operate the bus for now, but if the wire burns all the way through, it will leave you stranded. I suggest setting a down time for the bus for it to be checked out as soon as you can. You don;t want to have a load of passengers and be stranded somewhere.

Before taking it in, check the fuses at the battery box and make sure all the connections are good and tight as well there. If they are all good, then get it to the shop. A loose connection at the batteries can cause this.


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Customer: replied 1 year ago.
Thanks for your expertise on this matter.. I will have a shop to trace the lines. Would this also cause the jerk that I described earlier also. Thanks again for the prompt response.
Expert:  Jeremy replied 1 year ago.

Yes it would. When the voltage is low, it causes jerks, hesitation in shifting, drops right out of gear, even long shifts. I've had them go to neutral and slam into gear while going down the road as well. Picture it like a switch and you have a fan going. If you are flipping that switch off while trying to change the direction of the fan and suddenly you turn the switch on, it binds the fan motor. The transmission electrical is pretty much doing the same. It is acting like you are turning a switch on and off with the power drops. It just needs to be determined what the cause is so the rest of the issues go away.

Expert:  Jeremy replied 1 year ago.

I see you viewed this and this is still showing as an open question due to no positive (3 stars or more) rating.

Were you not pleased with my service to you or is there a rating issue? Please let me know if you still need assistance with this, if there is a rating issue, and/or you need more time to respond.

I like to make sure all my customers are satisfied since you did pay a deposit for me to assist you, whether I’m paid by a positive rating feedback or not.

We can continue where we left off or start over if needed. Also, if you need diagrams, instructions, etc please don’t hesitate to ask.