Allison Shifting and Speedometer

[briansteinkerchner]

I have a 1995 Patriot with Cummins 8.3 and Allison transmission.  Some times when I try to shift into gear the key pad will just begin flashing and make an alarm noise and will not go into gear.  To get past this I need to shut down the engine and shift into gear as soon as I start the engine.  I also have a problem that when the unit has been parked the speedometer will indicate speed while parked.  As I rev up the engine the speed will go up.  This seems to go away as the unit warms up.  Not sure if the two problems are related.  I replaced the original VDO speedometer with a new VDO speedometer and the problem is about the same.  I can live with the speedometer problem but the shifting problem worries me.  Any help or ideas would be appreciated.  I bought the coach about a year ago and have been fixing it up.  I really like it and enjoy fixing things, but I cannot figure this out.

[Gerald Farris]

It sounds like you are going to have to get a good shop involved in your problem, and yes they may be related. If the transmission computer sees excess vehicle speed or excessive RPMs, it will not allow you to shift gears and the it will just flash the key pad and sound an alarm. So if the transmission computer is seeing the same signal that your speedometer is, it is doing what it is programed to do. Therefore, you will need to tie into the data link to determine what is going on, and that will require a shop with the ability to read the data stream.

Gerald 

[briansteinkerchner]

Thanks for the input.  I was afraid that might be the case, but was hoping for something simple that I could work through.