I have a 2004 Silverado 2500HD with the Allison transmission.Recently I get a message on the dash when I shift from park to reverse or drive. Itsays Range Shift Inhibited. I looked at the manual and it just says put it back in park or nuetral and try again. I called a local transmission company who is highly regarded and they have never heard of this. I called 2 Chevy dealers and neither one of them have heard of this. Does anyone know what this is?

 

Looks like your gonna need a new one from what I have found, but it should be covered under warranty.

http://www.gm-trucks.com/forums/inde...t=#entry158361

 

I have that same tranny and after two days that I bought the truck I had to return in to the dealer to replace something in the tranny. I don't know if this is related but maybe it could help.

 

I have finally been told by the third dealer I called that it is clusters. They told me this is a known problem.. Why nota recall? It sucks that you have to get stuck someplace and find this out.

 

this is 4wd?...clusters can do this,but a re-program of the cluster would fix it,as its a software issue IF its the cluster

it could begetting a bad speed sensor reading and prohibiting a shift,but there should be some trouble codes in the TCM

any other symptoms at all?..or just the message?

if it is a cluster,a re-program may nail it/ ..gm is buying some 03-04 clusters,...how many miles on this?

 

Nice Avatar Argon!!!!!!!!LOL

 

Once moving everything is OK. When you get the message of course nothing happens. The other day I had it 2-3 times before I could move. It is 4 wheel drive with a bullydog downloader installed. I have taken it back to stock, but same issue.

 

Forgot 53k miles

 

Got it fixed today. It was the ignition switch. Seems the voltage was everywhere and it controls the shift. The tech said this is the first time he ever saw this.

 

I have the same magnaflow too and love it, you can usually get a used one on ebay or cragislist. I wanted a valid warranty so I got it here. Magnaflow 2173. Also some of the forum sponsors usually have a sale going on. Either way its a great exhaust system, sounds great, and very easy to install.