any updates or progress?

Well he made it home safe, late last night. I'll be taking it down to the shop tomorrow.

let us know what the issue was please....glad to hear he made it home

i own a dodge so i don't know how different our situations may be, but i had basically the same thing happen to me before. i pulled onto the interstate and the truck would not get over 45. no lack of power or anything, just would not shift into fourth. it all wound down to a bad ground on one of the batteries sending a messed up electrical charge to the computer. the speedometer really confuses me though.
good luck with it n let us know what ya figure out

40 MPH
 

Is this a 4X4? it sound like stuck in 4WD!!
wrench

Well I wasn't able to pick up the truck until Friday evening, and of course the shop isn't open on the weekends, so the truck will be sitting here until Monday.

I did talk to the guy at the repair shop and he told me to check the VSS (Vehicle Speed Sensor) for debris or loose / cut wiring. I know it's toward the rear of the truck, but I don't know what I'm looking for. Does anyone know where I could find this on my 2004 Chevy c4500?

I'd like to at least check it before I take it in the shop tomorrow morning. Thanks.

PS. The battery wiring seems to be squared away, and no it is not a 4x4.

Im curious what is wrong. Please post up what they find out.

yes filter can get plugged with 5 miles. is it 4 wheel drive maybe he hit 4low by accident if nothing else is wrong

i think that he said at least 2 times that it is NOT 4x4

Well the truck is in the shop. The mechanic called me and said he changed out the VSS (Vehicle Speed Sensor) and it still isn't working right. He can't find anything else wrong and there are no codes at all.

He says that he thinks the ECM is a bit haywire and reading the wrong speed and recommends getting the ECM reflashed. They can't do it there, and the local dealership can't work on these trucks, so my only option right now is to drive 170 miles (at 40 mph) to the nearest dealership that can reflash the ECM.

And he said that he isn't 100% sure it will fix the problem, but it's the only other thing he can think of. I'm having him change the fuel filter while it is there as a longshot, but it looks like I'll be heading out on a short, slow trip. Of course, if the reflash doesn't fix it, it's going to be a long trip home too. :s:

I'll post back with another update once I know more. Maybe it will help someone out in the future. Oh and thanks for all the replies and help guys. :tu: