No speedo or shift 1994 k2500

[Obsloverrrrr]

Hey y’all, just got a truck.
K2500
It WASNT shifting past 1st, so I replaced the VSS. Still didn’t shift past. Then I took it on a dirt road, put it in 4x4, then took it out. Got back on the main strip, bam, working again! I shut truck off, go to drive it again, bam, no gears. No speedo.
could it be a bad sensor brand new?
I was thinking VSSB... however if that was bad wouldn’t it not work at all? It still turned on for a good 10 miles before shutoff
Could it be the Ignition module or switch? I know that controls a lot.
What should I do next?

 

[Schurkey]

WHAT YEAR? WHAT TRANSMISSION?

When I had a speedo problem, I replaced the VSS and it made zero difference. I replaced the speedo in the dash, made zero difference. Turns out I had a fault in the instrument cluster circuit board.

If I had that problem, I'd be reading the service manual's description of the VSS and how that interacts with the transmission shifting via the wire harness and ECM.

 

[Busted Knuckle]

Hey y’all, just got a truck.
K2500
It WASNT shifting past 1st, so I replaced the VSS. Still didn’t shift past. Then I took it on a dirt road, put it in 4x4, then took it out. Got back on the main strip, bam, working again! I shut truck off, go to drive it again, bam, no gears. No speedo.
could it be a bad sensor brand new?
I was thinking VSSB... however if that was bad wouldn’t it not work at all? It still turned on for a good 10 miles before shutoff
Could it be the Ignition module or switch? I know that controls a lot.
What should I do next?

The fact that it worked would rule out the VSSB and the connection to the ECM. I'm going to guess its an intermittent harness or connector. Make a good inspection of the wiring you can see. I've got a '95 K2500 and have been replacing connectors all over the place.

 

[thegawd]

I dont know these early trucks but when that happened with my 97 it was actually the ignition switch. Lots of troubleshooting got me nowhere. Intermittent electrical issues are the worst. However on a 4l60e, there is only 1 positive connection, a pink wire, it runs from the big main plug under the dash, to the ignition switch then to the fuse in the end of the dash then off to the transmission. All the other wires are grounds that are on or off dictated by the ecm/tcm according to vehicle speed and the throttle position sensor. So if the ignition switch has a failure, the fuse blows or you have a wiring problem the tranny goes into limp mode. You get stuck in 3rd, have no speedo or prndl lights and get like 6-7 tranny codes. Of course the early 4l60es were slightly different than mine in the 97 and it may actually be slightly different but very similar. Pin E on the big round plug at the tranny should read the exact same voltage as the battery, any variance whatsoever and you have a problem, most likely with the ignition switch, a mechanical failure of a very basic switch.

I hope you get it figured out easily and quickly. It took me 2 years to resolve my issue.

Al

 

[98chevy2500SS]

I dont know these early trucks but when that happened with my 97 it was actually the ignition switch. Lots of troubleshooting got me nowhere. Intermittent electrical issues are the worst. However on a 4l60e, there is only 1 positive connection, it runs from the big main plug under the dash, to the ignition switch then to the fuse in the end of the dash then off to the transmission. All the other wires are grounds that are on or off dictated by the ecm/tcm according to vehicle speed and the throttle position sensor. So if the ignition switch has a failure, the fuse blows or you have a wiring problem the tranny goes into limp mode. You get stuck in 3rd, have no speedo or prndl lights and get like 6-7 tranny codes. Of course the early 4l60es were slightly different than mine in the 97 and it may actually be slightly different but very similar. Pin E on the big round plug at the tranny should read the exact same voltage as the battery, any variance whatsoever and you have a problem, most likely with the ignition switch, a mechanical failure of a very basic switch.

I hope you get it figured out easily and quickly. It took me 2 years to resolve my issue.

Al

I had that same issue on my 97 last summer. No gear indicator lights, stuck in 3rd gear, and no tach and speedo. Replaced the ignition switch harness and that solved the issue.

 

[thegawd]

I just noticed where you said it wouldnt shift past first and that it's a 2500.... so it shouldn't be a 4l60e and be a 4l80e instead, that will have a different limp mode than the 60e.... and are you sure it was first?

Anyways, taker easy.

Al

 

[Busted Knuckle]

I just noticed where you said it wouldnt shift past first and that it's a 2500.... so it shouldn't be a 4l60e and be a 4l80e instead, that will have a different limp mode than the 60e.... and are you sure it was first?

Anyways, taker easy.

Al

They all should be limping in 2nd gear.