1999 Suburban 4x4 Speedometer Problems...

[ABeal85]

Hello Im new to this forum and i have a problem thats got me stumped so i hope you all can help me out.

1999 Chevy Suburban 1/2 ton 4X4:
My speedometer quit working on me. Here is a list of things that i have changed and or replaced:
Transfer case Rebuilt
Transmission Rebuilt
both Speed Sensors replaced
Neutral safety switch replaced
i have checked and checked again to make sure everything was plugged back in, and im stumped. My Tachometer works just fine. When i start my truck and put it into drive it shifts from 1st to 2nd and wont shift into 3rd at all. so i have to manually shift if from 1st to 2nd from there on out...

 

[zora]

Copied this from another site:
Check with an ohm meter for an open wire between the vcm and the sensor on the transfercase. Check at the pins 29 and 30 in C1 at the vcm. With the vcm disconnected and the vss connected, you should have continuity between the pins and No continuity to ground. If you have continuity to ground, you've got a pinched or chaffed wire somewhere. It may have been damaged when you did the rebuilds..