If my trans was unplugged will the speedometer quit working and trans quit shifting? 04 chevy 5.3 z71 vortech

https://www.youtube.com/watch?v=S3mE2sORykY
https://repairpal.com/why-does-my-speedometer-jump-when-im-idling-403
https://www.duramaxforum.com/forum/04-5-05-lly-duramax-powertrain/79631-not-shifting-service-brake-system-abs-speedometer.html

speed sensor / speedometer drops too zero - Car Forums and ...

www.automotiveforums.com > ... > Ford > Escort

Because the speed sensor isn't working the speedometer isn't working either. ...thinks you are stopped or going very slow and won't shift it out of first gear.

Won't Shift Out of First - BIONICDODGE.COM

www.bionicdodge.com/bionic/index.php?topic=1645.0;wap2

A friend of mine has a Durango, the tranny wont shift out of 1st. ... Tip: If its a speed sensor problem, you may find that the speedo isn't working very well. ... To check and see if 2nd gear is messed up mechanically, manually hold it in low 1, ...

21298304 Tack and speedometer quit working, won't shift ...

dochost.no-ip.org/F/.../t21298304-tack_speedometer_quit_working_shif...

My van won't shift into overdrive, speedometer isn't working, door locks are not ...My speedometer quit workin and my gears are a lil hard shiftin and i have no ...

Speedometer Odometer trans shift issue - Ford Truck Enthusiasts Forums

www.ford-trucks.com > ... > Misc. > Electrical Systems/Wiring

sounds like the vehicle speed sensor. its located in the trans. there might be two. this controls the speedo and shift

first get a trans flush and fill if it keeps doing it then it is time for a new trans because the band are slipping in it and shift module is going out

Your car reads off of the trans. Sensors to shift. You are going to need an input and output sensor, that will fix your speedometer also.

Hi,
Likely one of your Speed Sensors (VSS) is bad. Sorry I don't know WHERE these are located, but get on some of the Chevy Truck forums for answers.

GL,
TD

could be the VSS - vehicle speed sensor .
Speedometer and Odometer
The Vehicle Speed Sensor (VSS) is a gear driven permanent magnet generator. The vehicle transaxle houses the VSS. The VSS generates a sine wave output with a frequency proportional to the vehicle speed.
The Powertrain Control Module (PCM) converts the CKT 389 signal to an output that switches to ground at a frequency of 4000 pulses per mile. The CKT 389 signal drives the speedometer and the odometer. Various other vehicle components use the CKT 389 signal. Refer to Engine Controls.

It appears to me that you didn't plug in the wiring harness into the transmission. If you did, then you probably forgot to unplug it when you pulled the trans. and broke some of the lines. The abs is probably not related.
The trans in your truck shifts electronically, if it isn't plugged in or if the harness is damaged, it will not know when to shift. It is computer controlled.

possible speed sensor at rear of transmission,does engine rpm sound higher then narmal,and is your trans shifting as it should,if these problems are also present replace the speedometer sensor at rear of trans,$50 to 60 bucks