its old
the speedometer wont work and quite likely the automatic transmission fluid or oil (manual trans) would leak out and the transmission would be ruined.
because your car is broken
wish i knew have the same prob on my 93 377 peterbilt
It wont start
Speedometer can determine a car's normal and maximum speed.
Check for a blown fuse.
get a new one
Check VSS or wiring to it could cause fault .does speedometer work?
you replaced speedo, so try replacing speed sensor
Speed sensor. There is not a cable on this car.
well that's not to hard to answer. my truck did the same thing i replace the speedometer cable and sensor in the transmission and i never had that problem since. try that first and see what happens if that wont work then replace the speedometer panel in the dashboard.