1993 GMC 1500 4x4 poor shifting

The shifting problem is probably because of the dead speedometer.
Have you checked the fuses in the engine compartment, and the main harness connectors ?

Not good! there is a sensor in your transfer case that senses that you are now in four wheel drive if your transfer case does not lock in it will set a code and the light will flash and default back to two wheel drive. check the fluid level in the transfer case and front differential for a sign of internal failure. that is causing the grinding sound.

YEP YOU NEED VSS SENSOR HOOKED UP SO TRANSMISSION CAN SHIFT RIGHT.AND SHIFT TO OVER DRIVE AT SET SPEED. YES YOU NEED TO SEE YOUR SPEED TO KEEP FROM GETTING A SPEED TICKET.DONT UNPLUG IT.

I really need an answer to this question, also. Mine started doing the exact same thing today.

speed sensor on trans axle will cause this hope this helps don

I am sorry but i know this symptom on this exact transmission and u are going to need an overhaul.

Replace the vehicle speed sensor, it's located in the tailhousing of the transfercase

I have found that when you are going to engauge 4x4 high, it is best to only be going about 3 miles an hour. Not faster, not stopped. It likes some movement to help it mesh. I've had perfect shifts since I started this. Hope it helps. Wade.

Your blazer is equipped with a shift on the fly four wheel drive. That means that at speeds less than fifteen miles per hour you can shift into or out of four wheel drive by simply pushing the four wheel high button. If you wish to shift into four wheel low. Stop, put the transmission into park or neutral, and push the four wheel low button. Same procedure for shifting back out. Never shift into or out of four wheel low while moving. And be careful in four wheel low. At full throttle your still barely moving, you don't want to blow your engine up!

when i bought mine the speedometer odomoter and raido didn't work
put in a fuse that wasnt' in got them all and now when u are driveing it shifts out of gears or sometimes it wont shift past first any ideas?