I have a 93 Chevy Blazer 4.3 vortec engine. I started having a problem shifting a year ago. I have changed all solenoids, wiring harness inside case, filter, pan gasket and of course fluid. Only saw very little metal inside pan when I opened it. Changing the fluid is what originally caused a no shifting problem. Before I changed the fluid it was shifting hard into second, third and fourth gears. When I first change the fluid it was shifting fine then would not shift out of first at all. It seems to me like the people that had the vehicle before me didn't do anything to it at all except what was absolutely needed to keep it moving.

This vehicle is technically my mom's, I asked her about the speedometer and she said that she had been having problems with the display sometimes not coming on and then after a while she was having problems with it reading the right speed. She would have the cruise control on and all of a sudden the speed would be jumping around even though she wasn't adjusting her speed. I really hope that it's an easy fix for this transmission. Please get back to me ASAP. Thank you so much.

A guy on a different forum told me this: The speedo must work in order for the trans to shift the pcm needs that data, Sounds like she does not have a trans issue at all but and electrical issue.

One of my friends told me this: its got a 4L60E then it won't shift without a VSS signal, could be the speed sensor in the transmission, the wiring, or the ECU (check/change parts in that order)
Use a meter or scope to check for an AC voltage from the VSS, if its good then trace the harness, if its got a VSS signal all the way at the ECU then its probably a bad buffer in the ECU. Its probably a bad VSS or pinched wire

Thank you so much ahead of time.

Have you checked for codes?

It sounds like it's a simple VSS problem. They can be high wear items. Start by cleaning the connector. Odds are that it will need to be replaced--super simple. When they go, all sorts of codes can be thrown (PCM and ABS) and dash boards can light up like Christmas trees. Replace the sensor and clear all codes. I've seen trucks where the VSS fails on the road and they can barely hobble home. The information the other guys gave you is correct. I'm virtually certain this is your problem.

Do perhaps know, when checking for codes on this one, if it's a simple as checking for codes on Honda's? Jumpering a couple wires and counting the flashes or do I need to hook it up to a computer?

Knowing GM it's probably not that simple.

Thank you so much for being so helpful with both the Chevy as well as with my Honda :)

Since it's OBD-I, it will be similar to jumping the Service Check Connector on Hondas. You need to check this out, but I believe you jump Terminals A and B.

Oh OK awesome. Thanks so much :) got my VSS today. $35+tax.

I guess you have not installed it yet.

Lol not yet. Didn't feel like laying on the wet ground while it was raining.