TheRavensNest

My 4+3 1986 c4 hasn't had a working speedometer the whole time I've owned it (about 10 months). I recently took on the endeavor to fix it. I took out the speed sensor on the back of the transmission to find that the clip holding on the drive gear had fallen off. Put that back on hook it all up again and the speedometer worked great....for 2 min. Put it back up on the lift take the speed senor out and find my drive and driven gears practically melted together. My question is what would cause them to heat up like this and where can I get new ones. It seems the part has been discontinued. The area where the drive gear is gets oil (or whatever that fluid back there is) as both times I took it out fluid came out and the gears were wet but I don't know if it's enough. The part numbers for the gears are GM # 8640517 for the Drive gear and GM # 25513049 for the Driven. Any help on this would be greatly appreciated.

WVZR-1

What color is your VSS? Is the VSS connector in the center? It sounds like possibly the incorrect VSS is in it presently. On the VSS is there a number sequence of 35 - 39 or maybe 40 - 45?

I likely have the drive but don't have the driven. You need RED(17)/GREEN(42) if Greg asks for colors

Greg @ Blower Works likely has both. Contact him. greg@blowerworks.net

You do need the correct VSS though. I don't have any NOS left but might have used. If I have used it works.

Where are you located?

Will your VSS spin on the end of a rotary tool/drill?

TheRavensNest

My VSS spins smoothly and while it was working was 100% accurate. Certainly seems like the right one. I'll try and get a hold of Greg and see what he says. My biggest question is still why did the gears melt, it has my quite confused.

WVZR-1

You didn't answer questions!

I asked: What color is your VSS? Where are you located? Color presently is the more important question to answer!! Is the connector in the 'center' of the VSS?

TheRavensNest

My VSS is silver and the connector is in the center of the sensor. It takes a 2 pin electrical connector. I live in New York.

WVZR-1

The center of your VSS is either 'white' or 'black' with a crimping band around it that's silver. If you were close I was going to offer to look!!

TheRavensNest

Unfortunately it looks like I won't have the time to really fix this right now. I'm moving to Georgia so I can attend college. This will probably have to wait another couple of months before I can fix it but thanks for the help. I would put my car back up on the lift and take out the VSS to check further but I just don't have the time right now.