Well.... picked up my Bonnie from the shop.... $1117. He replaced the VSS.... at least it'* on the bill. Said he test drove it.... apparently not far enough. After the temp reached a steady 180 degrees, for about 10 minutes, the incredible bouncing speedometer started.... got worse and worse over the next few miles, just as before. Eventually, it drops all the way to zero, then catches and zooms back up. When it drops to zero, the tranny completely slips. No other guages bounce or move in any weird fashion at all.... just the speedometer. There is no ALT light on, nor does the CEL come one. The mechanic said it didn't code anything.

The only new thing I noticed, was the fact that the speedometer seemed to begin to drop as the tranny shifted up or down, and would catch and zoom back when it shifted again...... in other words, the "bounce" roughly corresponded with the shifting..... until it completely drops to zero, then the tranny slips.......

I pulled the VSS to see if it looked new. It does. The bracket that holds it down was shinny brass.... not dirty like everything else. The wires leading to it looked okay, but the black plastic, ridged wire cover / insulation was dry rotted and hanging down. I tried to see if the wires were laying on the exhaust or something similar like that... it doesn't start acting up till it gets good and warm. She'* fine when she'* cold..... Maybe the wires are getting hot? Also.... I was wondering if there was a way to test the VSS while out of the car......
And of course, the $1117 question is: If the VSS is okay... what would be next thing to check be?

Thanks, Guys.....
--Mike

Check the connector leading into your trans for proper connection. Should be right underneathe the air intake.

Are you talking about the connector to the VSS itself? It was clean and tight when I removed the VSS. The wires enter a wiring harness almost at the VSS, so I don't know that I can even follow it from there.....

Mike

Nope, this one right here. Circled in yellow.

Okay... I did in fact find that and pulled the connector off. The Connector itself, at the end of the wires, was clean and dry... looked fine. The plastic ring, into which is snaps, is not tight, but wasn't dirty or corroded inside. I could wiggle it a little in the transmission. Didn't know if it was supposed to pull out or what, so I didn't mess with it.... just plugged the wires and connector back into it.

What is it, by the way? Anything that would cause the symtoms I'm having? Should I go ahead and take another test drive, now that I've messed with it?

Ok, what was it exactly the shop had done when they had it? Other than the VSS. The computer looks at the VSS to determine what gear the transmission needs to be in. Thus the reason for the electrical connector on the trans. Either something is wrong with your wiring for your VSS, or you are having differential problems. Watch for a PM.

Well... other than the VSS, they did nothing that was tranny / electrical related. Fixed a leaking Gas filler tube, fixed a leaky radiator hose, replace all the idler pulleys, replaced the supercharger belt, put something in the power steering pump to quiet it down, which didn't work and replaced the AC compressor and dryer and flushed that system.

What are the odds that the VSS he got is defective? Is there a way to test it? From the explanations of the Tranny / VSS relationship, it seems like the perfect culprit. It acts like the VSS is failing once it gets hot..... is that a normal failure mode for a VSS?

So are the wires going into the tranny under the aircleaner where the signal comes from the VSS and tells the tranny how to shift? And.... what'* a PM?

Thanks for the help, by the way.....

No, the VSS goes to the PCM first, along with the trans wiring connector. The PCM takes the info from the VSS and tells the transmission what gear it needs to be in. Along with a few other variables such as RPM, trans temp, eng temp etc.

"PM" is Private Message. You already got it

Private Message..... right. I was looking for a Prime Minister.

So.... here'* a thought. There is referrence to the "manual hydraulic override of the electronic control system" when the tranny is placed in the D3 or D2 position. In these positions, the 3-4 or 2-3 shift valve is hydralicly forced to move. If I take the old girl out and get her all hot and bothered till she starts acting up, and then shift into the D3 position.... the problem should disappear if it'* electronicly caused... ie the VSS or Wiring. And if it'* internal to the tranny, it should continue. What do you think?

Give it a shot. Couldn't hurt anything.