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The connector on the VSS of my 89 700R4 is broken and want to replace the unit. I found a stock unit but they want too much. I found this instead and does anybody know if this will work? Thanks
The tail housing of the 700R4 I don't believe will accommodate the connector of that later VSS. What is the part # of the one pictured? What ratio is your '89 700R4 rear axle?
I checked the size and does fit in the 700R4. The Delco P/N is 25007308. The gear in my 89 is 2.59 and the plastic gear does fit on it
The 'pictured' VSS is NOT a 25007308 - that # was discontinued way back in maybe 2003. You say you checked? How & what did you check? That part # also was for a 40+ tooth driven gear and yours certainly isn't. I'd think yours with a 2.59 should be 36 and likely 'white'.
You have it 'in hand' NOW? If you do and there's a number stamped into it I can tell you if it will or won't.
So you DO NOT have it 'in hand'? If you found one that actually had this information 'ON IT' - it could be used. You don't need the short adapter. It would be easier to just use a connector, terminals and repair. IT MUST HAVE THAT NUMBER ON IT TO WORK!
Is your 'center' electrical connector just busted or the VSS actually?
Well I want to say it's white but it's so old it's turned to a dull orange and not black
It takes a very straight forward Weather-Pak and I've seen a couple people actually clean one and 'DuraMix' a new Weather-Pak to it.
Post a snapshot of yours. Yes you should be able to check operation BUT it wasn't unusual for that type of VSS to actually leak through the connector. Be very careful removing it, Many have destroyed the VSS removing it.
A GM# 12126452, ACD PT723 or equivalent would be a correct repair 'pig-tail'. eBay has images but I'd think a local buy would work.
OP - Depending on the condition of the actual terminals on the VSS, the easiest check would be a new connector to the VSS I believe 'without' removing it from the transmission. You can't do anymore damage and the car remains drivable. That's why I asked for a snapshot of yours. If it's leaking now from the center where the terminals are then it's already likely a better choice to maybe replace with a correct one.
The tranny is out and was getting ready to get it rebuilt when I found the connector broken. I did find a new OEM part but the price was too much. The one I showed they say is a replacement cause they don't make the original any more. I need to find out what voltage range the VSS is
Standard logic sensor voltage in automotive is 0 to +5 VDC for VSS. The signal is best analyzed on a oscilloscope as a two wire sensor is either 0 to 5 volt rectangular pulses with duty cycles of 40% to 60% as standard or an inductive sensor that is sinusoidal (typically wheel sensors for ABS) +-5 or 3.3 vdc. Three wire VSS uses positive +12VDC input, GND, and sensor output using hall effect rectangular pulses. ALL VSS signals are counting pulses to calculate speed (think RPM of engine as similarity).
The VSS is a PM Generator so I'd think you read voltages in AC. I'm quite sure the FSM mentions AC. Dependent upon the speed of the rotational device used to spin it maybe something greater than 5V AC to maybe something as great as 75V AC
Voltage peak magnitude does not increase, think about alternator or generator as example. The 'off' duty cycle decreases with speed so an averaging measuring device such as a multimeter will show an increase in average voltage but that is inaccurate which is why an oscilloscope should be used. You will then see a fixed magnitude with frequency increasing. As a simple check with multimeter, if the average voltage increases with rotation speed then the sensor surely works...even if the measurement is not really telling any specification of the part.
Voltage peak magnitude does not increase, think about alternator or generator as example. The 'off' duty cycle decreases with speed so an averaging measuring device such as a multimeter will show an increase in average voltage but that is inaccurate which is why an oscilloscope should be used. You will then see a fixed magnitude with frequency increasing. As a simple check with multimeter, if the average voltage increases with rotation speed then the sensor surely works...even if the measurement is not really telling any specification of the part.
Mid to late 80's I was taught to assume that if a PM Generator/VSS displayed AC Voltage then it was assumed to be 'functional' and to move on. Yes more sophisticated equipment that many/most don't have can certainly evaluate performance much better. In most cases with GM VSS of the 80's and early 90's that should suffice, I get what you're saying but for very basic VSS works/doesn't work it's not required.
Yes, i agree with you. I am a bit nerdy in the engineering lab all day and had to reign in the 'proper' way and realize how most people would approach the solution. Thanks. Hopefully we helped OP out.
VSS replacement
