speed sensor

[97 silverbullet]

so has anyone replaced the speed sensor? Did your abs and traction control off light come on before you replaced the sensor?

[jerryindiana]

my check engine light would come on every once in a while and my cruise control would work sometimes and sometimes it would not. I had my speed sensor changed and no more problems

[Sweet William]

First off it is a speed sensor that tells your cars computer how fast the transmission input shaft is turning. Without this information my car did not know when to shift, and when it did shift it was very harsh. Can you drive your car with this code present? Yes you can, for how long your transmission will last like this I don’t know. Mine shifted so harsh that I was afraid to drive it very much.

Some of the generic transmission manuals call this sensor a “turbine speed sensor”. On the 4T80E transmission it is mounted next to a gear that comes off the input shaft, which is behind the torque converter. I assume that the “turbine” the manuals refer to is the torque converter. I was quoted 12+ hours labor plus parts by the local GM dealer to change the sensor. The service manager quoted around $1200.00 for the complete job. I decided to tackle the job myself. But first I had to ask myself is this, why is the code present? Is it really the sensor? If it is the sensor, is it worth doing all this work just to change the sensor when my car has 148,000 miles? I guess the real question is “should I just let a shop rebuild the transmission and change the sensor”.


Can you do the job yourself? I would say that if you just own a basic set of tools and just do things like change your oil and plugs, you should probably stay away from it, if you are not afraid to tackle an engine overhaul yourself I would say that you should be able to do this job as well.

The speed sensor can be changed without removing the transmission from the car. The engine/transmission can be lowered to access the transmission side covers and the end plate. It is located inside the transmission. The sensor is located next to the sprocket for the input shaft. The sensor is held in place with 2 6mm bolts, one for the sensor, one for the wiring harness.

[dsatt12]

I got the impression from the ABS and traction control that you were asking about the wheel speed sensor, and not the input speed sensor from the tranny.

My traction off light has been on for 4 1/2 years now without a problem, though the ABS still works flawlessly oddly enough. I've had the codes pulled that even said it was the front right sensor that was bad, though my scanner doesn't read them.

If you are looking at replacing the bearing assembly (w/sensor) here are some great instructions: http://www.automotiveforums.com/vbul...d.php?t=143898

[RoraStar96]

http://aurorah.proboards20.com/index...num=1091471732

Pics included as well.

There is a big difference between the VSS and the WSS, the WSS is part of the wheel hub assembly. Not hard to change IF everything goes as expected.

Most times though...it wont..heh..

[dsatt12]

Gaah! To my shame I'd yet to visit the ACNA boards. But with info like that, how can I resist? Now I have more stuff to read and keep caught up on dang it...

[taylal23]

So, SweetWilliam, was it your input speed sensor after all? I have a code coming up for this sensor in my 2001 3.5 Aurora. How much does it cost to get it replaced, especially since they don't have to pull the tranny out? I'm thinking I should just change the solenoids first and see if this cures my problem, if not, then get the input speed sensor changed.

[taylal23]

I finally got my OUTPUT speed sensor replaced. Turns out I had 5 codes come up when the diagnostics were done. I took it to a local tranny shop and he changed the Output speed sensor for only $200.00. WOW! I was shocked. It took care of 3 out of 5 codes. The only 2 I have left are "secondary air injection" and "input speed out of range". These 2 have been on there forever! I think the first is a result of the second. My car (a 2001) is in the shop now getting the INPUT speed sensor replaced (which is in the tranny). And get this, he's doing it for $300!! I'm shocked again!

My car jerks when changing gears, but only sometimes it does it. It's been doing this for some time. I'm certain it's the Input Speed Sensor. I'll update this when I get my car back to see if it's running normal again. I sure hope so...that jerking makes me want to drive my car into a ditch.