I have replaced the speed sensor on a 1985 five times with 3 different manufactures. The latest with an AC Delco. They all work the first time you drive it then doesn't work again. I found the wheel on the shaft makes contact when 1st installed therefore it works but then works back just enough it does not make contact again. The vin comes back with a manual transmission however it has been changed to an automatic somewhere along the way. I have also checked to make sure there is no movement in the shaft that would indicate the bushings are worn and causing the shaft to be moving. Can anyone suggest what I need to do or what the issue may be. The sensors I have used are as follows...BWD #8034--Echlin #VSS207 and the latest AC Delco #213-198.

 

What 'color' is the drive gear on the output shaft and what tooth count are you attempting to use on the VSS?

****** I'd attempt a driven (VSS gear) that's 40 or more tooth count) with the VSS you've got. I'm guessing that what you're using is 'less than'. Somewhat of a WAG but it's where I'd go. If you thought the rear to be a stock 3.07 still from the '85 and it had a D44 I'd try a 42 tooth were tires 255/16 or 275/17. I don't know that I have NOS 42 tooth or not. I've 42 or 43. but without looking - I recall NOT what for sure. Where are you located?

 

It is discolored but either dark red or dark orange and I used the same gear off the VSS I originally took out. (The original VSS did not have any voltage when I put on drill and tested) . The color on the shaft and on gear are the same color.

 

Red would be appropriate for a 4L60 drive so you need to count teeth on the driven used on the VSS. You realize you're looking for AC Voltage? You also need to make sure the drive (RED) isn't cracked and that the retainer to the output shaft is latched.

 

Yes checked for "AC" voltage, we have checked the gears to ensure there are no cracks.

 

You still haven't mentioned 'tooth count' for the VSS gear!!!! Is the 'drive' anchored to the output with the retainer? How did you check?

***Your only other possible issue is and it's very difficult to confirm. Those after-market #'s are generally considered valid for an M6 in a C4 and I've never attempted to use in an early 4L60. The 'perimeter' connector like you're attempting to use very likely won't orientate correctly on a 4L60 extension. Have you removed the retainer/clamp in an effort to better orientate the VSS. that could only be accomplished if you knew that you were using a 40+ tooth count. The VSS you're attempting to use has a propositioned retainer/clamp I'm sure.

 

I need to pull it back out of the vehicle to verify tooth count and I will let you know. I do know the "original" sensor is VERY difficult to find if you can find, it was more a rounded electrical connector so it was changed to the style you can actually get (the ones we are using) we know this because it has a new harness wired on it. In checking as best we can with what we have the assumption is it should work? But you know what they say about assuming anything!

 

Since you need to recount just confirm again color of drive while there,, that it's actually retained properly (your situation is similar to what's experienced if gear is cracked/retainer busted etc - get's warm and drive gear slips on the output). I don't have a NOS any longer for your application and I believe only one used. I haven't had that one in my hand for quite some time.

 

Don't have a rack open to lift @the moment, they tell me 37 teeth

 

That VSS needs to see a 40+ tooth count minimum. 37 won't work. What size tires?

 

245/45/17 is tire size

 

You've many issues. Do you just want to make the speedo operate or actually 'correct it'? You mentioned you thought the car was originally a MT so it might be important to do the axle ratio calculation using the 1 wheel rotation and counting pinion rotations. I'd think you or someone in the shop would understand that.Using the VSS to make it work you need a 40+ VSS gear. That won't confirm everything because I wasn't sure there was actually sufficient clearance to use that in a 4L60 transmission.. You get a 40 or greater tooth count gear and if the 'drive/red' is in the correct location on the output-shaft and provided that the VSS seats fully the speedometer should 'work' but not correctly.

Do the rear axle ratio calculation and I'll try to suggest a gear - you're sure of the 245-75R17? Ratios expect something 2.59 to anything above and beyond. If the car was actually an MT and still stock rear axle expect 3.07 maybe.

I asked before - where are you located?

 

Sorry I did not see where you asked, North Carolina and fat fingers this morning the tire size is 245/45/17

 

The customer just got the car so he does not have a-lot of information on changes. The reason I said it was originally a manual is the Dealership checked the vin to give me OE part numbers for the speed sensor. That's where we got the number for the Delco one we were able to find and change out. When we originally got the vehicle the nothing worked on the cluster so we removed and he had rebuilt, @this point the speedo was inop so we removed the speed sensor and found no A/C voltage. Since the OE that we took out is obsolete we were told a sensor for a newer vehicle would work, thus replacing with the BWD #s8034 and changing out the harness/using the gear off the sensor we removed. It worked for about 100 miles if I recall correctly. Then replaced with another BWD and that's when it would not work more than 1st test drive. Replaced with the Echlin #VSS207 same thing, Then this last time with the Delco #213-198 same...that brought us to this point..Oh I will say sometime is all this the customer did change tire and wheel size...he orginally had bigger wheels and tires that rubbed when you turned on the front. I will call him this morning and find out @what point he replaced wheels and tires if that makes a difference....

 

Call a local GM dealer and see if they have or can locate any of these #'s

25513047 (40), 25512048 (41), 25513049 (42), 25513050 (43), 25513051 (44) or 25513052 (45)


None would correct speedo but any one of them if all else is correct should make work consistently.

I actually 'doubt' a dealer could have decoded an '85 VIN to components - It might be interesting to look in the rear storage compartment and see if there's a SPID label with RPO codes. VIN on the SPID should match the windshield VIN and the driver door. If label is there take a snapshot of it and post it OR under my user ID is an email link - send it via email.

Tire size looks like I misread what you typed.

If you took out a 37 tooth I'd think the car an AT always and you'll find a 2.73 ratio if still stock and you check!


I'll bet ya'll wish you had never seen this guy and his car!!

 

Oh you just don't even know! Very patient and nice guy but this car is ridiculous. Looks like the whole front clip has been cut off and a hack job on the welds from some hole in wall body shop! He doesn't mind paying us though so it's not like dealing with so crazy guy-which makes it ok....I know more about corvette transmissions, speedometers and rear ends than I EVER wanted to know for sure!!

Thank you for all your time, patience and help! If we change the gear on the VSS do we need to change on the Tail shaft as well?

 

I've never owned an AT transmission Corvette and I've never attempted that VSS in a Corvette with an AT because I always doubted that it would work. The location of the drive on the output-shaft and the contour of the 4L60 extension I thought might interfere with correct alignment/retention. At this point since you've the VSS you buy/try any 40+ tooth to make work. To correct it requires substantially more effort.

To make the speedo 'operate' you can leave the red/drive where it is. Don't need to change anything there. I'd be interested if after you get a 40+ gear that you can actually get the VSS to seat correctly. Make it a point to post back what you find.

 

You mention working for 100 miles maybe - That could hint that either the RED/DRIVE or the 37 tooth OR BOTH were compromised by a 'partial' engagement/mesh and maybe you will need to go further and actually check the condition of at least the RED/DRIVE You want to see sharp/uncompromised' teeth on it. This is used with likely acceptable wear. GOOGLE 8640517 GM for other visuals.


https://www.ebay.com/p/17-Tooth-GM-A...-Red/658507440