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-   -   700r4 : Going from electronic VSS to cable VSS? (https://www.thirdgen.org/forums/transmissions-drivetrain/751973-700r4-going-electronic-vss.html)

Camaro-3 03-30-2018 01:41 PM

700r4 : Going from electronic VSS to cable VSS?
 
Hello,

I have bought my camaro without transmission (shell) and originally, the VSS is cable driven on the car. (see the pictures below to have a better idea, but it's not MY tranny)


https://cimg1.ibsrv.net/gimg/www.thi...c46e3e8e51.jpg

https://cimg9.ibsrv.net/gimg/www.thi...9c5eda2375.jpg

https://cimg4.ibsrv.net/gimg/www.thi...0b3b2b4729.jpg

I have bought a 700r4 transmission to install on this car, but the speedo bullet on the tranny is electronic instead of cable.
I want to change the speedo bullet by a cable one like on the third picture and order the right gear on summitracing.

I want to fix it as cheap as possible without removing the entire transmission tail. Is it easier/cheaper to change the entire speedo unit on the dash for one from a later camaro? For a used one, mileage is not so important for me...

Drew 03-30-2018 02:39 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
No. It's easiest to change the gears/sender to match the car/gear ratio. If you have to change the drive gear on the tail shaft, it's four bolts to remove the tail housing, and depressing the spring clip to slide the gear off the shaft. It's EZ.

jmd 03-30-2018 11:07 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
GM made the 700-R4 with speedo gear-driven VSS (in the third gen)
and they also made the 700-R4 with a reluctor wheel style VSS.
Pop the VSS out and see which you have.

The speedo gear on the output shaft may be correct and you can swap just the outer driven gear and sleeve. You need to know the rear gear ratio to figure what gear(s) you need.

Or, if it is a reluctor wheel VSS, you will definitely need the drive gear and retainer clip. Not a huge deal.

​​​​​​​It doesn't take much effort to fix it right, either way.

Camaro-3 04-02-2018 02:57 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 

Originally Posted by jmd (Post 6211212)
GM made the 700-R4 with speedo gear-driven VSS (in the third gen)
and they also made the 700-R4 with a reluctor wheel style VSS.
Pop the VSS out and see which you have.

The speedo gear on the output shaft may be correct and you can swap just the outer driven gear and sleeve. You need to know the rear gear ratio to figure what gear(s) you need.

Or, if it is a reluctor wheel VSS, you will definitely need the drive gear and retainer clip. Not a huge deal.

​​​​​​​It doesn't take much effort to fix it right, either way.

It's an electric connector instead of an hole to bolt a VSS cable, but I don't removed the VSS yet. Is it possible to have an electric VSS with a connector, but with a gear on the shaft instead of the reluctor wheel?

I think the picture below show a gear driven VSS with electrical connector instead of cable (1985-1992 700r4s?), so this one is compatible without removing the tranny tail?

http://www.chevythunder.com/speed_sensor%20700R4.jpg

And the other picture below a full electrical VSS (1993+??) with a reluctor wheel which need to change the drive gear from the output shaft?

http://www.chevythunder.com/speed_sensor%204L60E.jpg

Drew 04-02-2018 05:04 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
Yes and no. Even if the current electronic VSS is gear driven, the drive gear in the tail shaft probably isn't the right one to mate with your existing speedometer gear. They might fit together and make your speedometer read something but that speed probably won't be correct unless you swap both gears to match your tires and gear ratio.

If you pull the VSS and it's just a nothing on the end of the sensor, you've probably got a reluctor wheel on the output shaft, that you'll have to pull off and replace with a gear/clip.

Assuming your donor transmission is out of a thirdgen Camaro or Firebird, you should be able to swap the parts from your old transmission. If it's not, it won't have the torque arm mount anyway, so you'll have to swap the tail shaft housing from your original transmission. Either way, you're probably going to be pulling the tail shaft housing. It's stupid easy, might as well embrace it. It'll take less time to actually pull the tail shaft off than it took me to reply to this thread.

Camaro-3 04-08-2018 05:50 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
When I bought this car, it was a shell without engine and tranny, so I have only a 700r4 from another car.

GOOD NEWS!

I have removed the speedo bullet and it's a plastic gear! Let's see what it's look like (real pictures below) :

Check this site and calculator for reference :
http://www.tciauto.com/tc/speedometer-gear-calculator/

The drive gear is red, which is 17-tooth
https://cimg4.ibsrv.net/gimg/www.thi...cfb20aa1e.jpeg

The driven gear is lime, which is 45-tooth with a more cone shape than other gears from cable driven 700r4's, which are more flat.
https://cimg5.ibsrv.net/gimg/www.thi...14279af22.jpeg

The speedo bullet is about 2 1/16 inches diameter.
https://cimg8.ibsrv.net/gimg/www.thi...ecf9e13ec.jpeg

https://cimg9.ibsrv.net/gimg/www.thi...e5d54925a.jpeg

I used the calculator (see link above) and it's seem I will have only a 5% error margin from the real speed according to my 26-inch diameter tires.
So, if I read 50MPH on the speedo, the real speed will be 52.5MPH, which is not so bad.

Drive gear teeth : 17
My axle ratio : 3.23 : 1
Tire diameter : 26 inches

So the optimal driven teeth number will be 42.5teeth and the lime driven gear is 45.

Do you think I will need a more flat-shaped (instead of cone shaped) 45tooth driven gear to install a cable driven speedo bullet instead of electric, or I could keep mines and juste buy a speedo bullet? I want to order parts from summit and make sure to order the right ones.

Lime 45-tooth driven gear (more flat than mines, so it's not exactly the same than mines but same diameter and tooth number)
https://www.summitracing.com/int/par...0032/overview/

2.1 inch speedo bullet (40 to 45 teeth, cable driven)
https://www.summitracing.com/int/par...0023/overview/

It will be nice if I don't have to remove the tranny tail if possible, even if you say it's easy.

sofakingdom 04-08-2018 06:04 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
Not sure of Summit even has all the gears.

Go here intstead. https://transmissioncenter.net/?swoo...-gears&paged=1

It's all WAAAAAAYYYYY 2 eeeezy. It's just a "car", after all. Billions and billions of em on the roads of the universe. Lots of REALLY STOOOOOPID peeeps can manage it; you're smart, you can too.

Camaro-3 04-08-2018 06:09 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
I regret not removing the tail when the tranny was outside the car... It's pretty easy normally, but I hate my scissor lift for that... It lacks of place to work on the middle of the car and I must remove the crossmember. It's doable but... I prefer not remove it and save the price of the drive gear too!

Drew 04-08-2018 08:14 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
Red drive gear is an "A" 17 tooth, with 3.23 gears and a stock size tire, you need a Y driven gear, aka 44 tooth Dark Gray. GM # 25522495. Of course that's a 1992 part number, so you'll probably want to just look for the color and tooth count. You'll also need the cable style sleeve for 40-45 tooth driven gears. It'll be the one that says "41 42 43 44" on the side. Usually you can find the parts on Ebay for the same or less than anywhere else. (edit: For example, you can get the sleeve and 44T gear for about $40 shipped on Ebay).


https://cimg2.ibsrv.net/gimg/www.thi...387174e839.jpg

Camaro-3 04-09-2018 06:49 AM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
[left]Thank you! If I plan to install my set of 255/60r15 tires instead, Ill have 27 inch tires instead of 26. According to your chart, i can use the grey 44 tooth with red 17tooth which fits for 26 inch stock tires. But according to this chart i could use Bigger 27 inch tires with my 3.23 gear ratio if i use the combo of my 17 tooth red gear with Green 42 tooth Gear.
http://www.73-87.com/7387garage/drivetrain/speedo.htm

articwhiteZ 04-13-2018 09:01 PM

Re: 700r4 : Going from electronic VSS to cable VSS?
 
what type is the GM vss ?

below to work with auto meter speedo
Speedometer Senders The speedometer is designed to operate with an electrical speed sender. The speed sender signal range must be between 500 and 400,000 pulses/mile (310 and 248,500 pulses/km). Any speed sender or electronic module that meets the following two conditions can be used: 1. Pulse rate generated is proportional to vehicle speed. 2. Output voltage within the ranges listed below: • Hall effect sender, 3-wire (5 to 16V) • Sine wave generator, 2-wire (1.4 VAC min.) • 5V Square wave (CMOS) Recommended – Auto Meter Hall effect sender, 3-wire 16 pulses/revolution. 5291 Standard 7/8 – 18 thread


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