700R speedo conversion; electric to mechanical

[Tuff Gong]

Looking for help on how to hook up my original mechanical speedometer cable to an electric 700R transmission.

[notsolo]

On mine, 89-90 700r4 ..Take off the tail shaft to get to the metal pickup/gear. slice thru with hacksaw about 1/2" then put chisel in slot and crack the last 1/4" to slide it off the shaft. then you can add the drive gear and the clip. Then you need driven gear housing and the correct color/ tooth count on both of them to match your rear axle gear ratio for the correct speed. I needed longer speedo cable. Also changed the bronze bushing while the tail shaft is off.

[Tuff Gong]

That’s way out of my comfort zone. I’ll probably just try one of those expensive conversion kits. Lol

[notsolo]

It's really not that bad, but I did have the trans out at the time....what kind of kit are you talking about? Full electronic dash?

[Tuff Gong]

https://www.summitracing.com/parts/dak-ecd-100-1/

This is what I’m going to try

[54Caddy]

Call a transmission shop ask them how much to convert it to mechanical not that hard at all. Removed driveline and tail shaft housing.

[randy500]

You can pull the electric pulse generator off the tailshaft with a harmonic balancer puller and some long bolts. Then just replace it with the speedo drive gear.

[Tuff Gong]

Originally Posted by randy500

You can pull the electric pulse generator off the tailshaft with a harmonic balancer puller and some long bolts. Then just replace it with the speedo drive gear.

How easy is this process? My mechanical repair level is low!

[71meangreenc10]

https://transmissioncenter.net/ is where I got all my conversion parts to do mine. You can call them and they can see exactly what you need.

Smitty

[Tuff Gong]

Does the output shaft have to be modified to accept the new gears?

[randy500]

Here is what it looks like, you could borrow a puller from autozone or oreillys too, need pretty long reach tho.

[randy500]

I have done it like this with long bolts or allthread

[randy500]

Nut on the end behind of the allthread or long bolt to pull.

Cable type plastic gear is held in place with a small clip, which engages a hole in the shaft, i dont know if all shafts have the hole though for the clip.

[randy500]

Tail-shaft housing has a square rubber o ring instead of a gasket, its re-usable if needed.

[randy500]

The hole for the clip is there in this one, on yours it could be under the gear or whatever its called.

[Tuff Gong]

Thank you for the detailed information. I’m afraid I’m going to get it apart and find out I don’t have a hole for the clip.

[randy500]

I dont know if some dont have a hole or not. Maybe you can look it up.
Jack the rear of the truck up real high and you wont loose hardly any trans fluid.

I think there is a trans guy on the forum, clineberger or something like that, he probably knows, kwmech probably knows too,

[kaycee]

They all have a hole, You need to know what rear gears,heigth of tires to get the right combo of drive gear and driven gear and the appropriate housing.