700R4 change spedo to ecectric from cable

[1-PU70]

I have a 700R4 from a 87 2 wheel drive S10 Blazer in my 70 C/10 with a cable for the spedo. I want to change to an electric spedo. If I change the tail shaft housing with an electric pickup one and pull the plastic gear of the tail shaft do I just press on the new exciter and how do I know where it needs to be on the tail shft. I hope thats prity clear. I want to switch from a cable spedo to a electric spedo.

[71swb4x4]

If you don't want to change the tailshaft you may be able to get an adapter from www.jagsthatrun.com that will screw onto the mechanical part and send out an electronic signal.

[1-PU70]

I thought of going that route but I think I can save some money with used parts from a U-Pull-It

[Russell]

As far as positioning it is concerned, it just counts how many times the thing rotates, should send something like either 2 or 4 pulses out for every rotation of the gear. If it is a 4 pulse unit, you'll need a DRAC thinger that modifys the 4 pulse signal into a 2 pulse signal that the new speedometer can use. The only units that will have an electric speedometer and a 700r4 from the fullsize viewpoint of things will be the 88+ trucks (1 tons, suburbans and blazers included)

[Huck]

I have an 88 700R4 out of a 1/2 ton pickup that has electronic pickup. I want mechanical cable drive---want to trade speedo senders????????

[meathead95]

i also have a 700r4 out of a 88 firebird formula 350 with the electronic speedo if someone wants to trade for a cable set up

[1-PU70]

Huck I will let you know about a trade. Im might be geting one this week. When you pulled of the reluctor ring do you have 2 holes for the pin that holds the drive gear on the tail shaft?

[Huck]

Don't know as i havent pulled the thing apart yet. Do know that the 87 was mechanical and 88+ is electronic on trucks. Also have heard that the 87 and earlier had some design defects that were fixed with the 88 700R4's so keep that in mind.