I'm in the process of swapping a 700 trans from a '91 Astro into an '87 Astro. Both have a 4.3L TBI motor and are otherwise identical, but the van has a cable-driven speedo and the replacement trans has a speed sensor for an electric speedo.

Obviously this will result in the speedo not working, but how will it affect the ECM? Will it drive reasonably well, or would it be useless to try to drive it this way?

Has anyone tried swapping the components in the tailstock to change from one type of speedo drive to another? If so, what all was involved in the swap?

(This isn't entirely OT btw, as I soon will have to modify a Berlinetta 700R4 to work on a TPI Camaro w/ cable-driven speedo!)

 

Simply take all the elecronic stuff off it and put the mechanical stuff in it's place. It's been brought up on the board here several times, check the archives.

 

my bad. thanks!

 

Grav, I just had to do the same thing. My trans was an s-10 tranny I had built, I recently got a camaro body. went to the jyard and got the tailshaft housing for torque arm complete with mech speedo assy. The problem is the gear on output shaft for elec speedo is pressed on, just carefully take a cutoff wheel and put a slot in it, it will relieve the pressure and it will pull right off. Just replace that gear with the plastic helical cut gear and clip and your set.