autometer speedo / 4l80e trans

[69muscle]

i am putting in a 4l80e trans and running a autometer electronic speedo. what do i need to connect the two to work together. thanks for the help.

[Steve Chryssos]

The good news:
You simply splice the sender wire from the speedo to the VSS (aka TOSS) coming from the tailshaft of the transmission.
The Bad News:
Your uncalibrated speedo might confuse your trans computer. The trans may not want to upshift out of first gear. What trans controller are you running?

If that is the case, I strongly suggest that you add a male/female connector along the length of that sender wire (preferably locate the male/female connector somewhere under the dash for easy access. That way you can unplug the speedo sender wire until after the trans calibration is complete.

Once the trans is calibrated you can set the speedo as follows:
Raise rear wheels by putting jackstands under rear axle such that rear wheels are 2" off the ground. Chock front wheels. Start car and put in gear. Push odo button to start calibration process. Take foot off brake and apply throttle. Just spin the rear wheels for a while and watch the speedo's digital calibration counter. When the counter runs up to about 2500 or 3000 (pulses per mile), you should have a rough calibration. The speedo will be sending enough data to not confuse the transmission.

Now that the speedo is kinda working but not accurate, you can head out on the street and do a formal calibration for accuracy.

[69muscle]

hey steve thanks for the info. the controller is from tci and i think they are built by f.a.s.t trans,converter,cooler is all tci and a paddel shifter from twist machine. it's all going in a 68 convrtible with a 496 big block. so all i will need is the pig tail from my local chevy dealership and tie into the speedo input in and then speedo output back to the pig tail? or am i missing something. thanks for your help.

[Steve Chryssos]

More than likely you will need to do the male female connector in the sender wire then. Not a biggie. Just something to remember when the damn thing doesn't want to upshift out of first. That pigtail sounds like a useful part. Get me the part number if you can.
Thanks
/S

[68 SuperRam]

Couldn't you just put somekind of one-way diode in line - so that the signal only goes to the speedo - similiar to isolating shock sensors in alarms. - That why the speedo will never affect the computer?

[justforfun]

I have not done this yet (but will need to in the next 6 months), so hopefully it is not a stupid question. If you are running a stock late model PCM can you just use the output from the PCM instead of the signal from the trans?

[68 SuperRam]

Not certain - I am currently doing a swap to a 4l60e - and using the TCI computer - learning as I am going - Steve is very helpful in his pointers.

Just makes sense to put the diode - just to isloate the signal out of the tranny - so that the computer will never be confused from feedback from the speedo - if any.