I have an lq4 and 4l80e in a c10 truck with a 411 pcm. I have an autometer speedometer hooked up to the 4k vss output. The speedo reads 10mph at about 60 after setting the correct tire size. The pcm is controlling shift points correctly with these settings. Is there something I am missing to get an accurate reading from the speedometer?

 

Specifically which Speedometer are you using??? I would like to see what it requires Vs. what it migh be seeing from the Vehicle.

 

I just looked on Auto meter's website and It looks like the Electronic Speed-O's have a way to calibrate them. Not sure if the one your working with works in the same fashion but the claim it's similar across there product line of Electrical Speedo's. Here is there you tube clip.

Calibrating Your Auto Meter Electric Speedometer- HD - YouTube

 

Thank you for the link. Seems like that will do the trick.