Originally Posted by
Phestezio
Well I gave the van its maiden voyage and I do not have any speedometer so something isn't right. BTW this is in a sprinter van so I effectively changed gears and tire size since I'm using the sprinter rear end and tires. The tire size is only about 1/4" larger than the Silverado tire diameter but the gear ratio on the Silverado was 3.46 and the Sprinter is 3.92 so I expected the speedometer to be inaccurate without running the tire/gear wizard but I do not have any speedometer function at all.
From what I gather looking at wiring diagrams the 4WD 6L80 has a VSS on the transfer case but the 2WD 6L80 does not have a separate VSS and uses the TOS for vehicle speed. However it also looks like it was using the wheel speed sensors for vehicle speed based on the settings in the speedo tab from my factory file and not sure what the gauges were using for its primary input for vehicle speed since that is Serial Bus data but its obviously not happy with something since its not working haha.
As a side note the van actually drove pretty nicely considering everything I have done. The only thing I noticed was some slight shifting flares, not sure if its because of the missing vehicle speed or the tune yet but they are pretty slight, maybe about a 300-400rpm flare past 2nd gear. I need to hook up the scanner and see if I can see vehicle speed in the ECM/TCM and if its just not displaying that data to the gauges.
I really appreciate any help or advice, i'm not afraid to say i'm a noob when it comes to tuning but I have been a tech for about 16 years and have a little bit of computer programming experience so I have a good understanding of how the PCM/TCM etc. function. Trying to determine if its a configuration issue or a physical wiring/sensor issue but also don't see much harm in playing with the speedo settings to see if they change anything.