Bo185

Does anyone know were the 4x4 6l80/90 VSS is located?

Is the VSS internal to the 6l80/90's in the 4wd trucks like the 2wd units?


The Gen III trucks have the VSS in the transfer case with a 4low switch to the PCM to tell the trucks in 4low.

If the VSS is in the trans how does the truck know it's in 4low?

And does it change anything in the tune when it goes in for low ie shift tables?

zgp

6l80e/90 sensors are inside the transmission and sent via CAN messaginging to the ECM and other modules.

Zero Gravity performance

Bo185

Even on the 4wd units? And how does the it know when its in 4low and change to correct for the lower gear ratio. Wouldn't the speedo be off?

zgp

In the new GM Controls scheme, once you select 4wd low high etc, there is a bit select that tells the TCM that you are in that state. The Transmission controller know the ratio difference and has a calculation for the ratio change internally and compensates for it.


Zero Gravity Performance