Need Wiring Diagrams!

[chevycrew]

I having issues, trans wont shift in 4 lo, or double low.

Im thinking that the PCM may use the rear speed sensor for the traction control setup. While my speedo works fine, i dont know if the pcm is getting the correct speed to shift at.

I can just splice the 2 rear sensors together and bypass it that way, but I'd like to see how the factory has the system wired.



Oh yeah, think I broke my front locker already...

[djthumper]

This thread has a link for the diagrams and what not. http://forums.offroadtb.com/viewtopic.php?f=7&t=1742 I checked the link out and it was working still.

[Trail X]

Steve, I posted this link in your build thread, but here it is again. There are a few good resources in there that may help you:

http://www.offroadtb.com/articles/tech- ... -documents

My understanding is that the speed sensor off the back of the transfer case is what the PCM usually uses as a speed input. How is yours currently wired? Do you have any speed sensors feeding data into the PCM?

Honestly I'm not sure how much the PCM uses that information for shifting purposes. I believe it uses calculated engine loading data from the engine sensors too.

[chevycrew]

Ok found the problem!!!

This will apply to anyone who swaps out the electric shift t-case for a manual 231.

There is an output on the transfer case shift motor that tells the pcm the truck is in 4-low. Without this input, the trans tries to shift off the mph values, since its in 4 low, these values are never reached.

You can compare an e-shift truck, to a manual shift truck in the fullsizes and find out how to correct the wiring.

Since I have dual cases, I need manual control



Thanks for the link! But, Rossler Transmission sells "The Little Black Box" its one plug, plus 2 wires, and full manual control without ever dropping the pan.