I have been doing a lot of reading and hoping someone can help straighten this out for me. My whole drive train is GM, from the 5.3 LM7 out of a 2004 avalanche, the 4l60E transmission from a 2006 Silverado, to the NP241 out of a 90's suburban with the electronic VSS on the tail housing. I have read a lot of people using a separate VSS signal before the transfer case. If I don't have to add a whole separate VSS I would like to go that route. I had read on only about 2 forums from other sites that the transmission will shift properly if it knows it is in 4 Low, and it gets the info through the PCM from the 4 Low signal wire in the harness. Can anyone confirm this, and also that all it needs is to connect to is a ground for the signal. Would definitely save a good bit of $$$ and work if that is all it really needs.

 

Did you figure this out?

 

I haven't though I am still a bit away from finishing my wiring, and starting the engine. So I was just going to proceed with the plan that it will work and put a contact switch on the shifter I am building for 4 low to send the signal.

 

i would e-mail Brendan at LT1Swap.com he probably knows what to do.

 

Any luck with this? I have a 2001 heard it was pin 16 I needed to add a toggle switch to shoot a negative signal when going into 4 low

 

On 03-06 it is pin 16 that is the 4wd signal and it needs to be grounded. I emailed Brendan at LT1swap about this for my swap. I am using a micro switch on my 4wd shifter. You could go even simpler and just add an LED toggle switch on the dash somewhere if you wanted.

 

So just a ground wire nothing needs to go back to the the transfer case

 

Nope... just a ground to Pin 16. Nothing on the tcase required. All the PCM needs to know is if you are in low or not. The speed signal comes from the VSS and when Pin 16 is grounded it performs some kind of wizardry to adjust shift points apparently.

*edit*
I was going to use the 4wd switch on my NP231 but that won't work because it grounds when you are in 4 Hi. Also I have a 2 low kit installed and it would break the ground in 2 Low so I decided on a micro switch at the shift lever.