[95 S_Trucker]

His 99 suburban is a GMT400

This post should be in the 88-98 section.

OP, It was only 15 hours between posts. These sections get a lot less traffic than the 67-87 sections.

So let me get this straight, you put a 243 where a 246 used to be? The switch, wiring, and control module is all different between the two.

If you want to keep the np243, I would go to a salvage yard and get all of the wiring you can for the transfer case. That includes some underdash wiring. I would also get the switch and control module.

It would be easier to get another 246(or have your old one rebuilt) and repair all of the wiring and install it.

You could get a 241, but that would still mean wiring changes(to get the front diff actuator worked and the get the signal to pcm to change shift points) and you’d have to cut a hole in the floor and run wiring under your carpet.

I would not get a 261. It would have a 32 spline input(instead of 27) and they never came in GMT400 trucks, so you may need driveshaft modifications.