all the lights flash on my 4X4 controls while service 4X4 light comes on and sounds like motor in engaging and dis-engaging the 4x4 motor happens often but only for about 3-5 seconds. It happens in 2 wheel 4 high 4 low and auto 4x4. Then later on in the day it seemed like once in a while the clutch was slipping loss of power then all of a sudden click back in and work fine again (i was about 20 miles in the bush when it started had to get it home it made it but scared i damaged it more after slipping started??)

 

Having the same problem with my 1999 Blaze too. 4 button.

Any takers?

 

I'll say the same thing that I say in just about all of the posts about the NV236 like this. The Service 4wd light is just like the Check Engine Light. It means there are stored codes. There is no use guessing what the problem is when the truck will tell you. Trick is getting it to someone that has the proper scan tool to pull the codes. Most autoparts scan tools are not capable of reading the TCCM.

 

I don't know if it helps and I'm no pro but I had a similar problem with my 96 blaser.
I took it to a transmission shop that said there was nothing wrong with the transmission. They directed to a top auto repair shop in the area with all the electronic bells and whisles. They diagnosed it as a faulty Traction Control Module and it cost me approx. $1,700.00 with parts and labor in 1999. There was no core charge on the module. It ran great after that with no problems.