You also could swap the vac system for a pull cable to actuate the front dif. Rex has a great write-up on it here: https://blazerforum.com/forum/builds...r-build-66048/

 

Mine is acting up as well, it sometimes will go into 4Hi and that button stay lit, sometimes it wont, and can feel its still in 2wd. I am on the hunt for a DIY cable posi-lok! Just wondering on that system how you get it into 4Lo

 

your only capping the actuator vacuum line and using the cable to engage your front axle. You will still use the buttons on your dash

 

matt4x4: classic case of needing to reflow the solder joints on the 4x4 switch assembly. Another easy thing to do....just need to be careful taking the assembly apart and using a solderin iron...not a soldering gun.

 

The differential cable was stiff, replaced the cable and actuator. There was a fluid in the damaged actuator. Didn't think of tranny fluid. The vacuum switch on the transfer case was replaced approx. 4 yrs ago. How do you flush the vacuum line?

 

just buy new, 5 bucks

 

I tore through 3 of these actuators too. The last two I bought from NAPA and they did not last more than 2 years each. Between the vacuum issues, cable issues, and transfercase switch issues I decided it was time for the Bravada front axle swap.

 

chucknugget: could you explain more about the Bravada front axle..why it is better/different???

 

No axle actuator on the Bravada front axle. The front differential is live all the time, not necessarily powered, but live. Just like the NV236 when "Auto" is selected. More drag, less fuel mileage. Also, it only has a single speed transfer case.

 

Thanks Captain....my '02 Blazer has the NV236 and I have never even tried the "Auto" button. Guess I would need to go find some sand or something to see if it works....might have to do that....one of these days.

Thanks for the info.