Dorman 600 500 4 Wheel Drive Switch Review

1998 Chevy Blazer, we replaced the part on top of the transfer case and the four wheel drive is working again. It was a pretty easy project.

As noted by another reviewer, it does not specify which transfer case it is for. If you have a 4 button 4X4 switch on your dash you will need a Dorman #600-104. It's near the top center of the firewall, follow the vacuum lines. I have an NV236 (NP8) transfer case.

This part doesn't even deserve one star. I installed this switch along with all new vacuum lines about 3000 miles ago. The switch failed, allowing the lines to fill with transmission fluid. Now they are all destroyed and need to be replaced AGAIN.

The same damn part you get at your local auto parts store but at 1/4 the price. My local store wanted $60 for the same part! Perfect fit and fit for 4x4 on 02ft Blazer ZR2 If you have Tranny Fluid pushing the vacuum line up through this switch, you have an inlet seal problem or worse with your Trans Case.

This 4x4 transfer case switch was exactly as pictured. I traded it in for my old derailleur and my 4x4 in my GMC Sonoma worked like new. The new switch fits perfectly in place of the new switch. These switches fail and prevent the actuators from getting the pressure they need to engage or disengage the 4WD. Good product. I hope it lasts as long as the previous one.

Didn't solve my problem, was quite tight but wouldn't be too bad in warm weather. Seems to be as good as the OEM part. I have defrost, vents, and foot warmers running at the same time, and my 4x4 isn't working. Most likely it's a vacuum leak or clogged hoses. Not encoder motor or vacuum switch. The encoder motor makes a noise under the driver's side and all the lights work, but the front axle does not turn on. I hope this comment has helped someone. Update: I had a clogged check valve. Through…

This was EXACTLY the part I needed - the old vacuum switch allowed a partial vacuum leak into the line leading to the hub lock actuator diaphragm mechanism, causing "gear drag" from the front axle when the Hubs also attempted partial engagement in 2-wheel drive mode. Replacing this switch ensured that the vacuum was only delivered when it was needed. The old one was stuck with the ball plunger partially depressed so the old one was leaking. An installation tip: this part will tilt forward just…