95 GMC Suburban 1500 350 4 wheel drive. Question: The 4 wheel drive will not engage. 2 yrs ago I replaced transmission with a rebuilt unit. See below -

SOURCE: 1999 Chevy 4x4 engaging

Check the solenoid at the front axel. This is a rather common prob. First check that power is at the axel, got power, clean and put it back. Please do not even look at the tranfer case! At worst you may need to replace the axel solenoid! Frankster016

SOURCE: Front drive, 4 Wheel drive won't engage

Check the switch on the transfercase remove the vacume lines if there is oil in them the switch has to be replaced and the lines should be cleaned out you should also check under the battery tray to make sure the boot is not ripped that controls the leaver to engage the front axel

Juan Rivera

• 172 Answers
• Posted on Mar 30, 2009

SOURCE: 4 lo working, 4 hi stopped working , A4WD never worked

Hi my name is Juan and I do own a trailblazer with the same year 2002 and I read the problem you have let me try to help you Have you try to shift to 4hi with your transmission in neutral ? the transmission needs to be in neutral in order to shift the transfer case to 4hi and the vehicle needs to be completely stooped also is your service 4wd light on?? if the light is on your transfer case needs service and it can be as simple as the switch inside your car or a solenoid that has not been detected by the computer

SOURCE: I have a 1990 K1500 4X4 Chevy pickup that wont

I had the same problem on my 90 K1500, it was the 4 wheel drive actuator unit itself. Bout it at the local parts store for 30 bucks and installed it in 10 minutes or less - and vavoom! 4 X 4 back in business.

SOURCE: 4 wheel drive will not engage - how do I troubleshoot

The vacuum switch on the transfercase is most likely the problem. If you remove it and the plunger is stuck in, replace it and your 4wd should engage again.