4x4 not working??

[SSpeedin]

I have a 1988 Chevy Cheyenne pickup, with the 4.3 liter v6, it has the 4 speed manual tranny. I just bought the truck a while ago, but i just noticed the four wheel drive doesn't work. is there a trick to how you put it into four-wheel? i just sat in neutral, and moved the lever to 4high. any other ideas? im planning on looking at it tonight, but not sure what exactly to look for. Thanks!

[asilverblazer]

Could be a thermal actuator, I hear they are a common fault. Although that's not saying it is what's wrong in your case.

[davegee]

If your truck is a "newer style" 1988 ie: same as 88 thru 94 style truck, GM has an updated electric conversion front actuator instead of the slow "wax" style actuator. A new wiring jumper and the new style actuator are installed, and the result is almost instant in and out of 4x4. The old style can take some time to go in or out, especially when it is cold out. The upgrade is definitely worth the few extra bucks.

[SSpeedin]

That was the problem.. thermal actuator. I decided to just replace it because i have limited time as to how long i can use my shop, so i needed to fix it now, otherwise i would have gotten that upgrade. thanks for the help!