My truck is a 4x4 1989 Chevy s10 4.3 6 cylinder. It has a fuel injected carb? (I have no idea what that means, but my brother told me that)

Ok i figured out that the engine does have a vaccum leak where the carb connects to the engine block...Im getting a new gasket for that this week.

Now i find that the truck does not like to go into 4x4 mod on any of the speeds.

Its got a **** under the dash for switching into 4x4, no locking hubs.

Theres a diagram next to the **** that shoes the back axle in orange and when I go into 4x4 the front axle lights up orange. I assume that the back axle is always engaged in drive, making it a rear wheel drive vehicle when in 2wheel drive.

However, when i try to get it to go into 4hi, it will light up just fine, but going back to 2wheel, the front passenger wheel makes a whirring noise likes its in 4lo or something. So I have to put it back into 4hiwhile in neutral (of course) thenshift it back in to 2wd. Sometimesthe light on the diagram lights up, sometimes it flickers and goes out, when that happens I get the wirring noise. [&:]

Trying to engage into 4 low works only if I shut off the engine shift it into 4lo then restart.

My brother says it might have to do with the vaccum leak in the carb thats causeing the engine to idle too high making it so the gears dont mesh. But Id like to know what that wirring noise is when its in 2 wheel drive.

 

I see you already started a thread concerning this issue. Please confine things to one thread for each problem. Anybody wishing to respond to this post can do so in the original thread.