4x4 won't engage; whine in 4WL

Hi, I have a 1987 S-10 Blazer with about 80k on it. I'm having a problem, maybe someone could give me a clue as to what maybe wrong.

When I engage the 4x4 on the floor it seems to go into 4x4 but im not really sure, however the indicator light doesn't come on. I tried it on a flat dirt surface it seemed different but I need a hill or a jack. When I put it into 4WL it has a low whine to it when I drive that increases with vehicle speed. Is this a major problem? I had a new torque converter in, what should be my next step?

Thanks, Jason

"Jay" wrote

When you pull the lever in 4hi, you are engaging the t/case, i.e. you shift the t/case so that it applies power to the front driveshaft. The indicator light only goes on when the front diff has engaged. So I would suspect that you have a problem somewhere in the front diff, or it's engaging mechanism.

The whine in 4lo is normal. You need to figure out what the problem is with the front diff. It is engaged by vacuum, so the first step would be to check the vacuum lines for any breaks, check that you have vacuum down to the switch on the t/case, and vacuum back up to the vacuum motor that engages the front axle. It should be located under the battery tray on the year I believe. You can also manually pull the vacuum motor into engagement and check to see that the front axle engages mechanically. If that works, I'd concentrate on your vacuum lines.

Ian

Sell it to me cheap.

Hatt

There is a Vaccum Switch on Top of the Transfer CASE ( GM Dealer only part $18.00) Check the hoses to it and see if they Melted or dried out since they go close to the Cat Coverter. The Switch goes Bad OFTEN.. The Switch Reroutes the Vaccum to a Canniser UNDER the Battery.. this Cannister Has a Cable that runs down to the Front Differencial (pig), this Cable is What puts the Front PIg into 4 wheel Drive.. If the Front diff isnot engaged, then the 4 wheel light will not come on

Jay wrote: