[1989 Bronco 4x4 XLT]

I have the two buttons on the low right side of my dash that say 4x4 and Low Range. When I put it in 4x4 it engages and works also when I shift to N and engage the low range it engages. When I put it in OD, D, 1, R, with the low range engaged it pulls itself forward or when in R it pulls itself backwards. I have to ride the brake to stop it and when it stops I have to hold it down to keep it from moving. Is this how its supposed to be? It only does it in 4x4 when low range is engaged. Sorry if this is a dumb question.

Thanks,
Ken.

 

[2011GT]

low range multiplies your torque. It's for slow speed offroading or for times when you need a lot of pulling power such as pulling a large boat out of the water.

So what you are experiencing is normal. How many RPMs does your engine idle at?

 

[1989 Bronco 4x4 XLT]

Right around 1000 rpm's. Close to that can't remember exactly. Thanks

 

[Steve83]

The high idle is the reason you have to ride the brake in low range. Use a mechanic's stethoscope or 3' of garden hose to listen for a distinct hiss around the intake manifold with the engine idling, indicating a vacuum leak. A common spot on V8s is near the center R plenum bolt (the T-40 in the top R of this diagram) where the plenum gasket (#9H486) gets sucked in.



If there are no leaks, read this:

 

[1989 Bronco 4x4 XLT]

Ok thanks I will start looking!