How to Check Locking Hubs for Binding

Dear Car Talk

Dear Car Talk | May 05, 2016

Dear Car Talk:

I have a '95 Toyota Tacoma. It has 152,000 miles on it and four-wheel drive with locking hubs. When I run it in reverse in 4WD high or 4WD low, it seems to bind up. I have changed the fluid in the pumpkins and transfer case, and found no metal. Do you have ideas on where I should start?

-- Michael

At your closest Toyota new-car showroom, Michael.

Actually, my guess is that one or two of your hubs are binding up. They do that when they get a couple of decades of corrosion on them.

You can test the theory by engaging 4WD, shifting the truck into reverse, and putting it up on a lift. My guess is that you'll see only one of the front wheels turning backward. That means the other wheel is experiencing some resistance.

To find out how much resistance, you'll need to stop the wheel that's spinning and force the differential to make the other wheel turn. We usually do that by having the dumbest guy in the shop hang from the spinning wheel. After he goes around a few times and bangs his head on the fender liner, he can sometimes bring that wheel to a stop. And if he wasn't the dumbest guy in the shop before, he is by then.

A safer approach is to use a six-foot pry bar and jam it between the fender liner and the tire. If you can't get the spinning wheel to stop and the other wheel to start turning, then you probably have a sticking hub on the side that's not turning.

You may be able to take apart the hub and clean it up. So try that before you look for a new one, Michael. 

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