Questions and Answers

Isuzu Trooper Locking Hubs Q. Vincent: My four wheel drive with auto-locking front hubs is not going into 4WD. I have a 1990 Isuzu Trooper that I have owned for 6 years. The 4WD used to work fine. This past spring I did a complete brakes job on all 4 wheels. One the front I replaced the rotors and Calipers. I did not test the 4wd after doing the brake repair.

Obviously I have messed something up inside the hubs. I followed the repair manual to a tee when removing and replacing the hubs (or at least I thought I did). During yesterdays first snow of the year, the front hubs would not engage. I realize that alignment of the components inside the auto hubs is very important to the proper operation.

So the question is where should I go from here in the repair to the auto hubs? Should I tear them down and then get on the phone to you to tell you what I see? Should I consider them trash now since I've tried to use them with there being a mis-alignment of the internals?

Thanks Much in Advance,
Russell

A. First off Russ, save your money. Calling me and describing what you see is not going to work. I have to be able to see what it is and then I can figure out what needs to be done.

There is a number of special tools required to reassemble the automatic locking hubs correctly. I don't know which manual you used, but it seems like they may not have mentioned that fact.

The inner cam with the cam gear is probably where the problem is. Here is the procedure for setting the cam and cam gear.

10. With transfer lever still in the "2H" position, install inner cam with cam gear facing out.
11. Lower vehicle from hoist, then support lower link with floor jack placing axle in normal position.

Fig. 18 Measuring axle shaft snap ring clearance

12. Install tool J-36836 to axle shaft by tool J-36835-2 or equivalent then measure clearance "t" Fig. 18, between tool and snap ring groove of axle shaft using a feeler gauge.
13. Clearance should be .0039. If clearance is larger than specified, select proper shim to meet specification.
14. Remove tool J-36836 and ensure inner cam stays in place. If inner cam is removed, repeat steps 10-13.

This is where I would suggest looking for the problem.