aluminumpork

I took out the center console, took the button out, looked at it and cleaned it. It seems fine, but still no activity when it's pressed. Are there any specific things you would check?

The button doesn't have any sort of click to it, how about you guys? It is just one fluid in and out.

Thanks

dtompsett

could be a few things....

diff lock control module could be shot... it's the little box under the rear seat that controls vacuum to the rear diff actuator. Mine was toast when I got my first 90q... would apply vacuum to unlock the diff, but wouldn't apply vacuum to lock the diff; one of the solenoids inside was shot.

bad rear diff actuator... could be stuck, rotted out, vacuum leaks, rusted out bracket (if the bracket rusts out, it will just flex rather than apply load to the lock arm).

Verify that the diff lock control under the rear seat works, then go at the actuator under the car.

RootMachine

any idea if the cq has the control module in the same location?

dtompsett

should be under the rear seat bottom.... 1 electrical connector, 3 vacuum lines

Mr.88-80Q

Mine clicks, but the little green light won't go on in the lighted 4 wheel drivetrain display.

dtompsett

I think mine still clicked when I engaged it even though the solenoid was shot. But if it's still good, then start looking for a bad vacuum line at the rear diff lock actuator, or a bad actuator.

On my 4kq, the rear actuator would hold vacuum to unlock it, but wouldn't hold vacuum to lock it... wasn't a vacuum line either. The actuator itself was the problem. I swapped with a known working actuator, and it works fine now. I think this is also the same problem I have on my new red 90q... won't lock either.

Mr.88-80Q

Is this piece easy to remove and repair...i.e. clean it up and getting it moving/working again?

dtompsett

It's not something that starts working with a cleaning. It's also not something that comes off easily, especially if it's on an '88! The entire bracket will be rusted out.

Jack up the back end... crawl under... on the drivers side of the diff you'll see the bracket, vacuum actuator, and the little arm that goes into the rear diff.

With the car running and in neutral, push the diff lock button. (works better with a friend doing it). See if the actuator moves. If it does, then it might just be sticking... help it move (might have to spin a rear wheel to line things up inside). Once it locks, unlock it using the switch in the car. Try and cycle it a few times, and see if this frees it up. If it does, then your set, just try to use it regularly to keep things moving.

If that doesn't work, then you need to figure out why. Could be a bad actuator (leaking vacuum), cut vacuum line, or the bracket it's attached to could be so rotted out that rather than hold the actuator in place while it pushed the lock-arm, the bracket is simply flexing and not applying the pressure to the diff lock-arm.

Mr.88-80Q

It stops raining,snowing, and sleeting....which will be in about 4 months...