4x4 shift motor shakes..

[Shadow91]

Okay, so I just went through and cleaned the shift motor on my 93 Ex. Took the two wires, yellow and orange, and ran them on a 12v battery and it turned over very easily and smooth, both directions, without an issue. So I go and put it in my truck.. mount everything, hit the button and.... nothing! So I had a friend hit the button while I looked at it.. and it was trying to move, and you could hear it sorta moving, but still nothing. So then I took off the motor off the transfercase and held it while he hit the button, and the motor just kicked, and sorta twitched like it was binded up and didn't want to free spin. It just kept kicking and not wanting to spin.. what's going on?!?

 

[DeRocha]

When you cleaned the motor did you run it with the geared position selector removed? Did you replace the stop bushing?

 

[Shadow91]

I only removed the actual motor.. never messed with the circut board at all. Just cleaned the brushes witch were pitch black and so that's all I though would be the issue..

 

[DeRocha]

I only removed the actual motor.. never messed with the circut board at all. Just cleaned the brushes witch were pitch black and so that's all I though would be the issue..

The worm gear on the shift motor puts out a lot of torque (and can jam against the stop if you didn't stop giving it power). In normal operation the circuit board on the geared sensor acts like a switch and cuts power to the motor when it reaches each position (2H, 4H, 4L).

If you ran the motor (off the T-case) how did you know when to stop giving it power? And did the shift motor bolts line up when you installed the motor?

Geared Position sensor

 

[Shadow91]

How does the motor ground? Everyone that i have talked to locally has said that it sounds like a bad ground?

 

[DeRocha]

How does the motor ground? Everyone that i have talked to locally has said that it sounds like a bad ground?

The metal case of the motor contacts the metal case of the T-Case which is connected to the frame through the multiple bolts and a ground strap or two..

 

[Shadow91]

I actually fixed it last night. The whole time... Just the dang bushing! Works like a charm now. Thanks for all the help!

 

[DeRocha]

I actually fixed it last night. The whole time... Just the dang bushing! Works like a charm now. Thanks for all the help!

Glad to hear you back into 4x4 9 times out of 10 problems with the electronic 4x4 system are caused by the stop bushing. If the bolts come out easily and aren't too rusted then its a pretty quick fix..