My right side headlight motor started the typical "can't push the door open, keeps running when it hits bottom" scenario.
Of course, it's just the three plastic bushings... right? Well, apparently not.

It seems like the worm gear (aka the motor shaft) is slipping on the gear. The odd thing is that the gear doesn't really look worn, to me.
Is it possible that the motor shaft gear is pushing back away from the plastic gear, allowing it to jump? Is it possible that the worm gear is slipping on the motor shaft? (I had always ASSumed that the worm gear was an integral part of the shaft, but I've been surprised before.)
I tightened the screw that holds the shaft, at the bottom of the motor. Not enough to make it bind however. Made essentially no difference.
So... Just order a new gear and be done with it?

What say the experts?

Thanks!

[This message has been edited by Raydar (edited 04-15-2018).]

I have seen the plastic bushing metal housing turn on the gearbox output shaft. Exact symptom you describe, took me a while to catch on to what the culprit was.
The bushing housing is not mechanically pinned or keyed to the output shaft, it's just a force fit or maybe shrunk fit.

The plastic gear? THAT output shaft? Holy crap.
Didn't even think of that. Wow. (Thought I could hear the teeth jumping, when I held the mechanism, but perhaps not.)
The gears are ~$40. That's almost $40 worth of PITA, to "pin" that sucker. Might be worth it for bragging rights, however.

Edit... Brain cramp.
The metal piece holds the output shaft. Duh!
I'll have to look into that.

Thanks!

[This message has been edited by Raydar (edited 04-15-2018).]

It's been a while, but I seem to recall that the output shafts are the same for Gen 1 and Gen 2 headlight motors.
I would need to verify that to be positive.

Don't go to any trouble.
If the shaft is turning, that means it's probably loose enough to be removed. I can epoxy it or stake it, or something.
I think I even have an extra motor, someplace.

The output shaft is knurled and the aluminum piece is probably installed as Joe describes. It would need to be an interference fit, so likely the aluminum portion was heated when it was positioned on the metal shaft. It may have even been cast onto the shaft. Some on here have reported success with drilling and pinning the pieces together and others have reported failure with that process.

I had one that was slipping on the shaft, but it wasn't apparent when trying to twist the two by hand. I had to put the arm onto the end of the shaft in order to get enough leverage to turn the shaft.

Don't "rebuilt" Gen2 motors. Is harder then many claim. You often think you fix them but buying new "tougher" parts moves next breakdown to another "weak" part.
Example: New Delrin pins then normal loads just break the gear and/or the output shaft.
See //www.fiero.nl/forum/Forum2/HTML/128600.html

Cardone have rebuilt and new motors w/ a warranty.

Lift and/or door w/ binding problems won't help any motor...
1. Take apart all of the lift pivots, check/clean all parts, spray metal w/ Dry Teflon then reassemble. If link between motor and HL is riveted and worn find other... see //www.fiero.nl/forum/Forum2/HTML/140693.html

2. Check lift alignment! Lifts are often reinstall poorly and bind against the door and/or hood. Only parts should hit are the door plastic bearings hitting 2 bumps on the lift. Maybe 2 more on the HL trim when door is nearly (~99%) up. Most "short" HL mod remove the bearing points and causes door and/or motor problems.
See //www.fiero.nl/forum/F.../HTML/140521.html#p7

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 04-16-2018).]

The resolution...
The aluminum triangular piece (the one that fits into the gear, along with the plastic bushings) was, indeed, turning on the shaft. (Ya' learn something new every day.)
Fortunately, I had some spare motor pieces that came out of a parts car, so I was able to piece it back together in short order.
Everything is working correctly, now.

Thanks, once again, for everyone's input. Always appreciated.

Certainly you can rebuild and I have done it Its great for a car that is used only occasionally but the Delrin pins that everyone uses does nothing to soften the impact of the mechanism when it slams on and off. The original pins offered some flex so how long the fix will work cannot be determined.
My newest method is to replace the motors with new ones offered by Cardone.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 04-19-2018).]