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saju_nyc

Vintage fox gear box

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So I have been restoring my 30 year old fox these last few months (new chasis, ESC, wheels, tires, a couple of suspension arms)  and I finally thought I got it going. I have a 30 year old brushed Le Mans 240st (nothing fancy) and today when I took it out for a run it sounded like the gears were stripping. Sounded like someone driving a bad stick shift. 
How do I know if it’s the gears or drive shaft? When I turn the rear wheel there is about a 45 degree slack before the other wheel kicks in and turns the opposite way. 
Just bumped about the new issue!!

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Hi saju_nyc

When you turn the other rear wheel, is there te same slack?

Did you check the bevel gears?

 

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[1]  Check if the motor's pinion is securely tightened against the cut plane of the motor axle.  It seems basic, but I got some ebay deals where this wasn't properly done.  While you are at it, make sure the spacing plate is in the right position.  

[2]  Just undo one of the pins holding an A-arm, and pull out the drive shaft.  Hold both ends, and turn to see if they are not loose.  If those Octagonal dogbones are gone, you may have to get Novafox drive cups and dogbones. 

 

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On 10/8/2018 at 7:19 AM, Juggular said:

[2]  Just undo one of the pins holding an A-arm, and pull out the drive shaft.  Hold both ends, and turn to see if they are not loose.  If those Octagonal dogbones are gone, you may have to get Novafox drive cups and dogbones. 

You won't be able to pull the driveshaft out, as it's clipped into the gearbox casing from the inside. The original driveshafts do wear out though - mine had worn out its second set when it got retired to the loft back in the very early 90s - it's now come out of hibernation this year and is running on Novafox drive cups and dogbones as said.

If it's the driveshafts, you should be able to tell easily enough though without any dismantling. On mine when they went, the car would get stuck not moving and making the kind of noise you describe. Looking at the driveshafts, you could see the gearbox end turning and the wheel not turning. In my case it was the outer joints that failed, so the driveshaft itself was turning but the wheels weren't. Putting the suspension on its lowest setting (to get the driveshafts as straight as possible) and pushing the shaft into the failed cup (i.e. taking all the slack up in that direction) would get it working again for a couple of minutes until I went over another big bump or whatever!

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I got a fox also. I have fineshed a half restore. Yeah the gears in the fox are tricky. I got new nova gears in the original gear box. It works fine but you have to keep the original gear box if you have the original type axles. The nova fox gear box has some structural changes.

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19 hours ago, Ethan12345 said:

I got a fox also. I have fineshed a half restore. Yeah the gears in the fox are tricky. I got new nova gears in the original gear box. It works fine but you have to keep the original gear box if you have the original type axles. The nova fox gear box has some structural changes.

The NovaFox gearbox casing is different, but it's just that the driveshaft output bearings have a slightly deeper recess to make space for a thicker "E" clip holding the driveshafts in, rather than the tiny fiddly "C" clip of the original. As long as you only use E clips with NovaFox gearbox cases or C clips with vintage Fox gearbox cases, you can mix and match cases, driveshafts and gears. I've got an original gearbox with NovaFox driveshafts in mine - I just reused the old C clips and it was fine.

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