Trucks Motor Pinion

Hi guys i'm having some issues with my car. When I crash last time, I had stripped the pinion gear (I had the meshing too tight), but I had noticed as well was the fact that the grub screw had come out.
I finally got it fixed, and went out just in the back yard, drove a couple laps and then suddenly the pinion gear has given way and shot out somewhere, and the hole where the grub screw has become ovalised.
Just a dodgy pinion, or still something with my set up that is wrong?
 

Tony

Staff member
You stripped the pinion? Or the Spur?

And I would bet the pinion just wasn't seated correctly. Get a new one, put it on and use thread locker on it.
 
the Pinion gear ended up stripped.

I was thinking that with my issue last night it was the pinion not sitting properly on the shaft. I will get yet another one and this time i will locktite it onto the motor shaft. I think I have the spacing right now, so I will just have to get the set screw done properly. Just wanted to check my theory before going and destroying another one
 
Hey Tony,
Is there a way of making sure that it is seated properly on the flat of the shaft?
I did also forget locktite last time... my dumb rookie mistake.
Also, when looking at the suspension, general sag of the vehicle, is it the springs that are meant to keep the shock expanded and resist the weight of the truck?
I put new shocks on it, and i suspect the springs might be a touch light
 

Tony

Staff member
To make sure you are on the flat of the shaft, just screw the grub screw down slowly. If you are off center, you will feel the shaft twist so that the grub is sitting on the flat. And yes, blue thread locker is a must on a pinion.

As for the shocks, yes, the springs are what hold the vehicle up, the shock oil is what keeps it from bouncing. With the truck ready to run, you should be able to drop it from a height or aprox 1' (or a half meter, I know, half meter is more than a foot, it will still work) and the drive bones should be level. This also depends on what truck you have as well.
 
Sweet thanks for that Tony. I know I stuffed up the pinion the first time around. Was really annoyed cos I spent a bit of time really making sure that the pinion and spur were lined up properly!
I think I do need heavier springs then... this is sagging under it's own weight. I'll use the OEM springs I think for now. the oil shouldn't be a problem.
Sweet thanks again for the help Tony
 
Is it possible that I've rounded the edges off the motor shaft. Have locktited in the grub screw to secure the motor pinion, but it is still working it's way loose... just trying to work it out...
 

Tony

Staff member
You might want to think about balancing the motor. If it is loosening all the time, it could be because of a harmonic vibration from high rpm.
 
How do I balance a motor?
I'm not sure if I took it out too quickly after putting the motor pinion on. I've since let it cure properly, and was going to try again and see what happened.
But yes you could be right, and if the resonance is making it come out, I will balance the motor.
Will be good to know how to do it.
 
Will youtube it and find out.
Unless we've done it on here somewhere?
Will have to try and do a video of it if I end up doing myself for the website
 
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