Getting the Pinion to stay on the motor shaft?

[Thirdgen89GTA]

Anyone have any advice on this "fun" problem? Running 3S or 4S its not a problem. However put 6S on the truck and after about 2-3 minutes of running the pinion will walk itself off the shaft. Thankfully I've been lucky in that each time its done it, it hasn't stripped a spur or pinion. no real wear/tear honestly. Also, my battery tray keeps the pinion mostly on the shaft so it doesn't get lost. An unintended benefit of the way I built the conversion.

I've used globs of blue loctite. Waited 24hrs before it cured. I've replaced the set screw thinking maybe the old one just just not holding.

I've tried with the pinion in both directions.

If I had any red loctite I'd be using that now, but I'll be buying some tomorrow simply because i'm tired of only being able to run 2-3 minutes before having to "fix" the truck.

I had even considering marking where the set screw sits and cutting a tiny indentation in the shaft so the set screw can sit "in" the depression. But I don't want to cut shaft if I don't have to.

If I thought I'd never have to take this motor out of the car ever again I might even JB Weld that thing on there. I just want to play with my new toy, not fix it constantly.