[amelko01]

I have an HPI rtr rs4 with a O.S. 12cv-rx. The past two times I have run my car my heavy duty two speed has started out shifting fine, then stopped shifting, then the car has stopped running because the spur gears had some teeth missing, some melted over, and there was no mesh.
Well I replaced the spur gears, loosened the engine mount screws and alligned the mesh correctly, put heavy duty threadlocker on the screws, let it dry, and ran it again. The same thing happened; the two speed was shifting fine at first, then it stopped shifting, then the car wouldn't move when I opened the the throttle. So I pinched the fuel line and took a look at the gears. The spur gears had teeth that were missing and melted and they basically were not meshing at all with the pinion gears. I never had this problem before I got the two-speed, could the problem be caused somehow by it shifting. Any help is appreciated.

[Fafnir]

Figure out where the heat is coming from that is melting the gears. I don't have your car and don't know much about it, but it sounds like a slipper clutch or something is slipping too much and causing the buildup of heat which is melting your gears.

--Chad

[hardcoreONE]

what happens is that some how, the mesh is slipping, and since the teeth arent fully meshing with the other teethk, and they spin faster as you give it more throttle, which rubs on the teeth and melts them and wears them down. there is a similar problem on the old school RC10GT, which is due to rear flexing, or the back of the chassis between the engine and the transmission is too much, causing the mesh to get out of alingment. you are also running a powerful engine, which will cause the back to flex even more. i dont have this car, either, but i would try looking for braces for the rear end, anything that will make the back end of the chassis stiffer. also, see if there is any kind of motor mount that connects the engine mount to the transmisson. this is what trinity made for the GT, and it fixed the problem. this what i think it could be.

[amelko01]

thanks guys, I'll keep you updated on how things go.

[raderrustler]

Remember that the little os 12 cv-rx is a true 1hp and twists at 31k. trying to find heat source will be hard but make sure that the motor is not shredding the gears when shifting and then melting, hope it helps.

[associatedGTguy]

make sure your chassis isnt flexing...If it flexes too much it will cause improper gear mesh. I had that problem with my older style gt tub chassis when i installed a os hyper. i'm not real familiar with on road cars ..but see how much your chassis flexes