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I've had my old tub style rc10gt since the early 90's. it's been a blast to bash around. After years of abuse I decided to upgrade the stock parts and also use the blue flat chassis. Now with the new os 18cvr and a gpm tranny case, I can't seem to get the gears to mesh correctly. I've tried use the stock tranny case and its the same also. Could it be, the chassis mounting holes are off a bit either the engine mounts or tranny case?? Any suggestions?

I'm not sure it's even possible to use the old black tub mounts on the blue chassis but the blue chassis does require a different engine mount. Have you done that? Next, are the gears not lining up or just not getting close enough?

romulus22 wrote:I'm not sure it's even possible to use the old black tub mounts on the blue chassis but the blue chassis does require a different engine mount. Have you done that? Next, are the gears not lining up or just not getting close enough?

I've purchased the correct mounts for OS pull start. The gears do mesh but when I tighten the screws for the tranny housing, the gears are hard to spin and not centred with each other. From a birds eye view, you can see the gears are off to the left very slightly. If I loosen the tranny screws the gears mesh perfectly. Very weird.

The mesh will change slightly when you tighten down the motor mount screws, you just need to adjust for this before you tighten the screws down. If the mesh gets tighter after you tighten the screws, just leave it a little looser before tightening, then when you tighten the screws down it will be perfect. You just have to play around with it until you find the sweet spot. It's normal.

A good way to hold good gear mesh is to stick a sheet of paper in between the gears. Hold that then tighten. When you pull the paper out your gear mesh should be almost perfect.

Rc10boi wrote: From a birds eye view, you can see the gears are off to the left very slightly. If I loosen the tranny screws the gears mesh perfectly. Very weird.

If I read correctly your issue isn't with the mesh of the teeth it's more the side to side fit of the gears? If so, you can remove or add spacers before the collet to adjust this. I don't remember running any spacers on my gt bitd

Thanks guys for all the advice! Will keep ya posted.

FINALLY!! Engine and tranny gears mesh up perfectly!! Thanks for all the advice. Used each one to set mesh properly!!