t-maxx gears stripping...ahhh

[bashmaster]

hey guys
my delima:

i got an epic .18 in a t-maxx with a stock drive train.
the sliders arent twisting at all, but i havent leaned out all the way... but while i was BREAKING IT IN the power from this motor stripped the primary out 2 twice in under 15 mins of run time (heat cycle breakin only) am i doing something very wrong with my gears or do plastic ones just suck? they did fine with my old trx .15 and they are fine on my bros trx2.5 and the epic is only rated at 38% more power (alot i guess) but i need a fix for this.
i dont think i can go full bombproof tranny (no job, no money) but if i only replace some gears with metal will that just make me strip the plastics left?
thnx

 

[El Pirata]

Sounds like something might be defective in the tranny.

 

[bashmaster]

i dont think theres anything wrong with the tranny because it ran fine without any work to it atall when i had the trx.15 in the truck, when i got the epic i had problem start up. i had never cracked the tranny case open till the primary when out the frist time.

 

[SkyMaxx]

When you say primary, do you mean the large gear that is external to the tranny casing? If so, the proper term for it in the RC world is the spur gear (not that primary is wrong).

If you are stripping the spur gear with that engine, you may need to consider two things:
1. Your setting on the slipper clutch. Is the slipper clutch nut tightened down too far? If so, the slipper is not being allowed to do its job. The end result is a gear that gets over stressed by the sudden onset of rpms from the clutch bell and viola you strip the spur gear.
2. Your mesh setting might not be quite right or is being affected by something when your running your truck (for example chassis flex or a bent chassis).

The solution to the first possible problem is simple enough. Loosen the slipper clutch nut. A good starting point is to tighten it all the way down and back it off about a 1/4 of a turn. If you are still having problems, back it off another 1/4 turn. Keep doing this until you see the performance you desire and no damage to the spur.

The solutions to the second possible problem can be either easy (ie make certain you have set your mesh properly and have used loctite on the engine mount screws to ensure the engine doesn't slide away from the centerline of the chassis) to really complicated depending on what is causing the chassis flex or other problems affecting gear mesh. As you can imagine, the cost for the simple solution is rather cheap; the complicated solution might cost you more depending on what you may need to replace.

Now, if you are referring to the primary gear inside the tranny casing...you have another issue all together. BUT it could easily be related to your slipper clutch set up. If the slipper is not allowing for a gradual loading of the tranny, then you can easily strip out the tranny gears by applying too much power too rapidly.

 

[bashmaster]

lol i know what a spur gear is. imreferring to the primary in the tranny case

 

[olds97_lss]

I didn't ruin any of those until around my 3rd quart with a 21. Then I went through two of them in a weekend.

I'd suggest getting the replacement for just that gear from RRP. It's the smaller gears in the trans which means there's less plastic/nylon to handle the torque of the engine. The 2 speed gears with the shifting mechanism in them are larger and less likely to break. They are bigger around and can disipate the torque better.

 

[bashmaster]

ok thanx

so get a metal primary?(dang gears are expensive)

 

[olds97_lss]

Yeah they are. But that one in particular will last a long time since the gears it runs with are plastic/nylon. I would venture to guess that that gear running with the plastic/nylon on the two speed will last forever.

 

[StrechM]

RRP, Hardcore and and Dynamite make the gear sets you are looking for.

 

[SkyMaxx]

Originally posted by bashmaster
lol i know what a spur gear is. imreferring to the primary in the tranny case

Sorry about that. Just making certain.