Underdrive gear problem

[VTHokie]

Hey all,

I purchased some 43/13 underdrive gears for my Deadbolt and after installing them have some mesh issues. I've searched for solutions but nothing seems to help. Any ideas on how to correct this? So far I've tried removing the gasket and loosening the bearing caps. It's grinding more on one side than the other on the ring.

I've shimmed my mini E-revo before but not sure if I can or what I would need to shim these axles.

[Solitaire]

Make sure the pinion gear is pushed all the way down into the bearing(s). Sometimes it takes a little tap to get it seated properly. I've had several that needed that little extra nudge as some get hung up just enough to create a poor mesh.

[Meatwad]

Agreed, pinion needs to be tapped in slightly better and/or some type of debris keeping a bearing from fully seating.

[VTHokie]

I tore everything apart again and made sure the pinion was as far seated as I could get it. There's still some gear noise. If I unseat the bearing on the gear side it spins freely and sounds perfect. Of course when I put the bearing caps on it seats the ring gear back down and thus returns the grind. Maybe I'm gonna just have to live with it unless anyone has another idea.

On a side note, what's up with these diff cover screw heads constantly stripping? I've gone through 5 of these already. Seems like Axial may have tightened them too much. The heads on 5 of my diff cover screws were partly stripped the first time I took them off. Combine that with my torque taking them off and they're done. What a pain using a needle nose to back out those long screws.

[Solitaire]

Hmmm, never have had a problem with those diff cover bolts. Make sure you're using a decent metric driver and not a SAE one. The replacements don't have to be torqued down...just snug as they are only 2 mil and not a lot of thread depth.

As far as your diff gears...I've had some that aren't quite as smooth as I like, but it's never affected performance.

[TSK]

Check that the heads of the 4 screws that secure the ring gear to the locker isn't contacting the bearing cap.

[VTHokie]

I got it all back together and as close as I could get it. I guess I'm just used to 1:1 gear set-ups. Took it out for test drive and there's definitely some grinding under load but I don't trail ride too much so maybe they'll hold up. Overall though a definite improvement over stock. I'm thinking the machining may be slightly off at this point. I forgot to mention they're the Hot Racing brand and not Axial. Guess it never pays to go cheap but I'm trying to keep my costs down since I can't quit upgrading this rig. It's just so much fun.

I bought the same size Axial diff cover screws for replacements. Maybe I should get some shorter ones like you mentioned Solitaire. It does seem like overkill to be that long. I'm using the 1.5mm allen that came in my Dynamite tool kit I picked up from my LHS.

[VTHokie]

It's definitely gear grindage. I can feel the miss match in gear mesh when I spin the pinion.

[meatmonkey]

I'd suspect the machining of the gears.

Last thing to check would be any burrs/plastic mold imperfection on the mating surfaces of the Ring gear and the plastic carrier that could prevent the gears from running true?

[Calderwood]

The gears hold up a lot better when they are setup "crunchy". If they aren't like that I shim them until they are. I have never stripped the diff cover bolts and I have taken them out a lot. I suspect your driver isn't sharp enough.

[Androtaz]

My od axial gears in my poison spyder do the same thing. doesn't affect its performance a bit.

Originally Posted by Calderwood

The gears hold up a lot better when they are setup "crunchy". If they aren't like that I shim them until they are. I have never stripped the diff cover bolts and I have taken them out a lot. I suspect your driver isn't sharp enough.

[chipgibbs]

This may sound basic but, Make sure the ring gear is on the correct side of the pinion. Be sure the axle is right side up & that the ring gear is on the right, Not left, side of the pinion.

You might also remove the pinion and install the diff w/ ring gear to see if it seats into the bearing carriers correctly and spins freely. Does it spin straight & not osilate / wobble?

[VTHokie]

I'm putting the underdrive gears in the rear if the ring were on the right then the back wheels would try and go backwards when front were trying to go forward. I did test the gears in this configuration though and they mesh perfect.

What's funny is my directions do show both ring gears being installed on the long axle side.

[TSK]

Originally Posted by TheSCorpionKing

Check that the heads of the 4 screws that secure the ring gear to the locker isn't contacting the bearing cap.

Originally Posted by chipgibbs

You might also remove the pinion and install the diff w/ ring gear to see if it seats into the bearing carriers correctly and spins freely. Does it spin straight & not osilate / wobble?

I like this guys suggestion

[VTHokie]

The ring gear screws are good. The assembly is moving freely and doesn't appear to have any wobble. At this point I think it's really just bad machining. Guess I'm running "crunchy".

[Flash178]

A person I crawl with had the same problem with the same gear in his wraith.
Turns out it was a bad set from axial.