Problems with Pinion/Spur gears (keep destroying them) **VIDEO Included**

[Xmaxximum]

I have had my Xmaxx since day one....

I have a Max 6 Hobbywing ESC Running Twin 8400 Traxxas Batteries (6S) and I have the punch setting on my ESC on the lowest setting (Punch Setting of 1)

The rest of the truck is pretty much stock, minus the Traxxas Spiral Diff. gears.

18/50 gearing...
I am running a Traxxas 18T Pinion gear with a HotRacing 50t STEEL Spur gear. (Pin "G" on the Traxxas pin selector)

I installed a brand new 50T Steel Hot Racing Spur with a brand new Traxxas 18T Pinion and went for a drive...

After exactly 15 minutes of driving this is what my Spur/Pinion look like: (Watch the entire video please)

https://www.youtube.com/watch?v=XqpCIQHtKmw

I have small chips in my gears in random various locations.



What can cause this?

I am using a brand new Traxxas Spur gear shaft, with brand new slipper clutch steel center bearing, and 2 new shaft support bearings as well. These all have only 15 minutes on them too as I installed them at the same time as the pinion and spur gear.

Is this a cause for concern or is it somewhat normal?

There is NO DEBRIS in the gear area, and I do run with the gear cover ON the truck.

The truck runs great other than this... The motor is tight, and the 4 bolts to the grey cover are tight (not over torqued or stripped)

Edit: Slipper clutch is COMPLETELY locked down. If I loosen it even a little to allow it to slip the nut with back off within a few minutes, extremely annoying... (Its even double nutted)

[rizz0d]

that's odd. looks like you have excessive play with the slipper/bearing/shaft assembly. mine has some play too, but not like that. has the assembly ever been overheated? think maybe the upper/lower bulkheads are wopped out where the bearings sit?

as far as the chunks missing, something has to be getting in there to do.

[atom3624]

Agreed - too much play on the slipper and between the spur and pinion.
Check the bearings are OK - you said it's free-running when in operation, but that much play isn't normal.

Al.

[Xmaxximum]

that's odd. looks like you have excessive play with the slipper/bearing/shaft assembly. mine has some play too, but not like that. has the assembly ever been overheated? think maybe the upper/lower bulkheads are wopped out where the bearings sit?

as far as the chunks missing, something has to be getting in there to do.

Yes it has definitely been overheated before.
I'll go ahead and order it!

[Need|4|Pede]

The gouge in the pinion will keep eating spur gears, so you'll need to replace the pinion. It's possible that there was some debris in there that caught in the gears and was pulverized. Or maybe the new pinion from hot racing had that defect from the get go? I've heard of a few issues with hot racing quality before.

[Xmaxximum]

The gouge in the pinion will keep eating spur gears, so you'll need to replace the pinion. It's possible that there was some debris in there that caught in the gears and was pulverized. Or maybe the new pinion from hot racing had that defect from the get go? I've heard of a few issues with hot racing quality before.

The gouge is new. The pinion and spur were installed at the same time (15 minutes of run time on them)

So last night I replaced that ENTIRE motor bulkhead as stated above. It did not resolve my free play problem in the spur shaft assembly (as seen in the video link above in the original post)

So now what I have new:
*spur gear shaft
*new shaft bearings
*new slipper clutch center steel bearing
*new motor bulkhead

**I do tighten all bolts in a Criss cross pattern and I do not overtightened the bolts.**

What needs to be replaced next to get rid of this Freeplay?!

[atom3624]

OK, silly question, but are the bearings the correct width?
Could be a little narrow, causing the free play ... possibly.

Al.

[Xmaxximum]

OK, silly question, but are the bearings the correct width?
Could be a little narrow, causing the free play ... possibly.

Al.

I just bought some more of the 5180 bearings (6x13x5) and will try again... They are only $5.00...

I also bought a slipper clutch complete assembly because I'm out of any other ideas unless someone else has any input????

[rizz0d]

so with basically everything in that area brand new, it's still chewing itself up?
not much left to change, is the motor shaft tight? is there any play in the motor shaft? motor bearings okay?

[atom3624]

Have the correct mounting points been selected for the motor mount pin location?

Al.

[Xmaxximum]

so with basically everything in that area brand new, it's still chewing itself up?
not much left to change, is the motor shaft tight? is there any play in the motor shaft? motor bearings okay?

18/50 gearing (Pin G) is selected.

And yes still chewing itself up, with both gears being steel. Very expensive when it happens because it keeps happening over and over...

Motor does have a little bit of play in the shaft, I can feel side to side movement almost not visible but you can definitely feel it with your hands... How can I repair that? (New motor?) Or is there an adjustment?

[suburbazine]

If you've overheated it on the stock motor, pull the motor out and check that the shaft bearing didn't soften the endbell and develop free play.

[wyatt333]

Are you sure that there isn't a spacer missing, I don't own one of these yet but the slash 4x4 differentials have a spacer where the drive hub gear comes out. Sorry I don't know all the technical terms for the parts so I don't know If I explained that right.

Sent from my SM-G900V using Tapatalk

[Xmaxximum]

Definitely no spacer missing.

I ended up taking apart my buddies Xmaxx and his truck has IDENTICAL movement in the spur gear assembly.
You visually couldn't tell the 2 apart, except he has literally never had a spur gear problem.

I ended up putting a VERY thin washer at the end of the spur gear assembly (the shaft end furthest away from the spur gear) which literally took up 90%+ of the Freeplay seen in the video in the original post.

(It does not bind, still allows a lot of movement and room for heat expansion.)

3 battery packs zero problems since!

Pulled the spur gear cover and zero wear! Sweet!

[Albie72]

I had a problem when I switched my spur gear.the problem was u have to make sure the plastic clip on the motor mount is in right when u put the motor back in

[Xmaxximum]

I had a problem when I switched my spur gear.the problem was u have to make sure the plastic clip on the motor mount is in right when u put the motor back in

Unfortunately, it is in the proper spot.
I know what your talking about, because if the motor plastic tab isn't in that groove it will also have a repetitive clicking noise.