I hate my XMaxx - Spur/Pinion Help

[MiamiRC]

One thing I’ve done in the past is to mark the spot where the grub screw touches the shaft, and using a small drill bit, drill a shallow divot into the shaft. Then, a drop of red loctite into the divot, and tighten down the grub screw. Works great, but can be an absolute bear to get the pinion off if you need to lol.

Did you switch to a pointed grub screw? One I have now is flat. I like this idea. If it never comes off again I can live with that....

 

[Sandracer_NL]

Apart from what has been said by others, have you checked your motor bearings? Chances are less likely than what the others suggested, but you never know.

 

[Xjeepguy]

Did you switch to a pointed grub screw? One I have now is flat. I like this idea. If it never comes off again I can live with that....

Yep. Sure did.

 

[MiamiRC]

Apart from what has been said by others, have you checked your motor bearings? Chances are less likely than what the others suggested, but you never know.

Hadn't thought of that. Great idea and would have been an easy fix. Sadly I pulled the motor and they are fine.

This is how I ultimately fixed the issue. View attachment 337597

Will those work with stock motor?

 

[razorrc]

If you're having problems with the stock motor, something with your installation technique is wrong or something in the truck is broken. Putting globs of red loctite or spending hundreds on aluminum is not the answer. I run the truck with the stock electronics doing big air and never have the pinion come loose.

 

[MiamiRC]

If you're having problems with the stock motor, something with your installation technique is wrong or something in the truck is broken. Putting globs of red loctite or spending hundreds on aluminum is not the answer. I run the truck with the stock electronics doing big air and never have the pinion come loose.

I would love either of those to be the answer. I mean on the install what is there really to it to screw up? Cush drive is stock and shaft isn't noticeably bent. Changing the spur is three screws. Both bearings are present. Motor shaft seems ok. Opened up the motor today and the bearings are fine in there. I would love for it to have been a bearing failure. I've set the mesh both with and without the pins. Without using a piece of paper between the gears. Same way I set it with all my Arrmas. Very slight bit of play. It does certainly seem off like something could be broken in the truck but what could it be? Maybe something wrong causing vibration in the motor? I was thinking vibration is maybe shaking it loose but it isn't obvious and I don't know how I'd verify that without swapping out the motor. Seems unlikely (but maybe I'm dumb) that something downstream in the diffs would cause this problem. Where would you look next?

P.S. Love your channel and am subscribed!

 

[Frumba57]

I’m running 18\50 which certainly isn’t crazy. What are you running?

Well, I was using the pins with the stock motor mount but the mesh wasn't right with the Hot Racing one so now I'm just setting it manually. Basically I've done it both ways and doesn't seem to matter.

Running the PL Mashers which probably isn't helping but I just can't with the stock tires which are absolute crap and just blow up constantly.

This is diabolical. I love it. I'm going to superheat that MoFo before I crank it down. Definitely worth a try.

I'm using the stock washers but with the HR motor mount I'm blue loctiting those in. I haven't reallly had an issue with them coming loose but I had that same thought.

Haha, that kind of answer is exactly why I didn't post in the Traxxas forums! Bunch of cotton headed ninny muggins over there.

Red 271 liquid

Been trying to avoid that expense but If I go to a new HW setup I'm definitely going Mod 1.5. Thanks

Just did this to my used XMAXX. Came with paddles. Had to get this rig to flip in the air like my O8S.

It could just be me, but it looked noticeably slow as well. Doesn't seem to have the same oomph as the K8/O8. Which could also contribute to its lackluster performance in the air!
HW EZRUN really woke the truck up. The 1.5 mod comes with a beefy 3mm grub!

 

[Hop79Xmaxx s8]

My set screw for the pinion stays in place but I've just been burning through set screws as the bottom just shaves off. What is the strongest set screw I can get for my 8s X-Maxx that willnt shave the bottom of it. I'm running 18/50 gears at the moment and not sure if I just need to change that setup. Much appreciated for any help on this and Thank you!

 

[MiamiRC]

My set screw for the pinion stays in place but I've just been burning through set screws as the bottom just shaves off. What is the strongest set screw I can get for my 8s X-Maxx that willnt shave the bottom of it. I'm running 18/50 gears at the moment and not sure if I just need to change that setup. Much appreciated for any help on this and Thank you!

I could never keep a pinion on the stock motor shaft. Tried a bunch of different ones. Replaced the motor shaft, spur, nothing made a difference. Tried everything recommended in this thread. Took the motor apart and bearings were fine. Pulled the diffs. Fine. I think what happened is the motor shaft got slightly bent or something in the motor was slightly off and there was a vibration that just kept working the pinion loose no matter what. In any event I finally just gave up on it and scrapped the Traxxas electronics. HW Max 6, 1100kv motor, M2C motor mount and mod 1.5 gears. No issues since then and the power difference is night and day. Just an absolute beast now. So not a cheap solution but it was that or I was just going to sell the thing because it was unusable. So consider if nothing else works you may just have a bad motor.