Kraton Pinion problems

Caloon

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Hello fellow Kraton owners!! Recently purchased a new Kraton and I've been having a blast with it!!! What a beast! I am however having a few minor issues. I broke a suspension mount so tonight i decided to do my first routine maintenance on this bad boy. After getting the suspension mount in no problem i went outside for a test run, Everything was working great until i brought the car back and started to hear some grinding. Upon looking i noticed that my Pinion gear had moved forward on the motor shaft. So far forward that the Pinion gear was no longer meshing with the spur gear. I ran into a problem while disassembling to repair this issue. One of issues is a hex screw being rounded out in the chassis so i am unable to demount the motor. I'm not sure how to describe my 2nd issue or what happened to my pinion so i have attached a picture for reference. Any advice/helpful information is greatly appreciated!
 

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RC Pimp

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usually that happens when there is not enough thread lock on the grub screw and not tight enough on there.
Regarding the rounded of screw you can cut a straight line into it with dremel tool and use a screwdriver to remove it or get screw extractor kit
 

Caloon

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Appreciate the quick response! Thanks for the info i had no idea. I'm trying the JB Weld/Glue trick for the stripped screw we'll see how that goes. Once i get that screw out then i can work on fixing the pinion and whatnot. Does Arrma have special threads for the screws or can i buy any brand and put them in? Im looking for a new AR722412 but i don't really want to pay 6-8$ for 4 tiny screws.
 

RC Pimp

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Appreciate the quick response! Thanks for the info i had no idea. I'm trying the JB Weld/Glue trick for the stripped screw we'll see how that goes. Once i get that screw out then i can work on fixing the pinion and whatnot.
you might not have too, you should be able to remove the grub screw , clean it in alcohol and push the gear into mesh again and tighten with fresh threadlock
 

Capt_Ron

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Appreciate the quick response! Thanks for the info i had no idea. I'm trying the JB Weld/Glue trick for the stripped screw we'll see how that goes. Once i get that screw out then i can work on fixing the pinion and whatnot. Does Arrma have special threads for the screws or can i buy any brand and put them in? Im looking for a new AR722412 but i don't really want to pay 6-8$ for 4 tiny screws.
They used normal metric screws.
 

Caloon

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you might not have too, you should be able to remove the grub screw , clean it in alcohol and push the gear into mesh again and tighten with fresh threadlock
The grub screw is gone, there is nothing there. Thats why i was so confused and posted that pic LOL. Im due for diff maintenance as well so i really need to get that screw out.
 

Caloon

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Alright got that chassis screw out but now my damn pinion won't come off!? Grrrrr!!! The pinion slides up and down the motor shaft fairly easily but as soon as i get it to the end to take it off it's almost like the pinion is stuck on something and won't come the rest of the way off. Please help! Picture for reference of what im dealing with.
 

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Kauaiguy

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Alright got that chassis screw out but now my damn pinion won't come off!? Grrrrr!!! The pinion slides up and down the motor shaft fairly easily but as soon as i get it to the end to take it off it's almost like the pinion is stuck on something and won't come the rest of the way off. Please help! Picture for reference of what im dealing with.
Probably a burr from spining on the shaft,your best bet is to use a pinion puller( right tool for the job).It might come loose if you use two blade screw drivers to pry equaly at the same time.
 

Caloon

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Probably a burr from spining on the shaft,your best bet is to use a pinion puller( right tool for the job).It might come loose if you use two blade screw drivers to pry equaly at the same time.
Appreciate the info!

Probably a burr from spining on the shaft,your best bet is to use a pinion puller( right tool for the job).It might come loose if you use two blade screw drivers to pry equaly at the same time.
Wow it's really on there! I bent my screwdrivers trying to get it off. Any other ideas without having to buy a pinion puller?
 

Kauaiguy

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Appreciate the info!


Wow it's really on there! I bent my screwdrivers trying to get it off. Any other ideas without having to buy a pinion puller?
Remove the motor from truck,clamp pinion in vise and use a small shaft and tap on the motor shaft till the bugger comes out?
 

Kauaiguy

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From looking at your picture,the grub screw is still in there,the head got wore away by your spur gear as the grub screw backed out.It might be catching on the remaining part.Looks like you could tap a small hex wrench into the hole.The grub screw should be fairly loose as it backed out,see if you can get to come out.Check your spur gear,it might have some tooth decay.
 

Caloon

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From looking at your picture,the grub screw is still in there,the head got wore away by your spur gear as the grub screw backed out.It might be catching on the remaining part.Looks like you could tap a small hex wrench into the hole.The grub screw should be fairly loose as it backed out,see if you can get to come out.Check your spur gear,it might have some tooth decay.
Tried that out. The hex wrench just spins in the hole, doesn't grip anything or move. Spur gear looks good though! Im not sure i have the right size hex, the one i used is to small and the next step up is too big. Im trying all the wrenches that came with the truggy.
 

Kauaiguy

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Tried that out. The hex wrench just spins in the hole, doesn't grip anything or move. Spur gear looks good though! Im not sure i have the right size hex, the one i used is to small and the next step up is too big. Im trying all the wrenches that came with the truggy.
Choices are drill the setscrew out( i would use a left hand drill bit 2.5mm,they rotate in the direction the screw wants to come out,so it usaually gets stuck to the setscrew and comes out.
Pinion puller
Hex screw extractor
Tap something in that you can turn
You may need a new pinion after if the threads get screwed up
 

Caloon

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Choices are drill the setscrew out( i would use a left hand drill bit 2.5mm,they rotate in the direction the screw wants to come out,so it usaually gets stuck to the setscrew and comes out.
Pinion puller
Hex screw extractor
Tap something in that you can turn
You may need a new pinion after if the threads get screwed up
Thank you for all the great tips! I've still got the 14T I got with the Kraton that I'm going to put in. Gonna give those methods a shot tomorrow.
 

Vanning

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Don't forget...the stock motor shaft has a lip at the end of it. The pinions set screw has to be all the way out to clear the lip.

Alright got that chassis screw out but now my damn pinion won't come off!? Grrrrr!!! The pinion slides up and down the motor shaft fairly easily but as soon as i get it to the end to take it off it's almost like the pinion is stuck on something and won't come the rest of the way off. Please help! Picture for reference of what im dealing with.
The motor shaft has a lip at the end of it....your pinion set screw needs to clear it.
 

Caloon

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Appreciate all the helpful info. SUCCESS!! I have removed my motor and center diff to do some maintenance on it and i got my friggin pinion off! The grub screw was still there, I managed to remove it with an easy out. I'll be back on the road in no time!
 

CL-Audio

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Appreciate all the helpful info. SUCCESS!! I have removed my motor and center diff to do some maintenance on it and i got my friggin pinion off! The grub screw was still there, I managed to remove it with an easy out. I'll be back on the road in no time!
What's an easy out??
 

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