Ratcheting noise on my Nitro RC after backyard jump

[hueyc586]

Hi Nitro RCers,

I was out bashing in my yard and having a blast doing some jumps. One of the jumps went sideways and after that my RedCat XTR was making ratcheting noise and wheels wouldn't spin, hear the engine rpm go high when increase throttle on remote but wheels not spinning. Any thoughts on what went wrong or need to be replaced? I am thinking the clutch but not 100% sure... please see video attached. Uploaded U-tube short video click here -> XTR ratcheting noise, XTR noise clip 2.

 

[largaines]

Sounds like a gear out of alignment, I’ve never torn one of those apart but I’ve wrecked a trans pinion gear and that’s the sound it made.

 

[CertifiedMike]

Sounds like the gear mesh... check your motor.
Hopefully its not intermal in the trans.

 

[hueyc586]

Sounds like a gear out of alignment, I’ve never torn one of those apart but I’ve wrecked a trans pinion gear and that’s the sound it made.

Yeah, I've took a closer look and several teeth missing from the spur gear. Not sure what caused this but suspect maybe engine screws bottom plate got loose and mesh gear alignment was off. I've been using the paper method when aligning the pinion and spur gears when seating things back in place. As long as gears create ridge but not poke through, I am good and rotate smoothly. I am not sure if that's a tried and true method but work on my other vehicles. Is that a good practice?

I am trying to find video how to replace Spur gear and proper alignment, any recommendations? I was thinking replacing pinion as well but it looks ok. Parts so hard to find but order directly from RedCat Racing and luckily was able to get them on clearance. The pinion gear 16T said for XTE so hope it will be ok.

 

[hueyc586]

Sounds like the gear mesh... check your motor.
Hopefully it's not intermal in the

Sounds like the gear mesh... check your motor.
Hopefully its not intermal in the trans.

yeah Spur gear, praying nothing else broke... wheels weren't spinning just high rpm when this happened..

 

[hueyc586]

Sounds like the gear mesh... check your motor.
Hopefully its not intermal in the trans.

replacing spur gear isn't too bad right? Appears to be attached to differential and front is brake pad assy. Thinking removing rear axle and wheel get access to the 2 hex screw that holds the brake assy get to spur gear. Not going to touch Pinion, looks fine nothing missing. see pic

 

[hueyc586]

I've disassembled mesh gear / Transmission assy on vehicle but I can't figure out how to remove the Spur gear. Spur gear sandwich by nut in front and smaller oval gear on rear which goes into the trans housing. I don't see any grub screw on either end to loosen and remove spur gear. How to get that nut off front side? Puzzled! see pictures

 

[Littlemotor]

I've disassembled mesh gear / Transmission assy on vehicle but I can't figure out how to remove the Spur gear. Spur gear sandwich by nut in front and smaller oval gear on rear which goes into the trans housing. I don't see any grub screw on either end to loosen and remove spur gear. How to get that nut off front side? Puzzled! see pictures

View attachment 220051

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Simply pull the sun gear off of the outdrive that passes through the center of the spur gear. Then slide the drive pin out of the outdrive, remove the outdrive cup, the o-ring seal, and you’re disassembled.

 

[CertifiedMike]

Nice job chunking that gear!

 

[hueyc586]

Simply pull the sun gear off of the outdrive that passes through the center of the spur gear. Then slide the drive pin out of the outdrive, remove the outdrive cup, the o-ring seal, and you’re disassembled.

got it off, thanks for your help. Man, I am doing this for first time and it's nerve reckoning making sure not screwing anything up. Love this forum, so much support and love for this hobby.

 

[hueyc586]

Got the sun gear off, not too bad and remove shaft pin, assy comes apart. thanks for help! now waiting to new spur gear to arrive, will update once installed.

Nice job chunking that gear!

thanks Mike! I try to be careful since there's no instructions how to do this for this vehicle

 

[CertifiedMike]

Have you looked for exploded views or any extra lit. Rcscrapyard.net is a good source for lit.
I don't own this truck so I can only speculate on disassembly proceedures.
Usually theres a cross pin in output shaft. It will be behind that gear.
In your pics, it almost looks like there is a snap ring that holds your gear in place.
Better pics from straight on might help.
I have seen set ups with grub set screws in the sides of the drive cups too. Loosen that screw, slide the drive cup off and the gear and shaft slide out of the gear.
My phone is older than most ppl's rc cars so screen isn't the best. Maybe someone can offer direct experience or at least has a clearer view.

 

[hueyc586]

Have you looked for exploded views or any extra lit. Rcscrapyard.net is a good source for lit.
I don't own this truck so I can only speculate on disassembly proceedures.
Usually theres a cross pin in output shaft. It will be behind that gear.
In your pics, it almost looks like there is a snap ring that holds your gear in place.
Better pics from straight on might help.
I have seen set ups with grub set screws in the sides of the drive cups too. Loosen that screw, slide the drive cup off and the gear and shaft slide out of the gear.
My phone is older than most ppl's rc cars so screen isn't the best. Maybe someone can offer direct experience or at least has a clearer view.

Have you looked for exploded views or any extra lit. Rcscrapyard.net is a good source for lit.
I don't own this truck so I can only speculate on disassembly proceedures.
Usually theres a cross pin in output shaft. It will be behind that gear.
In your pics, it almost looks like there is a snap ring that holds your gear in place.
Better pics from straight on might help.
I have seen set ups with grub set screws in the sides of the drive cups too. Loosen that screw, slide the drive cup off and the gear and shaft slide out of the gear.
My phone is older than most ppl's rc cars so screen isn't the best. Maybe someone can offer direct experience or at least has a clearer view.

littlemotor reply was very helpful., i didn't realize the sun gear just slides off with some effort and the cross pin you mentioned exposed. That just slides out and everything is good. Should i grease the sun gear before reinstall? If so any recommendation on type of lubricant?

 

[hueyc586]

Have you looked for exploded views or any extra lit. Rcscrapyard.net is a good source for lit.
I don't own this truck so I can only speculate on disassembly proceedures.
Usually theres a cross pin in output shaft. It will be behind that gear.
In your pics, it almost looks like there is a snap ring that holds your gear in place.
Better pics from straight on might help.
I have seen set ups with grub set screws in the sides of the drive cups too. Loosen that screw, slide the drive cup off and the gear and shaft slide out of the gear.
My phone is older than most ppl's rc cars so screen isn't the best. Maybe someone can offer direct experience or at least has a clearer view.

I appreciate your response. I can appreciate older style phone . Yeah, technology has come a long way with screen resolution on those new Iphones, lol.

 

[Littlemotor]

You’ll want to fill the entire differential with silicone oil prior to reassembly.

 

[CertifiedMike]

My older phone is throwing a fit.
Did to find a manual yet? Any info about a starting point for what weight oil to put in there?
Nice job with the diff. @Littlemotor
Is a pretty smart cookie!

 

[Littlemotor]

I’d definitely tear down all three diffs, and start with 7k-7k-3k; Front, center, rear. Should be a good baseline imo with a 4gear diff. Make sure everything is clean prior to reassembly-let alone; adding fluid. Then carefully reassemble, making sure to not overtighten diff cup screws from spur, and ring gears to diff cups. Tighten in a criss-cross sequence, and evenly. I’d bet money they’re all close to empty, and you’ll absolutely overheat the entire differential, and destroy the gears driving like that.

I’d also remove the rest of the center diff stand, and work on it as an assembly on the bench. Much easier, and it’s how they’re designed to be worked on. You’ll actually gain a better idea of what’s going on, and how it needs to be to function properly. -same with the front and rear.

Good luck. There are several video’s available on YT by Adam Drake, and Ryan Lutz that will translate right over from race grade kit buggies, to your Redcat.

Good luck, and don’t get stressed out with it. It’s only nuts and bolts, and you’re not trying to send it into outer space.

 

[hueyc586]

My older phone is throwing a fit.
Did to find a manual yet? Any info about a starting point for what weight oil to put in there?
Nice job with the diff. @Littlemotor
Is a pretty smart cookie!

he knows his nitro rc stuff for sure! I am still waiting for spur gear to arrive from Redcat racing out in AZ. Hopefully, it'll be here next week and find some quiet time to put back together.

 

[hueyc586]

You’ll want to fill the entire differential with silicone oil prior to reassembly.

any particular weight or can i get any silicon oil from Home depot, Ace or Autozone? I see stuff specifically for RC from Losi small bottle but pricey, not sure if necessary. Would this be ok to use https://a.co/d/2NFlASi from amazon.

 

[CertifiedMike]

You want to be using R/C specific silicon oil.
The stuff for cars is anything but pure oil.
I was able to find some bulk oil on ebay. It was 100% oil, not listed as 'for anything' but not approved for human use (implants I assume)
It works perfectly fine.
Microlubol I think.
I can't open the link to tell you about the one you picked out. (my phone, not your link)
"definitely tear down all three diffs, and start with 7k-7k-3k; Front, center, rear. Should be a good baseline imo with a 4gear diff. Make sure everything is clean prior to reassembly-let alone; adding fluid. Then carefully reassemble, making sure to not overtighten diff cup screws from spur, and ring gears to diff cups. Tighten in a criss-cross sequence, and evenly. I’d bet money they’re all close to empty, and you’ll absolutely overheat the entire differential, and destroy the gears driving like that." @Littlemotor

So 7k-7k-3k; Front, center, rear.