Kraton Noise of grinding coming from center or rear area

[Opua]

hi, i have a problem with my kraton v5. the model started making a bad noise after hard braking at maximum speed (54 mph). I have already disassembled the center differential and the rear, checked the gears and it looks fine. I replaced the plastic case with a metal differential case (ARA 220050) but the noise is still there! it comes from the central or rear area, this is what I hear by ear ... the noise starts when I reverse or brake the model, but if I take off the wheels and try to accelerate and in reverse it makes no noise, so only with the wheels mounted , any wheel I have mounted starts the noise! Can anyone help me find a solution? I also replaced the pinion with a 14 teeth but nothing to do. I' haven't check the front diff because i have put about one week ago a new oil (60K) and the gears were ok, moreover as i wrote before this noise of grinding come from the center or rear area.
here a my youtube video where you can ear the noise at minute 1.22 and 2.03

 

[Sandracer_NL]

Could be a stripped ring/input gear. But it’s a matter of elimination. I’d check all three diffs, both internal gears and the ring and input gearsmand the bearings. Could also be a bad motor bearing resulting in play of the motor shaft.

 

[Opua]

Could be a stripped ring/input gear. But it’s a matter of elimination. I’d check all three diffs, both internal gears and the ring and input gearsmand the bearings. Could also be a bad motor bearing resulting in play of the motor shaft.

Hi, if it was the motor shaft bearing, i think that it would have to do it even without the wheels mounted

 

[RcDad23]

Hey the little problem that happen to me and u even can't see it is the pin that hold the gear on diff spur or the other one inside the diff.that breaks and when u move it to take it out is wen u notice is bad.hope this helps.those are not the ones I just tonshow what it is whttps://www.amainhobbies.com/arrma-2.25x9.8mm-pin-6-ara310440/p409430?gclid=CjwKCAjwp9qZBhBkEiwAsYFsb25lFYHAhpQBfUjSOsXCPTtH3Gz9vZTbygeb_3o0B26pbwxA4LBfwBoCI1IQAvD_BwE

 

[Diem Turner]

Hi, if it was the motor shaft bearing, i think that it would have to do it even without the wheels mounted

My guess is it's your front diff since it's most noticeable under braking (all of the weight of the car transfers to the front under braking). I don't think anything is broken in the diff, otherwise you would probably notice the car pulling to one side or the other under acceleration (I would still disassemble it completely just to make sure however; maybe one of the cross pins under the sun gear sheared or something else). I'm just spit balling here. It's the only diff you haven't inspected. That's where I'd go next. My $0.02.

 

[Infraction666]

Sounded like my Kraton

On my Kraton with the front input gear

There is a shim behind the input gear that was beginning to be oval shape
I could not figure out what it's was to begin with,
First when it's snap and broke the input

Here you can hear it to

 

[Opua]

Hey the little problem that happen to me and u even can't see it is the pin that hold the gear on diff spur or the other one inside the diff.that breaks and when u move it to take it out is wen u notice is bad.hope this helps.those are not the ones I just tonshow what it is whttps://www.amainhobbies.com/arrma-2.25x9.8mm-pin-6-ara310440/p409430?gclid=CjwKCAjwp9qZBhBkEiwAsYFsb25lFYHAhpQBfUjSOsXCPTtH3Gz9vZTbygeb_3o0B26pbwxA4LBfwBoCI1IQAvD_BwE

the pin of rear and center diff are both good, i don't know if the front is good. But last week i changed his oil and were good.

My guess is it's your front diff since it's most noticeable under braking (all of the weight of the car transfers to the front under braking). I don't think anything is broken in the diff, otherwise you would probably notice the car pulling to one side or the other under acceleration (I would still disassemble it completely just to make sure however; maybe one of the cross pins under the sun gear sheared or something else). I'm just spit balling here. It's the only diff you haven't inspected. That's where I'd go next. My $0.02.

i'll try to teardown the front. However the input shaft cup sleeve (ARA 310976) have a big clearance, i mean axial and radial clearance. the problem doesn't exist if i turn the model without wheels

 

[Opua]

Update: I replaced the front input gear (it was damaged) and now the noise is almost completely gone, almost because it's always there a bit. I would put extra shim in the front diff using the shim provided by arrma. What do you think about it?

 

[RcDad23]

Just go till almost no movement from rigth to left, hope u fix it and have a happy bashing again,we on the east coast and the temperatures don't help,Have a bless day