Mad Monkey noisy gearbox

[Simion Wabs]

Just finished building the Mad Monkey and installed the Clash 21t brushed motor that came with the kit. Boy is it noisy!! Gear mesh between pinion and slipper gear is spot on. Some questions, answers please...

Is the kit pinion and spur gear .48DP?
Is a noisy gearbox common on Mad Monkey/rat?
Does it eventually "bed in" after some use?
Do I need to pack the gearbox with copious amounts of grease to quieten it down?

Tried to fit a Mtroniks Sensorless Brushless motor but the chassis base interferes with the motor case.

Do you have to remove the whole rear section to install a new motor?
Access to motor screw very restricted.

Cheers in advance

Si
p.s. enjoyed the build

[Robbiejuk]

They are noisier than most other 2wd cars but not excessivley. I if i were you I would take it back apart and check the gears in the gearbox are ok.

Have you ballraced the car? Is the gear box tight if you remove the pinion and spin the spur gear?

No you don't have to take the rear of the car off to change the motor. The lower screw is a bit of a pain to get to, I would advise looking for a ball ended allen wrench as that does make it easier to adjust the screw. For some reason whoever designed the car put provision in to be able to tighten the screw that goes through the motor plate and into the securing block, which personally I have never touched since building the car, but not for the one screw that you will be adjusting the most. You can make the job easier with a bit of drenel work though.

[Simion Wabs]

Thanks Robbie,

yes car is ballraced throughout and gearbox runs smooth without pinion attached (but this is not under loading) so will just have to accept the noisy gearbox I think. I will repack with grease as the grease will supress excessive noise. As for the motor screw, I suspected some work with a dremel might be required .
On another note, the manual gave no guidance on diff settings, so I set it to allow for a small amount of slippage (as i have done for other car diffs) and the diff action felt very smooth before installing so hopefully that is not contributing to the noise.

Cheers
Si

[Robbiejuk]

Originally Posted by Simion Wabs

Thanks Robbie,

yes car is ballraced throughout and gearbox runs smooth without pinion attached (but this is not under loading)

Cheers
Si

Take the pinion off an push across a smooth surface, it should roll for a bit before stopping. If the gearbox is tigth then it won't go very far after you give it a shove.

I suspect the noise could be a badly moulded spur gear or out of tolerance pinion. have you got a different pinion and spur to try?

I never us grease in my gearbox, and if I do it would be one spot of grease on the diff pully and then run through the rest of the gears by turning the layshaft. You don't need much in there.

If the diff is going to make any noise due to slippage it will be a chirping noise. It shouldn't make the car sound like a bag of spanners.

[Tom3012]

Hmmm, odd one... Definately built correctly? Is it a new or second hand car? I would advise ceramic diff balls as a start...

You dont need alot of grease in the diff, i usually just put a small blob in each hole of the diff gear then a smidge on the diff rings, nowhere else...

With it only being noisey when the pinion is meshed i would guess maybe the pinion or spur gear arent right, try a different spur/ pinion and see if theres a difference?

Hope that helps

Tom

[Tom3012]

Beat me to it rob!

[luniemiester]

Assuming you mean the gears I found my box noisy when I built it even with grease. Took it apart cleaned all the grease out and added a few drops of 50wt shock oil, not to much in case it got in the diff but enough to get around the idlers - smooth as silk since and not touched it since (About 8 meetings)

[Gunter]

Personally Simon I would of said it were the gear box it would do it all the time with of without the motor/ pinion connected. Must be the spur/ pinion so change pinion see what happens. If still nothing you sure it's not the motor making the noise? As I've got a motor that clicks as u spin it so could be something similar.

But if u still got a probs at racing tomorrow come see me or Gordy n I'm sure between us we could get it worked out

[chris brown]

Do they come with a 21t motor? I thought thay came with a 23t. I was thinking of buying a 21t as I thought mine was a 23t.

Anyone?

[RogerM]

I hope to be at club for a bit tonight and I'll show you how to set a ball diff properly (might need a quick rebuild in order to be able to do it depending on how you built it!!)

I only ever put one tiny dab of ball diff grease on one gear and sin the box over by hand to distribute it.
NEVER pack gearboxes with grease as the extra drag will cause you all sorts of issues, especially on Gloucester's tiny tiny tiny track!!