Typhon Typhon 3S - Grinding when accelerating

[Heinz]

Hi everyone

After a bashing session at a skatepark I noticed something is grinding on the car. No serious air or extreme stunts were pulled. I wasn't sending it duperbash style

I took it apart to check the motor, rear and front diffs (took the opportunity to re-grease them as there looking pretty dry!) and checked the drive shaft too. I could not see any damage/warping on any of those components.

I've got a video below where you can clearly hear the horrible noise when you throttle. I only got the car in May this year.

I'm a bit baffled as to what is going on.

 

[Tex Koder]

Hi everyone

After a bashing session at a skatepark I noticed something is grinding on the car. No serious air or extreme stunts were pulled. I wasn't sending it duperbash style

I took it apart to check the motor, rear and front diffs (took the opportunity to re-grease them as there looking pretty dry!) and checked the drive shaft too. I could not see any damage/warping on any of those components.

I've got a video below where you can clearly hear the horrible noise when you throttle. I only got the car in May this year.

I'm a bit baffled as to what is going on.

Sounds like some tooths are slipping against the diff to me..

Did any tooth get stripped / chipped? Missing?



Here's an extreme example..
I stripped/ground down just about all the tooths on the diff.
Was Bashing a bit Too hard

Eventually the "funny noises" stopped on its own.. Awesome! I thought, it self fixed.
But Hey what's wrong with my rig.. Only the front wheels was getting power....

Oooppsy..

 

[Hector_Fisher]

That's definitely gear related. Either slippage or like missing teeth or something.

Based on my personal experience, I'd say it's the rear diff. Those tend to let go first. Next would be the spur gear on the slipper clutch. It's possible the motor mount got bent and is causing mesh issues.

I know you said you checked the rear diff, and i'm not doubting you did. But that has the exact same sound as a rear diff letting go that has happened to me plenty of times. It's worth a much closer inspection.

 

[Heinz]

Sounds like some tooths are slipping against the diff to me..

Did any tooth get stripped / chipped? Missing?



Here's an extreme example..
I stripped/ground down just about all the tooths on the diff.
Was Bashing a bit Too hard
View attachment 318849

Eventually the "funny noises" stopped on its own.. Awesome! I thought, it self fixed.
But Hey what's wrong with my rig.. Only the front wheels was getting power....

Oooppsy..

Mine didn't look anything like that! It is all intact.

That's definitely gear related. Either slippage or like missing teeth or something.

Based on my personal experience, I'd say it's the rear diff. Those tend to let go first. Next would be the spur gear on the slipper clutch. It's possible the motor mount got bent and is causing mesh issues.

I know you said you checked the rear diff, and i'm not doubting you did. But that has the exact same sound as a rear diff letting go that has happened to me plenty of times. It's worth a much closer inspection.

You may very well be correct. My thoughts were "it must be the rear diff" as that is where the noise is coming from.

I will dismantle it again and inspect everything a bit closer, thank you.

 

[Tex Koder]

Here's what a healthy diff gears look like >>

 

[Sandracer_NL]

My guess too is the (most likely) rear diff: input gear/crown gear skipping a tooth on heavy throttle. Check (by eye or caliper) is one or more teeth are smaller than other, as you most likely ground of a bit.

 

[Heinz]

Here's what a healthy diff gears looks like >>
View attachment 318852

This was the first time I opened the diffs and mine looks like that but I will be inspecting it again as per Hector_Fisher's suggestion.

 

[Tex Koder]

Mine didn't look anything like that! It is all intact.

I my very well be correct. My thoughts were "it must be the rear diff" as that is where the noise is coming from.

I will dismantle it again and inspect everything a bit closer, thank you.

Yeah..
That got a little Beat up ,for sure..

I gave it the ol' Toothless treatment.
Need to go to the dentist..

 

[Sheed85]

Here's what a healthy diff gears look like >>
View attachment 318852

What about the input gear ( the smaller gear that mates with the gear pictured?) For me it was that smaller I put gear that needed replacing only.

 

[Tex Koder]

What about the input gear ( the smaller gear that mates with the gear pictured?) For me it was that smaller I put gear that needed replacing only.

Input gear looked okay.. which is kind of odd to me..
I would have imagined it to be ground up in some way also ,but nope.

 

[Sheed85]

Input gear looked okay.. which is kind of odd to me..
I would have imagined it to be ground up in some way also ,but nope.

I thought you were the OP, haha my bad. Meant for OP, but for me the input gear was the only thing that needed replacing, and it desperately needed diff fluid both F/R

 

[SrC]

That's definitely gear related. Either slippage or like missing teeth or something.

Based on my personal experience, I'd say it's the rear diff. Those tend to let go first. Next would be the spur gear on the slipper clutch. It's possible the motor mount got bent and is causing mesh issues.

I know you said you checked the rear diff, and i'm not doubting you did. But that has the exact same sound as a rear diff letting go that has happened to me plenty of times. It's worth a much closer inspection.

+1
Yeah usually the rear diff goes out first. Also need to Open up the diff completely , both front and rear diffs. Clean out and top off with OIl. Regrease the Ring gears etc. Out the box these are usually dry/very low on oil. Have the diff oil on hand before you start. Best to completely renew all while you are in there. Start wrenching. You may simply need a new Ring gear. Best case. Just also check the front diff well also, As it usually follows the rear, wear wise. But usually the Rear wears out first. A sign that you need to do maintenance overall. Every 10- 15 runs needs some preventitive maintenance. Your mileage will vary. Better to maintain it periodically before the parts break. Costs less in the long term.
When it was new out the box, ideally you would have checked everything first.
These are not truly RTR. Yet most do run them out the box like that anyway. I always rebuild my RTR rigs when new before running them. I also learned the hard way after my very first Arrma.The diffs oil is usually very low and grease is usually slim to none 99% of the time.
These are good RC's, just that you need to go over them well before running them.

 

[SrC]

Best to always replace Both the Ring and Pinion gears with new ones, together as a set. One new and one used together will wear out both much faster. Especially with the Plastic one being reused. Shimming may also be necessary. Check the backlash closely. Too much backlash/ wider mesh also causes accelerated wear.
Simply user error.

 

[Tex Koder]

Best to always replace Both the Ring and Pinion gears with new ones, together as a set. One new and one used together will wear out both much faster. Especially with the Plastic one being reused. Shimming may also be necessary. Check the backlash closely. Too much backlash/ wider mesh asl causes accelerated wear.
Simply user error.

Agreed.
On replacing Both with New.

 

[Heinz]

+1
Yeah usually the rear diff goes out first. Also need to Open up the diff completely , both front and rear diffs. Clean out and top off with OIl. Regrease the Ring gears etc. Out the box these are usually dry/very low on oil. Have the diff oil on hand before you start. Best to completely renew all while you are in there. Start wrenching. You may simply need a new Ring gear. Best case. Just also check the front diff well also, As it usually follows the rear, wear wise. But usually the Rear wears out first. A sign that you need to do maintenance overall. Every 10- 15 runs needs some preventitive maintenance. Your mileage will vary. Better to maintain it periodically before the parts break. Costs less in the long term.
When it was new out the box, ideally you would have checked everything first.
These are not truly RTR. Yet most do run them out the box like that anyway. I always rebuild my RTR rigs when new before running them. I also learned the hard way after my very first Arrma.The diffs oil is usually very low and grease is usually slim to none 99% of the time.
These are good RC's, just that you need to go over them well before running them.

I guess there is a lot to be learned on my part in terms of preventative maintenance. It's frustrating though that they're not really RTR out the box as you mention.

Your advice along with others who have taken the time to reply will be taken onboard.

 

[Sheed85]

Best to always replace Both the Ring and Pinion gears with new ones, together as a set. One new and one used together will wear out both much faster. Especially with the Plastic one being reused. Shimming may also be necessary. Check the backlash closely. Too much backlash/ wider mesh asl causes accelerated wear.
Simply user error.

Yea, after I looked at the prices, it was like $3 more to get both so definitely worth it to replace both

 

[CosmoM3]

the teeth on your diff(s) are slipping - I know that sound very well...

Another reason why I dropped the 3S BLX models as a whole and pay the extra money for the 6S line as everything is just reinforced with better materials, which you'll end up replacing anyways on the 3S models.

 

[SrC]

That's what she said...

 

[Heinz]

Well, I found the cause of the grinding. It's a worn input gear.

 

[Sheed85]

Way worse than mine looked! But glad to see you found the cause. Cheap and easy fix, but would suggest as others said to replace both gears. It's only a few $ more