Results 1 to 36 of 36
  1. #1
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31

    Two stripped spur gears in 10 minutes.

    Any ideas why this might be?

    Both times I set the gear mesh as per the manual (using a piece of paper) and the slipper clutch a 1/2 turn from full tightness. Yet both times within about 5 minutes using a 7-cell NiMH the spur has stripped.

    When it happens the vehicle makes a crunching noise when moving, and I noticed too that when I try to adjust the slipper clutch, even when I tighten it all the way you can hear the high pitched squeal from it slipping.

    The stock spur lasted for about an hour of run time. I'm not sure if the first strip was caused by debris getting into the gear box or not though. But these last two times I'm almost 100% positive it wasn't.

  2. #2
    RC Racer
    Join Date
    Jul 2011
    Location
    Sioux City, Iowa
    Posts
    186
    Was there a lot of heat from the slipper? I had problems with heat on my nitro revo. Replaced slipper clutch shoes and so far so good

  3. #3
    RC Qualifier
    Join Date
    Jan 2013
    Location
    Biggest Little City In The World
    Posts
    737
    make sure there is no side to side or up and down movement on the slipper clutch. Some times when bearings wear out the shaft will get sloppy and cause spurs to strip. Check the idler gear got this same problem. The idler gear has 2 bearings in the gear. Make sure the shaft the idler gear rides on. Iis it still straight and not bent or broke? Also did you land real hard lately? You may have bent the chassis or tweaked something else. When nothing looks obvious you gotta ask the "what if" questions and look out side the box even if it does seem a little far fetched. Maybe the motor is slipping in the pivot mount. I use a star washer on my motor mount screws. They help the mount screws from coming lose from vibration and torque.
    "You just got passed by a Traxxas"

  4. #4
    RC Racer
    Join Date
    Sep 2012
    Location
    Western Australia
    Posts
    217
    Id have the slipper clutch at least 3, to 3 and half turns from fully on, a half turn out wouldn't allow much slip at all. Id say that's the problem.
    PHOENIX Bandit,Summit,Funny Car,Darkrayne Rustler

  5. #5
    RC Qualifier
    Join Date
    Jan 2011
    Location
    Atlanta, Ga.
    Posts
    384
    Quote Originally Posted by Stach35 View Post
    Id have the slipper clutch at least 3, to 3 and half turns from fully on, a half turn out wouldn't allow much slip at all. Id say that's the problem.
    3 to 3 and a half turns will just sit and squeal. I run mine all the way tight and back it off a 1/4 of a turn. Never gave me any issues. I have also only stripped a spur gear when my pinion came loose one time. My guess would be bearings in the tranny or the mesh isnt correct. I use to use the paper method, but I soon learned it is easier to eye ball it. The paper method always seemed to leave too much play for my liking.
    Nitro Rustler, Rustler HW Brushless Motor, ESC

  6. #6
    RC Turnbuckle Jr. rag6's Avatar
    Join Date
    Mar 2008
    Location
    Accepting requests for bashing at GREENWOOD BASHPLEX in Pittsburgh PA!! Check the thread in the track buddy forum and reply there or pm
    Posts
    15,237
    Check to make sure the slipper pads did not break or crumble. If 1 goes, that whole assembly will sit crooked. destroy the spur, and slip like crazy.
    Ya can't polish fertilizer...

  7. #7
    RC Racer
    Join Date
    Sep 2012
    Location
    Western Australia
    Posts
    217
    Well.. from everything I've read/seen on the net regarding the Bandit/Rustler clutches - a fair few have recommended the 3-3.5 turns off fully in. I'd still try that and see if it stops it stripping the spur!

    I'm running about 3 turns from fully in on my Bandit with a fairly powerful 9T 4000kv 4 pole SC motor and it's perfect for me. No squealing here... if i had it 1/4 turn from all the way in id destroy the teeth on my spur easily.

    All im saying is.. it couldnt hurt to try.
    Last edited by Stach35; 04-11-2013 at 06:37 AM.
    PHOENIX Bandit,Summit,Funny Car,Darkrayne Rustler

  8. #8
    RC Turnbuckle Jr. kdvanb's Avatar
    Join Date
    Aug 2011
    Location
    Grassie Ontario Canada
    Posts
    3,138
    Make sure the motor screws are tight
    Slash 2wd, Slash 4x4, 30th digger, Rustler VXL

  9. #9
    RC Racer
    Join Date
    Feb 2013
    Location
    Portland, OR
    Posts
    155
    Quote Originally Posted by Stach35 View Post
    a fair few have recommended the 3-3.5 turns off fully in.
    Thats weird cause my truck for sure would not even move that loose. I run at about a 1/4 turn out.

    You need to tear your tranny apart if your clutch is not the problem. Good luck.

  10. #10
    RC Champion
    Join Date
    Mar 2011
    Location
    Zeeland Michigan
    Posts
    1,230
    Quote Originally Posted by Stach35 View Post
    Well.. from everything I've read/seen on the net regarding the Bandit/Rustler clutches - a fair few have recommended the 3-3.5 turns off fully in. I'd still try that and see if it stops it stripping the spur!

    I'm running about 3 turns from fully in on my Bandit with a fairly powerful 9T 4000kv 4 pole SC motor and it's perfect for me. No squealing here... if i had it 1/4 turn from all the way in id destroy the teeth on my spur easily.

    All im saying is.. it couldnt hurt to try.
    Even Traxxas support says tighten up then back off 1/4 to 1/2 turn . Every clutch has a sweet spot .
    1 Rusty VXL

  11. #11
    RC Champion
    Join Date
    Mar 2011
    Location
    Zeeland Michigan
    Posts
    1,230
    On page 23 of owners manual shows how to set up your clutch . Hears the manual for the Rustler .http://traxxas.com/sites/default/fil...0-120912_4.pdf . Look at page 23 .
    Last edited by rhardy60; 04-11-2013 at 08:41 AM.
    1 Rusty VXL

  12. #12
    RC Turnbuckle Jr. Dadx2mj's Avatar
    Join Date
    Aug 2007
    Location
    So Cal
    Posts
    21,511
    My guess is you are using the L shaped wrench that came with the truck to tighten down the motor screws. Those tools will get you going but I strongly suggest getting some better tools. I am thinking the motor is slipping on you changing the mesh and stripping the spur gear.
    BlindMan Racing
    Rusty - MERV - Pede 4x4-Alias
    SPC Lipo Power

  13. #13
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Yes, I am using the included L shaped wrench. However when I've gone to loosen the motor, the screws have remained very tight. So I would imagine that means the motor didn't move?

    I'll try the 3 turns (or at least more than 1/2 turn) and see if that changes things, thanks.

    Haven't checked the slipper pads this second time around, but the first and second time the spur stripped I did and they looked fine. I'll check that. Unfortunately I didn't notice if there was a lot of heat from the slipper either.

    Most of the riding has been on the street. I think I've only sent it airborne (purposely) maybe 5 times. What's interesting is the first two strips occurred while riding on the street. This last time, though, I think it happened right after / very soon after it rolled down a hill and landed (it didn't look very hard) on the pavement. Evidently the black motor protector thingy took some of the impact, because where it snaps in to the underside of the body, one of the sides was out of place so I had to snap it back in. But again it didn't seem like that hard of an impact. Maybe it was though?

  14. #14
    RC Turnbuckle Jr. Dadx2mj's Avatar
    Join Date
    Aug 2007
    Location
    So Cal
    Posts
    21,511
    Well there is only two things that can cause the spur gear to strip...

    1- The mesh is not set correctly, the mesh is moving, or there is a bent motor shaft or input shaft causing the mesh to tighten / loosen up

    2- There is some sort of debris getting in between the pinion and spur gear.
    BlindMan Racing
    Rusty - MERV - Pede 4x4-Alias
    SPC Lipo Power

  15. #15
    RC Turnbuckle Jr. rag6's Avatar
    Join Date
    Mar 2008
    Location
    Accepting requests for bashing at GREENWOOD BASHPLEX in Pittsburgh PA!! Check the thread in the track buddy forum and reply there or pm
    Posts
    15,237
    The 3 bolts holding the spur on must be tightened evenly, and not over tightened.

    If you ever locked the spur down and overtightened it, the clutch plate, flexible bowl shaped spur, or slipper ring could have been distorted.

    I have even gotten brand new stock spurs that were warped. Not traxxas fault as I am sure that happened in shipping, or when a lhs employee dropped a case of nitro fuel on it or something. But the spur is flexible.Especially the 90t. You can hold it between your index and thumb and bend it without too much pressure.

    If your locking it down very tight (could have overtightened and damaged something), and its still squealing(maybe some grease on the slipper pads?), you may want to pull the whole assembly off and clean it, inspect it, and reassemble, replacing anything that may have been damaged, distorted or warped.

    I cant agree with dad that there are only 2 things that cause a spur to strip, but the 2 he mentions are the most common.
    Ya can't polish fertilizer...

  16. #16
    RC Turnbuckle Jr. Dadx2mj's Avatar
    Join Date
    Aug 2007
    Location
    So Cal
    Posts
    21,511
    I cant agree with dad that there are only 2 things that cause a spur to strip, but the 2 he mentions are the most common.
    What you outlined is another possible scenario for the same thing, bad mesh. Bad mesh for whatever reason or debris are the two things that will kill a spur gear as described. You can also just wear out a spur gear but not int he time frame mentioned.
    BlindMan Racing
    Rusty - MERV - Pede 4x4-Alias
    SPC Lipo Power

  17. #17
    RC Competitor
    Join Date
    Mar 2013
    Posts
    86
    I had issues with the motor screws getting loose after each runs and damaging the spur teeth. So what I did was put tiny bit of tread lock and tie it tight. After 20 mins of run time I would check the screws to make it tight, but don't over tighten it. Overtime these screws do come loose, but the tread lock will greatly slow it down so you will have time to check again. Now my stripping gears is eliminated.

  18. #18
    RC Champion
    Join Date
    Mar 2010
    Location
    Hackettstown,NJ
    Posts
    1,470
    I'm going with a mesh problem either from incorrect setup, motor screws being loose or something bent or warped with the shaft or the gear. My Rustler and both of my Slashes run 4 pole motors and I can't remember the last time I stripped a spur gear.I only run the slipper 1/8 turn out from full lock and never had a problem. I've snapped the main shaft several times but never stripped the gear. Setting mesh isn't an exact science and I don't trust the paper method. What I do is tighten the gears together then back off the pinion just a hair. what I look for is just a bit of play in the mesh. If you look closely you can see the teeth rock back and forth just slightly. Now you want to rotate the spur gear and check for binding and or too loose a mesh. These gears are cheaply made and not always perfectly round. try and find a happy middle ground and if you can't, try another gear.. I only change spur gears when changing ratio's for racing or bashing to control heat.

    To the original poster.. I'm sure you checked everything you can think of but obviously something is wrong. Have you checked the input shaft for wobbles from a bad bearing or possibly bent? also checking the motor mount screws is iffy at best. The stock mount is plastic!!! It can warp and twist easily. Try moving he pinion when the motor is tightened down. If you can move it at all you found your problem.. These motors have alot of torque and can easily shift around causing problems.
    Last edited by cenracer1; 04-11-2013 at 04:12 PM.
    Maxx3.3/ rusty5700/ slash3800/ slash5700 /4tec3.3

  19. #19
    RC Racer
    Join Date
    Sep 2012
    Location
    Western Australia
    Posts
    217
    Just wanted to apologize for my last post saying 3-3.5 turns out... was thinking about the pro-line trans in my Bandit lol... Good one!! :|.

    Looking at the Traxxas recommendations i'd try about a 3/4 turn from fully on.

    Id also check the motors shaft for any bends.

    Apologies once again and good luck with it.
    PHOENIX Bandit,Summit,Funny Car,Darkrayne Rustler

  20. #20
    RC Champion
    Join Date
    Jan 2008
    Posts
    2,867
    Mesh is the biggest thing. You can have the slipper loose or tight, neither will cause the spur gear to strip. I've gone through a rash of them at one time and my biggest problem was the motor moving on the trans even with the screws tight. Stock screws don't have a wide enough base to spread out the load on the case. I moved to Traxxas 3.3 nitro motor mount screws that have a larger head to upgrade. On the plastic case they still slipped. I switched to lunsford fat boy motor mount screws and it worked better. My aluminum trans really took care of the motor moving after I got it tight though.

    Traxxas spur gears can be warped and slightly out of round right out of the package. It seems to be more prevalent on the larger gears vs smaller ones. I've noticed the spurs being out of round the most problematic to setting mesh. If you use the paper method you might only be set right on one section and 60 to 90 degrees from that point it might be significantly looser. Loose enough you could wipe it out. I end up setting the mesh at one spot, snug the motor (not locked down) and roll the spur by hand while watching the mesh. If I see a section that is looser than where I set it first I'll loosen up the motor and close the gap and roll the spur by hand again. I end up checking the mesh in 3 areas at least and split the difference so I'm not overly tight and not excessively loose. I don't have a problem between the aluminum trans and paying close attention to overall mesh and not just one spot.
    Brushless 9cell/3s Street Rusty

  21. #21
    Marshal ksb51rl's Avatar
    Join Date
    Nov 2006
    Location
    Northern NJ
    Posts
    20,527
    I'm with cenracer1: 1/8 to 1/4 turns is what I run, but mostly 1/8.
    Alt-248 on the number pad =

  22. #22
    RC Turnbuckle Jr. harry697's Avatar
    Join Date
    Jan 2008
    Location
    South Jersey
    Posts
    8,407
    Not sure if it's been mentioned already, but I'm gonna guess that you're running in loose dirt with the stock gear cover? I did that one time with a brand new truck and destroyed the pinion and spur within 10 minutes. The hole in the stock gear cover allows a lot of dirt in and traps it there. Never had an issue with it on the race track because it was well-groomed clay and there wasn't much dirt or debris to pick up. After running in loose gravel and ruining the gears, I replaced the pinion and spur and left the gear cover off. No more problems after that aside from an occasional clicking noise from a small piece of dirt getting embedded in the spur gear.

    Another option is the RPM gear cover. It doesn't have that gaping hole by the diff output and seals much better than the stock cover.

    One more thing to check. Loosen the mesh and check for end play in your motor shaft and trans output shaft. If the first failure was from dirt between the gears, you may have wiped out a bearing. A worn bearing will make setting the gear mesh impossible.
    Last edited by harry697; 04-11-2013 at 10:42 PM.

  23. #23
    RC Turnbuckle Jr. rag6's Avatar
    Join Date
    Mar 2008
    Location
    Accepting requests for bashing at GREENWOOD BASHPLEX in Pittsburgh PA!! Check the thread in the track buddy forum and reply there or pm
    Posts
    15,237
    You can also just wear out a spur gear but not int he time frame mentioned.
    Unless there is drag in the drive line(seized bearing, overshimmed internal gearbox gears, leaking 300k oil from a diff). I myself broke 2 steel diff ring gears in 2 min of run time due to a leaking "sealed" diff.

    Have you submerged the driveline in water without cleaning and re oiling the driveline bearings? If so check for seized bearings. Your squealing sound with a locked slipper does not make sense, unless the clutch pads are crumbling or there is grease on the pads.
    Have you opened the gearbox and closely inspected the gears for a chipped tooth? If you ever broke a cross pin, steel idler or diff ring gear and missed a chunk, it could fall into the gear mesh, jam the gears suddenly, and all that shock goes directly to the spur. The crunching sound you mentioned makes me think of this.
    Did you buy both gears at the same time from the same place? Could both the spurs possibly be a plastic compound defect from the same batch?
    If you have not dismantled the gearbox and checked things internally, you may want to do so. We are running out of things that could go wrong on the outside of the gearbox...
    Last edited by rag6; 04-12-2013 at 06:14 AM.
    Ya can't polish fertilizer...

  24. #24
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Thanks everyone. Sorry for taking so long to respond. I just took off the gear cover and spur gear and tried to move the motor shaft (I guess that's what you call the thing that the pinion is secured to) up/down/left/right. There is a very, very, very slight bit of play. And I mean very slight. I can't really see the movement but can hear and feel it.

    I can also grab the pinion and pull outward and the shaft moves a bit too (more so than up/down/left/right).

    I don't know if this was how it was when I first got the truck before I ran it, since I never tried it.

    Could this be my problem or is that very very slight bit of play normal?

  25. #25
    RC Turnbuckle Jr. Dadx2mj's Avatar
    Join Date
    Aug 2007
    Location
    So Cal
    Posts
    21,511
    The small amount of shaft play you describe is perfectly normal.

    Do yourself a favor get some good tools and cover the basics. Check to make sure nothing is bent set the mesh properly and get the motor cinched down (need good tools) and you should be fine.
    BlindMan Racing
    Rusty - MERV - Pede 4x4-Alias
    SPC Lipo Power

  26. #26
    RC Competitor
    Join Date
    Mar 2011
    Location
    Twin Cities, Minnesota
    Posts
    63
    +1 on the motor mounting screws loosening, thus widening your mesh and stripping the tips of the spur teeth.

  27. #27
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Instead of getting different tools, I was thinking about putting some blue Loctite or Permatex or Zap on the motor mounting screws. Any reason why this is a bad idea?

  28. #28
    RC Turnbuckle Jr. Dadx2mj's Avatar
    Join Date
    Aug 2007
    Location
    So Cal
    Posts
    21,511
    If you have good tools you wont need the thread lock for the motor screws. If you use the thread lock and it works but you stick with the tools that come with the truck when you go to undo the screws you may have a different problem,,,stripped screws are never fun to deal with. If you are going to stick with the hobby you are going to need some good tools sooner or later or you will be having consent frustrating problems.

    You might also consider some upgraded motor screws. I use Lunsford FatBoys they come with a cone shaped washer that really works well and wont let the motor move from my experience. They are kind of expensive but well worth it IMO.
    Last edited by Dadx2mj; 04-15-2013 at 11:05 AM.
    BlindMan Racing
    Rusty - MERV - Pede 4x4-Alias
    SPC Lipo Power

  29. #29
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Thanks. Recommend any tools in particular?

    And I imagine that the motor mount screws should be tightened as tight as possible then? Because for the times I tightened them before, I did tighten them as tight as they would go. Although I turned the wrench with the short side rather than the long side so there'd obviously be less leverage...

  30. #30
    RC Turnbuckle Jr. rag6's Avatar
    Join Date
    Mar 2008
    Location
    Accepting requests for bashing at GREENWOOD BASHPLEX in Pittsburgh PA!! Check the thread in the track buddy forum and reply there or pm
    Posts
    15,237
    These are the best tools I have ever used:
    http://www.ebay.com/itm/DYNAMITE-Mac...item51a96e6812
    Ya can't polish fertilizer...

  31. #31
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Hey dad, I think I will get those screws. Do you use the long (3x10mm) or short (3x7mm) version?

  32. #32
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Quote Originally Posted by rag6 View Post
    These are the best tools I have ever used:
    http://www.ebay.com/itm/DYNAMITE-Mac...item51a96e6812
    Thanks for the suggestion. I ended up going with the 3 piece 3094 set from Dynamite ($10 cheaper and I didn't need the extra piece.)

  33. #33
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    Update: the Fat Boys and better hex wrenches are on their way. As are some 32P pinions and spurs. Thanks for all the help guys.

    After replacing the spur again, I took a close look at my 25T stock pinion and noticed that the very edge of one of the teeth had a slight chip in it. So I replaced it with a new 23T one, and, while the batteries weren't fresh, the spur hasn't stripped yet. So that very well could've been the problem. I didn't closely look at the pinion before, unfortunately. Just didn't expect it to have chipped since it's metal, but I guess I was wrong.

    I do have one other question for now though. When traveling at slow-er speeds and coasting, my truck is making a non-linear, chug-a-chug sound. Sounds like it's coming from the tranny. I know this sounds silly to ask, but is this normal? I've driven the truck so little and it's been days since I last drove it, I forget whether or not it always sounded like this...

  34. #34
    RC Turnbuckle Jr. rag6's Avatar
    Join Date
    Mar 2008
    Location
    Accepting requests for bashing at GREENWOOD BASHPLEX in Pittsburgh PA!! Check the thread in the track buddy forum and reply there or pm
    Posts
    15,237
    Quote Originally Posted by FTFTWW View Post
    Thanks for the suggestion. I ended up going with the 3 piece 3094 set from Dynamite ($10 cheaper and I didn't need the extra piece.)
    I went to dynamites site, and there is no 3094 part#... do you have a link?
    Ya can't polish fertilizer...

  35. #35
    RC Turnbuckle Jr. rag6's Avatar
    Join Date
    Mar 2008
    Location
    Accepting requests for bashing at GREENWOOD BASHPLEX in Pittsburgh PA!! Check the thread in the track buddy forum and reply there or pm
    Posts
    15,237
    The steel spurs are not light weight. My hot racing 32p steel spur weighs 5x a jato 32p or stock rusty 48p spur. Do you have any non metal 48p spurs???
    Ya can't polish fertilizer...

  36. #36
    RC Enthusiast
    Join Date
    Jun 2011
    Posts
    31
    I've been using plastic 48p spurs and the 32P spur I bought was also plastic (the Jato).

    Sorry, wrong part #, I actually got the 2904.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •