Massive690

I am having issues with the spur gear in my T Maxx. I am running a stock 20 tooth clutchbell with a 72 tooth spur. I stripped out 3 of them in about 1/4 tank of fuel. I am not new to the sport, I checked and rechecked my gear mesh (used a piece of paper), checked all engine mounts and used lock tite. I can not figure out why I keep breaking teeth on the spur.

On the last one I loosened up my slipper clutch about 1 turn. After I ran I checked the spur and I was missing teeth and thel all seemed to be missing at the same intervals all the way around. Which makes me think something must be up with my clutchbell, but I pulled it off and it looked fine, no bent or mangled teeth.

Any suggestions? Only other thing I can think of is that Im running in Minnesota and it is cold and I have chains on my tires. Maybe its too brittle and heavy?

ReaperGN

If your running in cold weather the spur is probably becoming brittle. But it could possibly be the transmission bolts. Check and make sure they are tight. I never had any luck with traxxas spurs with my 3.3 and not at all with my red dot. Robinson Racing makes some beefy plastic ones and steel ones. If you decide to go steel you have to use a high quality clutch bell.

crispyspa

The only thing I can think of is wrong pitch on the clutch bell....but you haven't replaced that, have you? That's stock?

Mclovin350z

Clutch bell bearings, input shaft bearings, missing slipper bushing, orlike Reaper said the trans bolts.

Massive690

yes, clutch bell is stock. Tranny screws are tight.

I might just replace the clutchbell. It looks fine, but its odd that my spur gear is missing 4 teeth, and they are all exactly the same distance from eachother. Its gotta be the clutchbell, but it looks fine.

im out of ideas after that

nitrostam

My Feedback: (1)

bent chassie causing a crooked mesh

1QwkSport2.5r

I've had small bits of sand get stuck in the gear teeth of the spur gear and cause teeth to get chipped or break off completely. I'd look carefully at the clutch bell and make sure the teeth arent wore down too far. If the edge of the teeth on the CB has a blunt/flat edge on the outside, it should be fine. If they look "sharpened" or pointed, I'd put a new CB on it. Steel spur gears (in my experience) have eaten a clutchbell for lunch in 3 tanks of fuel with the proper mesh set. Also - just my 2 cents... When meshing the spur gear, use a piece of notebook paper, not paper you'd use in an inkjet printer. I've found computer paper to be thicker and end up with too much play between the clutch and spur. Notebook paper seemed to get it just perfect so long as the engine was lined up dead straight.

Make sure the engine isnt meshed against the spur crooked. Most engine mounts have enough side play in the slots to get it a little off-center. This could cause it to get spur gear hungry too.

partisan

My Feedback: (1)

Ihave had great luck with the robinson racing products. I always stripped the stock spur gears until i went steel. Instead of eating the spurs so quickly, the clutchbell is what will go first, Ihave had the same spur for about 8 gallons on a .26 big block maxx. The trick to making the clutchbell last longer is to get the robinson hardened ones.

Here is the spur type that I use, mine is 66 teeth, this one is the stock 72.
http://www3.towerhobbies.com/cgi-bin...1p?&I=LXBJB6&P=**

Clutch bell...
http://www3.towerhobbies.com/cgi-bin...1p?&I=LXBJB2&P=**

Just remember to keep the slipper clutch backed off a 1/4 turn. I also just space the mesh by sound, if it sounds tight, then back it off a smidge, when you hold the spur gear, the clutch bell should have very little if no play in the mesh. A nice square mesh is also important.