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Eating spur gears too fast......

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chrisexv6

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OK, I'm getting tired of losing spur gears every 8 tanks or so. I lost another last night, and as usual I checked the usual suspects. Gear mesh was set with the plastic method as well as the "feel and hear" method. I tightened the gear all the way then backed off about 1/4 turn.

Motor mount is intact. Clutch bell looks fine. BUT!!! the tranny screws were a little loose (and actually one might be stripped, and another fell out totally............what a horrible design). So my question is, would that cause me to lose spur gears like crazy? A friend of mine got a Tmaxx about 3 weeks after I did, and he doesn't lose gears at all.............why would my tranny loosen up but not his?

I'm thinking the brass insert kit that I've seen on the net is a good investment to help fix this?

Thanks in advance!!!
-Chris
 
A loose tranny can do it. Anything that causes the gear mesh to shift can be the culprit. It's good that you checked the motor mount. I'm not sure what you meant by setting the mesh with plastic method. I'm not familiar with that one. I usually use the paper method. That works great. As far as tightening your tranny mounts. Find the stripped screws and take them out. Then put a few drops of medium CA glue in the holes and gently thread the screws back in until they are just a little snug. Let the CA dry and then tighten the screws down just a little bit more. The CA will form reasonable threads in the plastic again and should give you enough tension to hold the tranny in place.
 
I purchaed that brass insert kit for my tranny mounts and have been very happy with it. The kit includes 6 inserts, 6 screws and a drill bit to enlarge the hole in the case to accept the inserts. Just becareful when you are drilling the holes that you don't go too far or have the drill at an angle. The best part is that it only costs a few bucks to do it.
 
A few things to look at.
You said you looked at the motor mount. I recommend that you remove it, wash it and inspect it again. Sometimes there can be a crack in one of the ears that goes un seen until its removed. I had this issue once as well as HB.

Look to see that your engine / bell is not being tightened down crooked. Just the smallest angle can cause wear on the teeth and prematurely trash a spur.

Look for broken bottom chassis braces. Anything that causes chassis flex can trash the spur as well.

Can you describe or post a pic of the bad spur?
 
On my car the part that holds the gears that swings out and locks the second gear afet the rpms gfet to the right point (not sure of the name of the part), was defective someohow and it caued me to loose alot of spur gears, This was not on a TMAXX but you might want to check that opart out
 
Here is a pic:

http://www.chris-and-kathy.com:8081/images/tmaxx/spur2.jpg

Basically a bunch of teeth are chipped off, and the rest seem to be *slightly* rounded off. I also have small plastic shreds on the tranny, chassis, exhaust, etc, so I figured the teeth were rounding off somewhere.

I thought that busted teeth meant it was too tight, but I thought I had it set correctly (although the nut never seems to tighten down to a dead stop, I tighten as much as I can and then back off 1/4 turn).

Thanks in advance!!!
-Chris
 
Typically busted teeth are the result of a mesh that is too tight, but this looks like a case where the mesh is either too loose or is pulling away during operation.

The mesh separating during operation can be caused by a number of things, and you already narrowed the field for us. You loose tranny is probably bouncing around. This will cause the mesh to go from one extreme (too tight) to the other (to loose). The end result is a few broken teeth and several rounded or ground down teeth (as your picture illustrates). I would fix the tranny issue first.

Next check the stuff Eddy mentioned; they are all potential causes for Spur gear abuse and destruction.
 
Hey guys I'm reviving this thread because my maxx is doing the same thing... my mesh is set properly and there is no play in the trans... and I've gone through 3 spur gears in 3 days... (I'm a newbie to this too sorry). My Maxx I bought used and converted it to a 2.5 from the original .15 pro engine. Is there a different spur gear I have to buy or are they the same? I'm currently using the 72 tooth (that's what it came with) Any info appreciated thanks.
 
i found that it was my tranny, just like candyman said anythign that moves can mess it all up. that is what happened to me. i went and got a new tranny case from Imbroken. the whole design is messed up on it. all 8 of my screws fell out!

bryan
 
my tranny's mounted pretty solid, I've checked that quite a few times... is there a possibility that the slipper pegs being worn out could cause this problem? I just finished tearing my maxx apart and the slipper clutch discs are MELTED to the spur gear.... :wtf:
 
melted??? i havent ever had that happen before. could it be that the slipper is too loose?

bryan
 
Yeah bud melted......8-0 That's why I'm wondering if those pegs have been causing my problem all along, because like I said they were set to the proper speck.... I'm getting ready to throw this thing through the window... lol. :batman:
 
Those clutch pegs could have been toasted when you got the truck. Once the pegs are fried your friction surface becomes the spur gear. No good.

Get an RRP replacement.
 
What's an RRP replacement? Like a good metal one and new pegs? Oh one more question.... there were 6 pegs there, but provisions for 12.... should I have 12 in there or just the 6?
 
The RRP slipper kit is awesome, & worth the extra $$.. I had my disks melt right through my spur at the East Coast bash....

slipper.jpg
 
I took this from a post I made a year or so ago.
There are many ways to adjust the slipper but this way always works.

I feel I need to do a little :preachin:

Metal or plastic doesn't matter as far as striping the transmission.
The key to trany health is the slipper adjustment. The slippers main purpose it to buffer the transmission from torque and shock. Adjusting it properly is important weather its stock or aftermarket. If you use a stock slipper setup make sure you have ALL the holes filled with friction pegs and make sure you replace them when they get worn.

Adjustment is easy. Start by GENTLY snugging the adjustment nut down then backing it off 1/8th of a turn. This will get you in the ball park. Start and warm it up. Hold your Maxx down tight to the ground with the front wheels against a wall. gently give it throttle. If the spur slips tighten it just a tad. Give it a short blast of 3/4 to full throttle. The slipper should slip from 1/8th to 1/4 turn no more no less. Tighten or loosen the adjustment as needed. If you have a hard time telling if it has slipped use paint and mark a spot. This will help see if its slipping.
I check my spur every time I start my Maxx. Its a good habit and everyone should do it.

I hope this helps.

-Ed
 
Fasteddy thanks for the pointers, and Imbroken, my spur gear did exactly what's in your pic when the last one blew out. The previous 3 just got the teeth chewed... but #4 got melted...

There are only 6 pegs in the gear, that's what the maxx came with when I got it... It didn't know if it was supposed to house 12 at once or not, but it makes sense to me.

Anyway, how much is the RRP slipper kit? I want to get that and a metal spur gear.
 

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