Binding gears or no?

[chrisexv6]

I just installed the FOC into my tranny, but after I put everything back together, I'm getting something weird.

Without the screws in the case, or with the screws only half tightened, the spur spins a lot freer than once the case is completely tightened down. Granted, even with the case tight its not like the tranny doesn't spin at all, its just not as nice as without the screws tightened.

I removed all the bearings and cleaned them out with denatured alcohol. I removed all the gear shafts, and ran with just the spur shaft in there, and it spun freely. I added the two speed shaft back in, and it started "binding" again.

Pulled the 2-speed shaft apart, cleaned it, re-assembled, still same issue.

Are the gears on the end of the 2-speed shaft supposed to spin freely? I seem to be feeling/hearing a little drag when I spin them, I dont know if thats correct or not.

Any ideas would be appreciated!!!
-Chris

 

[gettinintoit]

What kind of binding would be helpful. I had the same problem when i installed my two speed in my s-maxx. I just took it apart and put it all back together and that seemed to fix it. I had something tweeked somewhere. That could be your problem but it sounds like you have went through it pretty well. Remember start with the most basic idea and go from there. Its after you get it all apart that you realize it was so simple.

 

[lykan]

Maybe somone who knows for sure will chime in.

I hear that whe you install the foc, you dont get that hurky jerky motion of popping in nd out of gear when you are near idle. I am thinking it removes some of the clutch that is in the tranny itself.

I got the impression that the only slip tahat should be left at all was the cluth bell. Meaning I thought the spur gear no longer turned freely after a FOC

 

[chrisexv6]

Well, the only way I can describe it is if you spin the spur gear, you can tell when its not binding (i.e. as it stops, its still spinning, just very slowly and eventually comes to a stop).

With the way mine is after all the screws are tightened, it spins OK, but as its "slowing down" you can tell that instead of spinning down, its almost like something "hits the brake" and the gear comes to a semi-abrupt stop at the end, not very noticeable, but noticeable enough if you know how it slows down with no gears inside the tranny or the case not tightened completely.

I dont know what it could be, I was guessing the input shaft, but the fact that it works fine without anything in the tranny case leads me to believe its not that.

As far as the 2 speed shaft, when I spin it I can hear a "rubbing" noise, kinda like the noise you get if you rub two piece of paper together. And it definitely doesn't "spin down" like things attached to a ball bearing, but I did notice there is a needle bearing on the 2-speed shaft, so maybe its NOT supposed to "spin down" the way a ball-bearing shaft does.

-Chris

 

[gettinintoit]

mine still makes the same noise. It seems to run good though so maybe there is not that big of a problem. It also doesn't spin that freely. Have you actually drove it since the problem? If you chew up the spur then you know you have a problem. Also what tooth spur gear do you have on it?

 

[olds97_lss]

As for the FOC, it removes the forward/revers clutch. It's not really a clutch as it is a "slammer into gear" device.

You can still spin the spur one way freely, but not the other way. It's always engaged. But there is a one-way bearing in the two speed mechanism that allows this. If it goes bad, the it will spin freely in both directions.

As for binding, I did the same thing. Except, mine was my own fault. I put .5mm teflon washers where I thought they should be, not where the parts exposion says they should be. I had to many in it in to many places, which caused the kind of binding you describe.

 

[chrisexv6]

So, because I can spin the spur shaft both ways, does this imply the one-way bearing is shot?

I checked and re-checked the assembly of the tranny, and it seems correct according to the parts explosion, but it still seems to "bind" when I tighten up the case.

The fact I can spin it both ways freely bothers me more.

-Chris

 

[olds97_lss]

It will spin both ways, but it should turn the center axles when you spin it one way and spin freely without moving other parts when you spin it the other way.

Not sure what the deal is with yours though. You forget a axle pin somewhere?

 

[chrisexv6]

I figured out thats what you meant The spur spins either way, but I only get output in one direction.

Didnt forget any pins, I only had them removed for a very short time, and I made sure everything went back where it came from. I too had the washers in the wrong area, but then realized the 2-speed shaft only had one, the other one I had on it had come from the reverse mechanism that was no longer necessary.

Still having the binding issue after tightening the case though. I dont know what else I can do about it. I put the case on a flat surface, and it doesn't look to be tweaked or anything. I may just be forced to run it and see what happens. Didnt wanna put the motor to more work than it needs to be, but I'm not sure I have any other choice (I really dont wanna just start buying parts to replace for no reason, and find out they wont stop it either).

-Chris

 

[olds97_lss]

Don't know then. All I can say is take it all apart and make sure you didn't add or miss anything anywhere. Personally, I wouldn't run it if there is any binding that wasn't there before. You could toast bearings, gears and like you said, overwork the engine.

The FOC shouldn't cause any extra binding.

 

[chrisexv6]

I tore it apart again last night, I will re-check everything again.

If everything looks correct, any suggestions for next steps? Like I said, I've checked and re-checked everything. Not missing any parts, everything went back where it should (lets face it, its not that complicated of a tranny, especially when you remove the reverse mechanism).

It definitely is something with the 2-speed mechanism. Without that installed, even with the case tight, the spur spins nicely. Put the 2-speed mech. in and tighten the case, it doesn't spin so nice. I've tried swapping the bearing that the 2-speed rides on in the case (with another one from the case), but that didnt help. I dont want to buy new parts unless I'm sure of what it is. Maybe the case bearings are bad? Or how about the needle bearing on the shaft itself?

It seems so simple, yet I can't figure it out

-Chris

 

[chrisexv6]

Just talked to Traxxas, and they said its normal (because I dont feel any resistance when spinning the tranny up, they said its OK).

So figure I dont need to replace any parts, at least thats what they said. How can I tear everything down and clean it? Is denatured alcohol bad for the gears? (I thought it might dry them out, so I didnt wanna use it just yet).

Finally, I noticed that if I spin the clutch end of the 2-speed shaft, it doesn't spin really fast, like a ball-bearing shaft would. I know it uses a needle bearing, so is it normal? While its spinning, it makes a slight rubbing noise (I think I mentioned this in my first post), almost like the noise you get when rubbing two pieces of paper together. Is that OK too?

The only thing Traxxas remotely suggested was checking to make sure the gears were in the correct spot on the shaft itself, but loosening the screw opposite the shift-point adjustment screw, and slightly moving the gears toward the end of the shaft. But when I told them I didnt feel any resistance, they said not to touch that screw.

Hopefully I can get the tranny back together tonight, I'm tired of closing it and tearing it open again. Just figured I wanted to clean everything before I did a final re-assembly.

-Chris