RC4WD Gear Reduction

[Lil Giants]

I bought this trk from FGD, I don't know whether it's the 3:1 or 4:1 RC4WD reduction unit. Last night it started to make a lil noise & two hill climbs later the reduction seized up! There was plenty of charge yet, so the brushless motor had ample power, but couldn't spin the GR at all, even after disconnecting from the trans.

Anybody else have this happen?

I got the reduction apart, emery clothed the shaft, but I didn't have anything to hone the bushing in the housing. Lube up with lithium grease & put it back together. The trk up on blocks, the bl motor has spinning for last 20 mins & it sounds ok... I even gripped the wheels by hand for a few minutes to make the motor/gr work pretty hard... it still sounds ok. :confused:

I haven't used this trk much at all in the couple yrs I've had it, it might be on its 10th charge.

http://img.photobucket.com/albums/v150/protrker/Jan%2013/002_zpsbb9b3ad2.jpg (http://smg.photobucket.com/user/protrker/media/Jan%2013/002_zpsbb9b3ad2.jpg.html)

[Szczerba]

what pinion goes in the unit? I believe that is the only way to tell which unit is what. I have the 4:1 and the 2:1.

I believe the 2:1 uses the 21 tooth pinion.
http://store.rc4wd.com/Pinion-Gear-for-21-Gear-Reduction-Unit_p_1919.html

And the 4:1 and 3:1 use a 12 tooth pinion
http://store.rc4wd.com/Pinion-Gear-for-31-and-41-Gear-Reduction-Unit_p_1920.html

Not sure how to tell the 4 and 3 apart. So if you have the 21 or 12 pinion, you'll at least narrow it down a bit. Heck they make a 1:2 as well! That takes a 15t pinion.

Also, these units were not made to take a low turn motor. The internal gears wont hold up for long.

[Lil Giants]

I didn't count the # of teeth, but it's definitely the smaller pinion. The brushless motor attach to the GR is one that RC4WD sold at the time with their GR. The motor/GR is connected to a R2 RC4WD trans, even in 2nd gear the trk is not quick at full throttle. I would compare it to my 12v GL's in 2nd gear (3:1 infront of trans & 2.1:1 after trans) as being just a hair faster, so the kv must be quite low. And the input voltage is only 7.2v.

[ihbuilder]

Joe is the bushing oillite ? and was there grease in it ?

[Lil Giants]

Yes it is oillite bushing.

Sorta had grease... I was debating whether to relube with the white lithium or spray on graphite, thought maybe the graphite might interfere with the oil release of the bushing. :thinking:

[ihbuilder]

put some white lithium grease in

[9W Monighan]

Definitely sounds like a dry bushing. I don't like oilite bushings because they gum up.Especially in the dusty environment you work in. A good solid bronze bushing may work better. Better yet, can you install a ball bearing? Run the whole gear train in oil? I don't know anything about the drive you are using just going on what happens with dry bushings.
Another thing, Can the motor pinion be supported on the end? Probably not because the mounting holes are slotted to accommodate different pinions.
With the way you overload your trucks all the time, there could be some flexing on the pinion shaft making it run out of alignment with the driven gear.
Same goes for your rears that you said you have problems with.

[Lil Giants]

Another thing, Can the motor pinion be supported on the end?

Yes it does, the motor pinion has enough stub sticking out that fits into a pilot hole of the GR output shaft, eliminating any motor shaft flex.

[Espeefan]

Wasn't there a post on the forum where a member had replaced the bushing with a ball bearing on his RC4WD planetary reduction? I have one of these planetary reducers, but never ran it. The bushing on mine seemed a bit sloppy in supporting the output shaft. Maybe that would improve the gear mesh.