New build - Loose gear questions

[Jus]

if the pin groove was too deep there would be no play? You're making no sense, unless we're talking about two different things.

I just did one of these the other day so I know it works. I mirrored a tranny and when I put it back together I did this just for the heck of it.

[Slaughter]

The top gear is sandwiched between two bearings. If the groove was only as deep as the diameter of the pin then the shaft wouldn't move. But because the groove is 2-3x deeper, it allows the shaft/pin to move between the bottom of the groove and the bearing. Same thing applies to the pinion in the axle. Try it, you will see.

Originally Posted by Jus

if the pin groove was too deep there would be no play? You're making no sense, unless we're talking about two different things.

I just did one of these the other day so I know it works. I mirrored a tranny and when I put it back together I did this just for the heck of it.

[Natedog]

Originally Posted by Slaughter

Thanks for the suggestion. I have never owned a car where the spur can move back and forth across the pinion, but maybe these are different because they are meant to go slow. 1/16 is actually a lot considering the spur and pinion are the same width. It causes noise and uneven wear. Unfortunately it can't be shimmed because the deep groove in the gear is allowing the shaft and pin to slide.

I just checked out the heavy duty gear set for the axles and that looks like it would fix the output shaft from sliding in and out. Axial has in the description that it reduces the slop in stock gear set. They are pricey, but at least it is a solution.

Can someone else check their spur to see if it moves back and forth?

Thanks

Mines same way...too much slop due to poor design and manufacturing. Buy some Kyosho or Yokomo steel shims and shim it up til it's almost gone. Things will last longer and run smoother.

Originally Posted by Spiike

When i built my axles and transmission, I had the same problem, and axial did not give enough grease to make your gears "water resistant" so my suggestion to anyone who builds a kit, you need to go and get a large tube of multi purpose grease, stuff that is water resistant, and just shovel that grease in there, and after you put it together there is not near as much play, it takes about 10 minutes of working the grease into the gears, and the grease will pour out the outputs and the spur gear area, this is normal and should solve your problem. I have pictures in my build thread of the axle re-build as I thought I gotten rocks or sand inside the axles.

I also wrote this suggestion in another thread of "what you need to build kit" with a few other suggestions you could quickly scan over and get ideas on what you need.

First Time Building A Kit!!!

hope that helps

Grease is a lubricant, not shim material.

Originally Posted by meatmonkey

I too noticed some play in my trans input shaft and pinion gears when I assembled my SCX a few weeks ago. I don't remember having these issues when I assembled my AX-10 some years ago.

For the axles I just put a 5mm Teflon washer (I believe it was a Traxxas item) under the pinion before inserting it into the diff case/inner pinion bearing. It holds the gears slightly tighter together, but they don't seem to bind or such. Then I put another washer on the pinion before putting the driveshaft on, slid the driveshaft up against the washer and tightened both setscrews. Seems to be working good cause I have almost ten hours of use on it and they are still fairly tight, with just a tick of in and out play.

To remedy the play in the trans input shaft I had to stack several small 5mm steel washers onto the input shaft just under the drive pin for the slipper. It took some finangling to find the right height so that the slipper nut pulls the slipper driver down over the drive pin and bottoms on the washers, but not so much that it sideloads the input shaft bearings. Now it too has just a tick of play.

I tried shimming the bearings in the case, but it just kept the case halves from coming together because the play is indeed between the drive pins and the slipper driver and upper gear.

Sorry no pictures, but it wasn't too hard, just time consuming.

Precisely! I dont recall if my AX-10 had this in n out play, but it did have excessive radial play.

[Slaughter]

Just got a response back from Axial. They said this is normal and will not affect performance. I don't know about normal since I have never owned another RC with any play in the spur, but oh well.

[Natedog]

Originally Posted by Slaughter

Just got a response back from Axial. They said this is normal and will not affect performance. I don't know about normal since I have never owned another RC with any play in the spur, but oh well.

LOL, normal for them. I've been building RC kits for years and never had one wtih this much slop in the input shaft...LOL>

[Spiike]

its normal = room for grease, = grease it up and its resistant from mud and dirt

[Erin]

You did remember to put part # AX30499 on the spur gear shaft before adding spur assembly, correct?

I only ask because in my haste to throw a tranny together a bit ago i forgot this pc. And i had exactly the same amount of slop your vid shows. Now its mayb a 1/32" of play with correct pc installed.

Just a thought

[Natedog]

Originally Posted by Erin

You did remember to put part # AX30499 on the spur gear shaft before adding spur assembly, correct?

I only ask because in my haste to throw a tranny together a bit ago i forgot this pc. And i had exactly the same amount of slop your vid shows. Now its mayb a 1/32" of play with correct pc installed.

Just a thought

Yes, installed on both my Axial trannies.

[meatmonkey]

Mine was almost as bad as the vid, with the correct parts installed. I ran it for a couple packs and didn't like how loud it was.

Now that it is shimmed the thing is much quieter. It just sounds like a more quality assembly.

I assembled an AX-10 a year ago and it's transmission didn't need any shims on the input shaft, but did require one on the output shaft.

[celt]

There is no technical merit in having that much lateral play in the shaft.

1/16" of an inch play might be "normal" in terms of how the parts are tooled, but it is not good.