Transmission Problems

[GholmesA]

I built my CC-01 about 3 weeks ago. Until a few days a go it had been running fine, but now there is a clicking noise coming from the front gear box. This started whenever i attempted to lock the front diff with an extra gear from the rear diff. When i put the front diff back into the chassis it didn't fit quite right, and when I tested it there was a clicking noise coming from the gearbox. So I unlocked the diff, and retested it. The rig was still making a slight noise. It still had power to all the wheels though, and it was driving fine. But the truck still had an annoying clicking sound. It sounds like the gears are hopping around inside of the case. I have taken apart the front and rear gearbox and disassembled everything multiple times. I inspected the teeth on all of the gears and everything looks fine. I have tried mounting the motor again and re setting the pinion on the motor. Then i saw where people were recommending to drill holes through the chassis and bolt down the front gear plate so i did that too. Unbelievably the sound is now worse even after securing the case very tightly. I'm not really sure where to go from here. I have tried everything i know to do based on what I have read. I don't know if i need to replace parts or not. All of the gears appear to be fine and the truck is only a few weeks old. I have cleaned and re greased all of the parts which also did not help. The sound has actually gotten louder since it started. I am also now having problems with the rear diff. I have it locked using the proper parts from the kit, but my wheels are now able to turn separately. It wasn't like this before. When i took it apart it looks like one of the rods is sticking out of the diff just enough to not get locked into the gear, so it just spins freely from the other side. But all of the bearings are lined up with there proper slots. When i take the whole assembly out of the case and insert both rods fully into the diff everything locks tight. But now it wont go back into the case like that. The holes don't line up unless one of the rods shifts slightly, and then it doesn't lock anymore. I'm getting really frustrated I really don't understand why i'm having all of these issues now when the rig was running fine a few days ago aside from some steering issues. Like i said the truck is only about 3 weeks old and hasn't taken any damage or been under heavy use. Any advice would be greatly appreciated.

[Dirt Runner]

Have you rechecked the alignment of the gear on the motor to the gear box? Maybe that if you haven't dine so already. When you locked the front diff did you make sure that the cover in the diff was completely flat and the screws are flush?

The rear diff has some play on the inside it shifts side to side a bit you can try to shim it. Skip to 1:20 to see what I mean. I did this to mine https://youtu.be/jpFteRodEU8

I hope this helps.

[GholmesA]

What size washers did you use to shim the rear diff?

[Dirt Runner]

I went with ball bearings and used the bronze bushings from the kit to shim from the diff side and I had extra bearings that I used which had slightly different widths.

[GholmesA]

On further inspection it looks like one of the gears inside the rear diff got stripped somehow. I'm Thinking about replacing this with the rear diff upgrade. I ordered a new set of gears for the front gearbox and replaced everything but the rig is still making a weird noise. The only thing i can figure is that the front diff is moving inside the chassis causing the noise. Maybe the front diff needs to be shimmed as well? When I tried to lock the front diff the first time with the extra gear it fit in the chassis really tightly. And all my problems started after that. Is it possible that I somehow damaged the chassis when I tried locking the diff the first time? Can you recommend a set of bearings to replace all the plastic ones? I'm still running everything stock.

[Dirt Runner]

For the bearings you can do fast eddies brand they sell the set. You can get it through amazon or vendor here. When you put the extra gear in the front did you make sure the cover and screws were flush? https://youtu.be/2wkH1x5z-2U

[OSRC]

if you jammed one of the 3 diff gears inside the other two, it has to be seated in there perfectly or the sides of the diff bulge out and cause problems. If the diff doesn't drop right in there, the gears are not seated right.

I usually take my dremel and remove the rear lip on the gears where they touch - they seat together much better.

[GholmesA]

It looked to be flush but i guess it wasn't because it didn't fit back right. I replaced the front diff and locked it with the differential locking parts from tamiya and the rig is still making a noise. I actually replaced all of the gears in the front gear box. It sounds better but does not sound right.