Pin fell out from Traxxas CVD center shaft.

[danketchpel]

I was out bashing at lunch today and all of a sudden I lost my rear wheel drive. I have the Traxxas CVD center and axle shafts plus I just did the FLM diff upgrade kit so I'm thinking "the drive cup threaded pin must have come out". Nope, I flip the truck over and it's still in but the rear universal joint is just spinning inside with the red keeper ring in place. I pull back the boot and the pin drops out!

After closer inspection I see that the holes in the outer cup pin holes have worn significantly allowing the pin to move around. I greased those joints with silicone grease and the boots have staid on and aren't ripped. I've only put about a gallon on those shafts, I'm not impressed. Part of the reason I went with the Traxxas CVDs was their design was supposed to fix the pin falling out problem. The design works until things wear, then it fails.

I'm thinking to go to standard dogbones and be done with it. Is there a recommended dogbone kit for the standard chassis?

Anybody else lost the internal pin from these CVDs?

 

[Cupooterluvr]

The MIP CVD set has worked good for me for several months and about 3 gallons through em so far. I've had to replace the pins a couple times but only because they got bent (alot of power from the engine I got in there).

If you ever lose an MIP pin though you can easily replace it with some music wire, which any good LHS should have (mine did and I didn't know it... ask yours about it).

 

[danketchpel]

Here's a picture of the worn cup. You can see why the pin fell out.

 

[Cupooterluvr]

Oh, man, that's pretty bad. How long have you had those? If you've had em less than a year it's a reasonable bet that Traxxas will help you out with them. If not, I'd upgrade to the MIP CVD kit.

 

[danketchpel]

I'd go back to Traxxas except I see the flaw in the design. There is too much force applied to a small surface area, it's going to fail sooner or later. The other problem is that it doesn't take much wear to allow the pin to drop out. The design doesn't tolerate wear very well. It could be improved but it's not worth it for me to machine a new set of drive cups etc., I'd rather go with standard dogbones, they will work with the right materials, and they will tolerate much more wear before they actually fail.

My current plan is to have some SS shafts built by RC Alloys and use UE drive cups. I'm not sure about the brake hex yet.

I spoke with New Era and I think the their kit is probably the best option as far as a complete kit goes right now. They are working to upgrade it even further.

 

[GOTSPEED? (T-maxx)]

i had the same problem, try some lock-tite, it worked for me

 

[danketchpel]

I'm gonna toss 'em. I'm having a set of SS dogbones made by RC Alloys to use with a set of UE drive cups.