We were burning in a new set of 3 CIM Ball Shifters from Vex Pro recently, and almost all of them produce a loud clicking noise when in high gear. See attached video, where the clicking noise is present at the beginning, but then stops after it shifts to low gear.
The gearboxes are using the 2.65x Spread. The 3rd stage is not attached. They are powered by 2 CIM motors.
This is happening with 5 out of the 6 new 3 CIM ball shifters I have received. Initial inspection of the gearboxes disassembly shows no signs of damage to the interior.
Any idea what might be causing this? It is cause for worry, or should this be expected? Thanks in advance.
Yep, all the gearboxes have been greased up. We began the process of cleaning them out and regressing them to see if that potentially fixes the issue, but won’t know the result until next meeting.
I think we had a similar, though quieter, noise from a 3cim shifter last year. Can’t remember if it turned out to be a misaligned screw or a forgotten retaining clip, but after careful reassembly the sound vanished.
We will disassemble them again and do a complete reassembly to make sure there isn’t anything missing. Should only be an issue with the higher gear set, so I will make sure nothing is rubbing up against anything.
I suspect this isn’t the source of the issue though, since it has happened on 5 of the 6 gearboxes I have worked with so far, across 2 different teams.
We had this same issue on our 2016 robot, and we never figured out what was causing this. We had a theory it was due to low pressure on the pancake cylinder (we ran them at like 40 psi i think, since we had an offboard compressor?) but never tested that theory.
I’ve noticed this sound when the gear is not fully engaged, not sure if that’s what’s happening hear but if there is no air behind the cylinder this could be the issue.
Adding a pneumatic system didn’t seem to help, and might’ve made the clicking worse. At least now it’s obvious that the high gear is actually engaging, but the clicking is still there. Planning on doing a full rebuild tomorrow to try and figure out where the noise is coming from. Emailed Vexpro support about the issue. Will report back with any findings.
Been awhile since i’ve worn this hat, but double check your shifter cylinder coupler to the shift shaft.
I’d bet that is in the wrong location and not enabling the plunger to make it to the correct location.
working with these for years, make sure there is nothing inside, make sure they are not over tightened. sometimes the kids grab the wrong bolt and put one in that is too long, also you NEED 60 PSI to shift, if not you get a very loud clicking.
So after a long while of messing around with it, we think we’ve found the source of the clicking.
It appears than when the gearbox is in high gear (i.e. the plunger is lowered), the balls in the low gear slot are too loose, enabling them to jostle around a lot more than I would assume they are supposed to. This leads to the loud clicking sound you hear in the above videos.
I don’t assume this is an huge issue. We will keep an eye on it as we run them on the practice bot and during the season. Will update this thread if any other issues come up.