~TABASCO~
RIDE ON ADV is what I do !
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
2014 Site Supporter
Vendor
the end is totally flat and smooth. But the internal 'side' might have that cup to hold the internal spring. I had NO IDEA that end cap could possibly come off... ( I still don't know if that's even possible ) but the size / shape / and you having an aftermarket MCCT installed suggest that this "might" be the culprit.Do you have an "end on" photo of those units?
No matter the case, you might want to drop the pan soon and see if the other half it sitting down there. Easy job with a new gasket.