It doesn't have to be continuous and not sure where the laughing monkeys or barrel of monkeys comes from as it doesn't sound anything like laughing monkeys? It sounds more like belt slippage and can come or go be continuous or intermittent.
As a precaution you should change it ASAP as its not good to have "or suspect" OPDA noise because it can be catastrophic to the gear on the cam shaft that drives it causing the oil pump not to work.
If it was built after Feb 2006 the issue was fixed or semi fixed? but I think the fix maybe did more than just prolonged the life a bit for a "quick fix" given so many if not the vast majority have all done over 100K miles in 16 plus years.
The 2005 and very early 2006 that started to squeal while still under warranty caused the panic and stigma that some TJ enthusiasts may have blown out of proportion given any component that starts to fail after 16 years and over 100K is just another worn part that needs replacing.
2005 and 2006 are very common years for TJ,s in Australia because the Dollar was parity so a 2005/ 2006 new was a fair bit cheaper than a 1999 -2004 and the reason we have so many Golden Eagles and 65th models, Most Australian TJ,s are low mileage compared to those in US and OPDA failure has never seemed to be a major issue.
New OPDA is as cheap as a quality coil rail and 6 plugs so can be changed just as frequently.
thanks for the information, I did change it out, had to go with Dorman. the old one looked good with some wearing on the gear but to be expected after 100,000 miles. I am having issue with getting the P0016 code since I put the new OPDA in. I did use the sensor from the old OPDA but still got the code, so I swapped to the new sensor and still coded. made some minor adjustments to the OPDA position but no luck. Any tips as to now to dial in to get the code to clear out. the OPDA was not the source of my squeal, to me it sounds like it is coming from under the front seat area around the transfer case area. but I only got one ear, so I will need to take the wife for a spin so she can help pin pt the area the sound is coming from.