That idler gear looks like its bouncing around but I can't tell if the shaft is also jumping around
Did you pull that bearing cap?
I started gathering parts to redo my 68 but I'm no expert
What year is yours?
If you haven't seen it here is the parts list
https://graphicvillage.org/meritor/pb90172.pdf
There are some differences between the divorced (60-66) and married styles (67-69)
I got a bearing / seal list if you want it and the Meritor Kit 479 is the 60-66 style shims and gaskets. Torque king is the only source I could find for the 67-69 shims.