I talked to 2prosti (technical user) and he directed me to the clutch that needs WD-40 in back of the Imaging Unit. It's a bear to find, but you will find it at the rear of the axle that is adjacent to the yellow arrow that guides the Imaging Unit when you install it.
You have to take off the back cover (lots of screws), and even then you have to stand on your head to find the black clutch. Use the red tube on the WD-40 and spray VERY LIGHTLY, but be sure you remove all the consumables before you spray: Toner Cartridges, Fuser, Imaging Unit. You might foul one of them if the spray goes awry.
I had to spray two times; once after I printed 3 or 4 pages, and then again when the Jam at E occured.
When this clutch doesn't work properly, it can trigger Jams at "C", "D", "or "E".
It was magical, but it did take a bit of doing. Peter said that you might have to clean the grease out of the clutch, but it is extremely hard to get at it.
Hope this works for you, It was terrific for me. Barb