Taz 6 Dual extruder v3 stripping filament

I took over my high school’s makerspace and was inherited two lulzbot taz 6’s. While I am familiar with CAD design and printing with a 3D printer, I am fairly new at troubleshooting printers. After working with students for a few months, I decided to upgrade one to the dual extruder v3 to allow us to use dissolvable supports or dual colors.
Test prints came out fine using the dissolvable filament. I was able to make interlocking rings with dissolvable supports, and print a little multicolor cube. Then the printer started having issues, especially with larger surface area prints. Even making the raft the material comes out stringy (tried both nozzles together and each nozzle independently).

I am noticing a lot of filament stripping near the idler gear (checked tensions and they are correct). When the filament is inserted, the idler arm is not fully setting

I figured this is causing some of the problems. I thought that it might be an issue with how the filament naturally curves away or with the head, so tried a variety of spool locations to no avail.

In addition, it has become extremely challenging to even get the filament inserted following all of the instructions on the manual. If I manage to get the filament inserted in a normal PLA filament change, I can turn the gear a bit to help feed/ extrude the filament before it becomes difficult to turn and the filament stops feeding. I then initiate the end of the filament change sequence. The gear rotates but the filament still does not feed through.

Sorry, there is a lot there. I am new to trying to trouble shoot 3D printers and am hoping for some advice, since we have been done to 1 printer since Winter Break.

I had similar problems. I guess testing different reel locations rules out tension in the filament. Try cleaning teeth on the extruder and also check nozzle temperature manually. You can’t push filament through a cold nozzle