Trouble printing with ABS

So I am just getting into printing with ABS. I got a couple of decent prints and then things started going wrong. The main problem seems to be with the extruder stepper motor assembly. I have to put extreme pressure on the filament to get it to grab it and send it to the hot end. Then after a little while, the stepper motor gear will dig into the filament enough to where it no longer grabs it. I saw a post with a similar problem which suggests that the speed settings are off, but I had two successful prints with the same settings. I loaded PLA back into the printer and it all worked fine. Could it possibly be just a bad spool of ABS? I tried slowing the print down by 25% and the problem persisted. I attached a file of the speed settings that I am using. I am also unclear whether I should be using the fan on the hot end. Any help is greatly appreciated.

I print my ABS max 40mm/sec personally. Also dont use a print cooling fan for ABS. PLA works great but not ABS.
Also what temp are you extruding at? I print ABS at 240c

I've tried 235 and 240, both with and without the hot end fan. I'll try slowing the speed down to 40 mm/sec. It's just strange that it worked fine for a couple prints at my current speeds.

Maybe you have to clean the nozzle?

Perhaps your hot end temperature measurement is off. Try 245C. Make sure that your hot end fan cools the hot end heatsink efficiently but doesn't blow on the print.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

I print the first layer at 250C then drop the hotend temp to 240C. Bed temp for the first layer is 128C, second layer is 120C, then I drop it in 5-10 degree increments to 105C. Changing filament brands usually means recalibrating temperatures.

There are temperature calibration videos on youtube and models on thingiverse that make it easy to dial in the correct temperatures.

When I print ABS my bed is 120 and my hot end is 265. Remember these are not calibrated temperatures, and I use print bit on the bed which requires some extra heat.