We’ve got a MakerBot Replicator 2x at work that causes all sorts of problems. Right now the toothed gear for the extruder is terrible, is there a good replacement / upgrade option for that part?
The one thing you should bear in mind when picking a replacement is if you can calibrate steps on that printer. If the gear is a larger diameter it will push more plastic and if smaller less. The gear is rounded to align the filament. I use a straight one and cut a Grove into the bearing at the back. So you may need to find one that meets your needs. Also there are upgrades on thingyverse you can print that may help apply enough pressure to the filament to stop it from slipping
100% I didn’t know they weren’t lined @Nathan_Walkner is right. You can buy the lined barrels and you won’t believe it’s the same printer
@Pete_Prodoehl
On our rep2x I solved the problem this way :
Drill a hole with 3.1mm diameter and 10mm depth in the barrel. Bought a ptfe liner with 3mm outer diameter and 2mm inner diameter (they are used for bicycles). Put a 10mm piece in the barrel and your problem is solved.
This way you can print without grinding your filament and pla also works way better. And because you’ve only added a 10mm long piece you are still able to print nylon and other high temperature filaments without burning your ptfe liner 
Also secure that the tension on the filament is correct. You can adjust this with the small grub screw on the top of your extruder.
Btw, I’ve also tried a 4mm ptfe line over the whole length. But the version I’ve described gives you way more flexibility regarding high temperature and high speed printing.
You’re going to want to use a genuine Makerbot drive gear so the filament path alignment doesn’t change due to diameter differences or bite depth.
Ptfe lined barrels cause a slew of other problems. Is your rep 2 using the original mk 7 setup with the Delrin plunger or the newer mk 8 style spring loaded tensioner? That is the part that actually Holds the filament onto the drive gear. Just google
Delrin plunger then mk 8 extruder and tell
Which one you have.
The only time you have a problem with ptfe lined barrels isbif you overheat them and the ptfe shrinks. That happened to me when the thermostor poped out and the printer notified me by smell. Other than that when it happened i tried to use the unlined barrel again while waiting for annew one but it was worse than windows8
@Wes_Makes_Stuff
The rep2x is mk8
@Pete_Prodoehl
Forgot to mention that some thermal compounds between the heatsinks and the Alu block also helps a little bit to reduce the Temperatur in the barrels.
And put a piece of thin cardboard between the stepper and the Alu block where the barrel is fixed.
Wow, thanks for all the feedback. Looks like making it more reliable is a bit of work. 