I have been hearing or feeling significant clunking when the thickness is setup at 3. How can I fix ghits?

bad CV? joints
feel them by hand, tire off ground. 1 by 1.

could be brakes... or bearings... check both and repost with more details if that doesnt fix.

Probably the center (carrier) bearing of the driveshaft or a CV joint at the rear axles. don-ohio (:^)

Your machine is complaining because it doesn't have the power to push through the layers of fabric. That clunking noise is the gears in the machine skipping and being sheered off (or it will be eventually) STOP!

If you feel that you need to continue... stop when it does this noise and use the HAND WHEEL. You'll also need to make sure that the presser foot remains level while going over thick seams.

Time to go see a transmission specialist.

Check and see if the Brake Pads were re-installed with all the hardware, ie, Anti-Rattle Clips, shims etc. if your pads are not secure in the Calipers it will cause the pads to rattle when you are driving in effect causing your brakes to make weird noises, ie, groaning, squealing, rattling.

could be a ball joint worn out or a spring coil broken

I am guessing this is when you have slowed down to just a crawl, mabey 5 - 10MPH or less. If this is the case the clunk you hear/feel is the transmission shifting in to first gear. There may be some issue with a universal joint on the driveshaft that amplifies the situation (have that checked out) If this seems to be the case I would not worry too much other than having the universal joints given a once over.

I hope this may have helped,
Tom

the clunk over bumps is either strut mounts or stabilizer end links. calipers are bad when you feel a pull when braking, or u notice excessive heat coming from your wheel

I have 3 2005 Malibus - 1 Maxx LT, 1 Sedan LT, and 1 Sedan LS. All three needed to have the steering rod replaced by 50K miles. You'd feel a muted clunk through the wheel when turning. The other light clunk issue I had with the Maxx was I hit a parking curb and it broke the lower radiator bracket. In certain bumps you'd feel a light clunk. A new $22 bracket fixed the issue and now I make sure I never pull too far into the spaces in the garage at work.