Heat Pumps and Electric Heating - Air Handler making noise

I just had a Goodman heat pump (Model CPE36-1A) replaced with a brand new Goodman CPLE36-1C due compressor failure in the old unit. The technician also installed a filter dryer which wasn't in the old unit I believe because I asked him about that since I didn't see one like that on the old one. The replacement was made two days ago (on Friday Feb 24) and now (Sunday Feb 26) the air handler is making a terrible grinding noise. I'm frankly tired of having to pay service fees for every time the technician comes out (I just had to pay two hours worth, $144, just to let him tell me that the compressor died). Could this grinding noise in the air handler be the result of something that the technician did? Accidentally hooked up something wrong maybe? Or is it just a coincidence? Everything seems to work fine as far as heating is concerned. He also replaced the old Janitrol thermostat with a new digital Carrier model (don't know if this information is helpful, but thought I'd mention it).
Other work done on the system recently was replacement of a 150 degree Goodman limit in the air handler and several parts in the old heat pump (condenser fan motor, capacitor, and defrost board).

Thanks for any help in advance!

Sacha

If all he replaced was the outdoor section you.ve probably got a coincicence going on. the filter drier he installed kinda shows me he was doing the job right. It's always good practice to install a filter drier on a replacement like that.

Thanks for the quick reply.

Do you have any idea what could be the cause of the noise?

Thanks,
Sacha

Without being there to look at it it's tough.