There isn't a way to "transfer" a type to a FAA certificate except at the private level on a 61.75 "based on" certificate. Since you already hold an ATP you can not get a 61.75 cert. So you have to complete a ground school and flight training per 61.157:
b) Aircraft type rating. Except as provided in paragraph (c) of this section, a person who applies for an aircraft type rating to be added to an airline transport pilot certificate or applies for a type rating to be concurrently completed with an airline transport pilot certificate:
(1) Must receive and log ground and flight training from an authorized instructor on the areas of operation under this section that apply to the aircraft type rating;
(2) Must receive a logbook endorsement from an authorized instructor that certifies the applicant completed the training on the areas of operation listed under paragraph (e) of this section that apply to the aircraft type rating; and
(3) Must perform the practical test in actual or simulated instrument conditions, except as provided under paragraph (g) of this section.
No where does the reg say how much ground school and flight training you have to have. Check with the sim center in Montreal to see if they have a short course they can run you through. I know a 142 school here in Texas that has foreign pilots current and qualified go through their upgrade class v. initial ground school. Four days of GS v. ten and I think it's 3 sims and a check v. 5+ the check.