Took a 19/32 drill bit to make clearance in the 3 holes on each of the 2 housings, the gm holes are quite bigger than the new housing, there are 2 small metal pieces that you need to dig out old brittle gm housing and they look like mini cup holders, also take out a flat metal piece and add to the new one, you will need silicone grease to put on all your parts. Overall this product is nice, the coupler is nice but the opens on the red gear it does not fit, but it looks good. Very happy to have this product!!
This product was by far one of the best reproduction parts I have purchased in a long time. The only mod required was to open up the axle holes in the plastic. As other have complained about this I really like the fact that there is the option to adjust for component fluctuations of the original parts. I have done two seats now and would highly recommend this for anyone needing to service their seats. I would gladly rebuild anyones seat transmission using this part.