Hello, I currently own a 2009 Gmc 3500 with 182k on it. I recently had the check engine light with the following codes p0708, p0706, p0894, and p2669. The indicator on the dash for gear selection also disappeared . The truck shifts terribly when starting from stopped and intermittently loses power, worse in reverse, but seems to run fine at higher speeds. I changed the external nsbu on my 03 sierra for the same reasons and it fixed that problem. I’m concerned with changing the IMS on my 09 as I am reading that these rarely fail because they are internal and it sounds like the TCM causes a lot of problems along these lines in these years?. Any help would be appreciated!