So my Buick has been shuddering at around 35-40 and 55-60 and randomly stalling out when coming to a stop. I'm sure some of you have read my recent posts here regarding my issues. Anyway, I've been browsing around the internet, and came across a similar issue. The guy stated that disconnecting the wiring from the sensor mounted on the front of the transmission case can be helpful in diagnosing the problem and narrowing it down to a tcc solenoid issue. Well I went ahead and did that temporarily and my issues all went away. When I would typically feel the shuddering the check engine light comes on instead, and when the shuddering would go away typically the check engine light would go off. I think I've found my problem, so my question is, where can I find the parts to do this, and how complicated is it? Is it something I can do, and if not how much am I looking at. If anyone can point me in the right direction it would be greatly appreciated. Thanks.