I replaced my TH400 with a 2004R spring of 2020 behind a stout 455 (about 575 hp and tq). No problems after two summers but not tracked. I used Extreme Automatic's stage 2 for ease of mind. If you already have the 200 maybe touch base with Lonnie at Extreme (or another reputable source) to check off some potential sources of problems. Different animal the GN and the 455. Also, the 2004R is an easy install.
|