I have a th400 with a B&M 3000 stall, B&M cooler, and a shift improver kit. Yesterday in town my trans started having funny shifting issues. 1-2 seems well enough, except its softer than usual, but 2-3 takes a good half second longer and feels like it is slipping a little while it shifts. I checked fluid right after it happened. It was half a quart low from a leak, but the fluid looked good. I thought it might have been a vacuum issue, but the hose going down to the trans is fairly new and held pressure blowing through it. It's still doing it today and I'm not sure whats up. anbody with ideas?

update. I threw in a big pint of seaform Trans Tune and it doesnt seem to have changed much

the clutches for third(direct) are probably on their way out. you might get a little better if you install a transgo shift kit as it holds third three times as hard. probably a crutch that might not work though. if you feel like it's worth trying atleast if you have to rebuild it the kit would already be in there. you could also increase pump pressure as a crutch by installing another horse shoe clip on the pressure regulator valve in the pump (you could accomplish this with the pan off) or a stiffer shift kit pump spring (again with the pan off).

*sigh* I was hoping that wasnt it lol

thanks for the input ed