Originally Posted by Däs Schmoo
Manually shifting an automatic is a very bad idea. Your transmission will fail prematurely if you do that. Redlining an automatic tranny will cause the fluid in the torque converter to heat up to dangerous levels and eventually distroy the tranny.
You won't get much out of bolt-ons from an automatic LS motor. Mostly, it will just be a psychosomatic increase in power because of the extra noise that is produced. You would be lucky to pick up 5 hp out of all that.
Remember, noise does not equal power.
I'm thinking the trannies are quite durable. Back in 1998 I was home on leave from the Army and I was checking out my bros. new car, well to him. It was a 97 RS. I think...anyways, that fucker wanted to race me in my 89zc powered Integra and all he had was an intake. Dude put it neutral, pedal to the fl. and dropped it into one. I thought the tranny was dropped out right there. He did it 5 times that night even after I warned him about that. Well 210k miles later he is still driving on that same tranny, so I don't know. Compared to that abuse, bumping may be ok. But yeah, not a lot can happen performance wise w/what he has to work with.