01, 48k, stock

whenever the car has more than 1/2 throttle and shifts between 2500 and 5500 rpm (in both auto and e-shift), a rattle (almost sounds like a ping/knock that an engine will make) is audible.

if i let it shift at or near redline by itself or with the e-shift, no noise. if it is given less than 1/2 throttle, no noise.

any idea what this could be? it could be a loose heat shield or something, i guess, but nothing looked out of place. i may just bring it to the dealer, but i hate bringing my cars to the dealer, so i'd like to avoid that.

thanks

 

bring it to the dealer and have them replace the transmission fluid......sounds as if that wasnt done when it should have been at the 30k service

also on the engine, whats the history of the car? how often oil changes done?? what octane gas is used?

 

I purchased the car w/44k as a lease return, car came from a lexus auction, one owner. I do not know the history beyond that.

I changed the oil/filter (5w30 syntec) about 1k ago, the tranny fluid is still red, looks new. I do have new type 4 fluid in the garage, but I did not think it needed to be changed...

i use 91-93 octane.

I don't have a shop manual for the car yet, so what is required when changing the fluid? I read something about dropping the pan and replacing the filter... is that necessary with every change?

Thanks for your help.