Hi, i have a 2002 toyota tundra v8. it has 170k miles. two weeks ago the the transmission/torque converter were replaced (total failure two weeks ago). it has been driving extremely well these last two weeks since the replacement was done. however today the truck started to shudder. the shuddering happens in reverse and drive, not in park/neutral. you can feel the whole truck shake (not all the time, but maybe every 5-20 seconds). idling at a stop light while in drive is probably the worst. the transmission is naturally under warranty and i will be taking in thur morning. however i was wondering if it could be something else. i checked for codes with my obd-ii reader, there are none. vacuum hoses looked good too. i don't have equipment to check for clogged cat converter. atf fluid looks new (should be) and level is correct. also, i do not believe it to be bad gas as the last fill-up was a week ago and it has been fine until today (have about a qtr of a tank left). is it possible the dealer put the wrong atf in it? the atf changed from 2002 (dexron-ii) to 2003 (toyota type t-iv). this is a toyota re-manufactured unit. also, any of you think lubeguard (platinum) works? and if it does work, does it work forever (or until you change the fluid) or just a very short term fix. thanks!