For those who are first time owners of 2000+ Bonnevilles, does anyone recall what the tranny fluid level read on the dipstick prior to any tranny work? I'm trying to troubleshoot an intermittent but daily shuddering tranny occaisionally preceded by a slight slip and one weird thing seems that I thought the tranny fluid level was reading higher than the dipstick completely full mark (as delivered brand new from the dealer and prior to any tranny servicing). I'm a first time owner that never had any tranny work done and personally do nearly all the oil/filter changes and recently serviced the tranny (fluid/filter change). After just doing a filter/fluid change, I now experience this shuddering (sometimes preceded by an occaisional slip which mostly happens after an initial 15-20 minute drive). Feel like I'm pulling straws at the moment (wondering if there might be a dipstick issue).

Thanks for sharing. That'* wild! Used only Valvoline Dexron III/Mercon automatic transmission fluid. Seems like one heck of a coinkidink. Wish I drove the car more myself before servicing the tranny around 100K miles. Hoping for something silly or simple (like fluid level or flush/refill) rather than serious (like a $1,200+ rebuild job).

Overfilling seems to be a bit less of an issue for our trannies, as least if we follow Rogue'* advice. He recommends slight overfilling (half quart, i think) to take care of pump starving on sharp corners. However, some have had problems if they use synthetic, or synthetic blend transmission fluid. Which type did you use?

Used NON-synthetic and measured fluid with engine running on a level surface. Perhaps I'll try adding a bit more to about 1/2 quart over the FULL mark on the dipstick. Wasn't aware of the synthetic issue.