I have added over 200,000 miles to my 2006 Buick LaCrosse since I bought it in 2007. It runs like a top and is reliable as the sunrise. Lest I get tied up in more cliches, let me get on with my question. My mechanic has recommended a transmission flush and fill. I have, however, been told by quite a few erstwhile mechanics that it is dangerous to flush the transmission on a high-mileage car, due to the risk of stirring up debris, rust, etc. and having it jam up the transmission. My mechanic says this is malarkey and I need to do it. Is he right, or is he just wanting my $200? Are my friends/relatives correct, and am I asking for trouble if I flush the transmission at this late date? (It has never been flushed before.)
You will get some disagreement between the “flush and fill” and the “drop the pan and change the filter” folks.
Since this transmission has NEVER been serviced, ignore your mechanic for now and have him drain the transmission, install a new filter, and inspect the pan. A flush cannot get the debris off the filter nor can he see any bad stuff that might be in the pan. If all goes well, I’d consider a flush and fill in about 20,000 miles after.
I agree. Normal service. Drain and filter.
First check the condition of the transmission fluid.
If it’s black and has a burnt odor, leave the transmission alone.
It’s too late.
Otherwise, drop the pan and check for any metal debris.
If any is found, put the pan back on, fill it with tranny fluid and cross you fingers.
Otherwise, change the filter, reinstall the pan, fill the tranny with fluid, connect the flush machine, start the engine, and let the pump within the transmission replace all the fluid.