Scotty, I purchased a 2023 GMC Sierra 1500 3.0 Duramax this year. 15,000 miles. The manual only specifies transmission fluid change for “severe” conditions every 45,000 miles. The dealerships want to “flush” the transmission which scares me. Do you recommend dropping the pan (and cleaning the pan and magnet) and changing the filter as oppose to the flush? And if so how often (mile interval) should I change the fluid and filter? I’ve seen in your videos you recommend not flushing but I just want to be crystal clear and positive. Need this vehicle to last a few hundred thousand (used for work, construction). Thank you!!
I suggest you start by reading the transmission topic in our FAQ first.
fluid change for “severe” conditions
stop-and-go city driving is "severe"
Do you recommend dropping the pan (and cleaning the pan and magnet) and changing the filter as oppose to the flush?
yes. However ... the dealer may refuse to do it. Make sure you go over your warranty terms and conditions with a fine tooth comb, and ask for clarification where needed.
And if so how often (mile interval) should I change the fluid and filter?
Use the severe interval. If you do a lot of highway driving you can get away with doing it less often. Just monitor the fluid.
