I recently purchased a preowned 2020 Blazer 1LT with 97,000 miles. According to the manual, the transmission fluid should have been changed at 74,000 miles and again at 144,000. I called the dealership where I bought it, and they confirmed no transmission service was done there. I also contacted the service department that previously maintained the vehicle, but they had no record of a transmission service either. So, I doubt it was ever done. I plan to have it changed, but I’ve heard that if the fluid hasn’t been regularly changed, it might cause more issues. I’m currently at 98,750 miles and wondering if it would be a mistake to have a transmission shop do the change. I don’t want to go in with minor issues and leave with bigger ones. From what I can tell, there are no problem,no error codes. There might be a slight delay shifting into park, but that could just be me being paranoid. Any advice from mechanics would be helpful. Also, the dealership mentioned that as long as I keep up with maintenance, their warranty covers “anything oil touches.” Not sure how much truth there is to that or what it really covers.
There’s absolutely nothing wrong with performing a drain and fill.
I did it myself. It was really straightforward; not having a dipstick was a new experience for me. The vehicle actually ran much smoother after the drain and flush.
I’m not a mechanic, but I think your concern might be that a flush could dislodge sludge and cause problems. If that’s the case, you don’t need to do a full flush. Instead, you could just drain the fluid, change the filter, and then top up the fluid. This approach carries minimal risk because you’re essentially just adding new fluid. It’s important to address the transmission fluid since it does break down over time.
I’m not certain if it’s exactly the same situation, but we recently dealt with a couple of different dealers regarding the recommended transmission services for our Corvette. The dealer we liked and trusted was pushing a recommended service costing over $2,000, which seemed excessive given that the car is mostly a daily driver for 2/3 of the year and not driven aggressively. This recommendation also differed from GM’s suggested service for 22,500 miles. They were insistent on this service when he picked up the car after a warranty tire repair. It felt off, so he called another nearby Chevy dealer. They quoted around $800 for the full recommended service but noted from the records that it might not be necessary. They had him bring in the car, plugged it into their system, and it only showed a $220 service recommended by GM. So, it might be a good idea to specifically ask them to plug the vehicle into their system to see the exact recommendations for warranty compliance.
I stick to my maintenance schedule, and the second time I went for a transmission flush, they refused to do it until they confirmed it had been done previously.
So, this reaction is quite common. Just doing a drain and fill is much cheaper.