Auto Transmission Fluid

I have a 2007 Hyundai Accent (OK, don’t laugh, it gets 35mpg!) The manual says to change the Transmission fluid at 105K under normal conditions. In harsh conditions, such as mountain driving, it says change fluid every 30K. I live in East Kentucky and we have large hills but I wouldn’t call them Mountains. Should I change the fluid every 105K or 30K? Any suggestions? Is synthetic oil or transmission fluid worth the extra costs?

Unless it gets real dusty where you drive, I’d say change the tranny fluid/filter every 50k unless you are towing(?) a small trailer around as well.

Using synthetic anything is up to you. What does your owners manual recommend?

If you’re going to change the fluid use SPIII fluid from your Hyundai dealer. I’d change it sometime between 30-50k no matter what. Hyundai probably also recommends 7500 mile oil changes which I wouldn’t wait that long for. If you’re doing it yourself the change will run you $30-$40 depending on whether or not you have a drain plug and have to change a gasket and filter. Spending less than $50 is good insurance!

Change ATF every 25-30k miles regardless of what the owners manual says.


I’d do a drain and fill every 30k-50k, not a flush.

It’s hard to picture your exact terrain, but let me ask a few questions. When you’re going downhill, do you frequently need to downshift to keep your speed under control? When you’re going uphill, does the transmission need to downshift more than one gear to keep you moving? That’s my guess at what would be considered “mountain driving”.

If you feel you’re somewhere between normal driving and mountain driving, then consider changing it around 50,000 miles as a compromise. A simple fluid change shouldn’t be that expensive.

I change my trans fluid on my 05 camry and 04 honda every 9-10K. honda doesn’t have a filter but I changed the camry one once at 56K or so. change my oil at 2-2.5K now (never more than 3K). Overkill, yes. Peace of mind. Yes

Thanks to everyone for the sound advice and taking time to reply. I’ll change the fluid at 30K and not worry about it!