It really is this simple:
1) NEVER, NEVER, NEVER FLUSH A TRANSMISSION**
2) DRAIN & FILL IS NECESSARY AND APPROPRIATE
Service interval can vary depending on your usage. something used around town is going to have a longer duty cycle than something that tows frequently. Current manufacturer guidelines for nearly all transmissions are "lifetime" filters and fluids, which if you look at the small print is defined as anywhere from 100k to 150k based on the vehicle. Point being, "lifetime" fluids doesn't actually mean forever.
For my fleet, I drop the pan and change the filter for the first time anywhere between 60k and 100k (depends on the vehicle) and will do a series of 4-5 drain/fill in one day to get 90-95% of the fluid changed. From there I will do one drain/fill every 10-15k miles to keep the fluid fresh.
I use Maxlife ATF in everything that calls for ATF. I even put it into my Expy's 6r75, although many here would caution against that.
**caveat: one time my idiot nephew put a bottle of Dexcool down the transmission dipstick tube of his Olds Aurora. We flushed the hell out of that transmission. Then sold the car as quickly as we possibly could.
1) NEVER, NEVER, NEVER FLUSH A TRANSMISSION**
2) DRAIN & FILL IS NECESSARY AND APPROPRIATE
Service interval can vary depending on your usage. something used around town is going to have a longer duty cycle than something that tows frequently. Current manufacturer guidelines for nearly all transmissions are "lifetime" filters and fluids, which if you look at the small print is defined as anywhere from 100k to 150k based on the vehicle. Point being, "lifetime" fluids doesn't actually mean forever.
For my fleet, I drop the pan and change the filter for the first time anywhere between 60k and 100k (depends on the vehicle) and will do a series of 4-5 drain/fill in one day to get 90-95% of the fluid changed. From there I will do one drain/fill every 10-15k miles to keep the fluid fresh.
I use Maxlife ATF in everything that calls for ATF. I even put it into my Expy's 6r75, although many here would caution against that.
**caveat: one time my idiot nephew put a bottle of Dexcool down the transmission dipstick tube of his Olds Aurora. We flushed the hell out of that transmission. Then sold the car as quickly as we possibly could.
