Changing CVT Fluid at high miles

I have a 2005 Prius and my wife got it at 183k and I changed it at 200k. I'm at 238k now but just my luck, 2 cells in the hybrid battery are dead so it's sitting. I assumed the previous owners changed the CVT fluid and changed it. it wasn't tough to do if you have 4 jack stands and a concrete driveway.

 

It will not harm these transmissions like it presumably would a high miles "regular" automatic trans. In "essence", it's basically just like a manual "gearbox" drain and fill.

 

I have lots of good news!
It is never too late to change the ATF WS, it is an easy DIY job, and can be a cheap professional service.
I would do it every 100,000 miles.

There are automatic transmissions with clutches, and tiny passages that may react badly to new ATF. The Prius has no clutches in the Transaxle and no small passages, either.
(Also no torque converter so you don't need a flush)

Starting at about 4:50 he goes over what can go wrong. The Prius transaxle has no internal clutches. it has no Valve body.

None of the reasons he discusses apply to the Prius.

The Prius uses ATF WS, you can get it and two washers at your Dealer, or online.

 

Further regarding "4 jack stands": you want the car to be level when refilling. Stick with Toyota ATF WS fluid, 4 quarts should suffice.

Unfortunately 2nd gen Repair Manual does not include a fluid change instruction. (Hey, who would want to do that?...) But, attached is the fluid level check instruction, which at least gives the torque value for the fill bolt. Couldn't go far wrong to use the same value (29 ft/lb) for both fill and drain bolt. Also, a good idea to change both bolt washers; the dealership parts department should be able to sort that out.

All of this assumes you will DIY. If you're going to get it done, say by dealership, it should not be over $100. If you get a song-and-dance about it being complicated, try other dealerships, and/or an independent mechanic. You basically drain it (drains about 90%), and refill, and proper level is when it starts coming back out. Nothing could be simpler.

The simplest way to fill is a funnel and hose from above.

One or both of the bolts may be socket head cap screw, require a 10 mm Allen Key style "socket".

 

Just jack up the front as high as you can get it and put in 4 quarts.
3 times on mine so far.

Make sure you take off the fill bolt first it may require a breaker bar it’s very very tight from the factory,
Then once the fill is off remove the big dump bolt and clean its magnet.

Since the car is high up I clean the ac under dash evap coil also that uses a can of
Koolit from Amazon that connects to the underside condensate drip tube.