2011 Prius II automatic transmission change...

Many Prius owners change the fluid at 60,000 miles.

 

Toyota has no official change interval.

My personal opinion, change at 30,000 miles, 90,000 miles and then every 90,000 miles

 

After reading the other thread on transmission service, I will have mine changed at 10,000 then probably 50,000.

 

Many prius owners never change it and never have problems, some are worried and change it about every 60k. It's up to you. It alwaysw a good idea to check for leaks and I pull the fill plug and check the level of the fluid every oil change. Old fluid= no harm low or no fluid= 6 grand in repairs.

 

You go through leveling the car out and checking the fluid level at the fill plug every oil change? Wow, I'd be ok checking it once maybe, then only if any leaks detected at the drain plug or anywhere near the transaxle.

SCH-I535

 

It appears that high ambient temps will contribute to early ATF breakdown much faster than mileage or age. I just changed my 2010 at 78K miles it spent the first two years in Tuscon Az till about 30K miles then the remainder in Alaska. My fluid appeared to be in pretty good shape though I didn't do a UOA. If I lived in a hot climate I'd say 30K is safe but not overkill. In a place like Alaska 100K would likely be fine.

 

Could just be that the first change looks more knackered, due to manufacture debris, gasket material, gears seating, and so on. We've not gone anywhere, first change at 15000 kms looked decidedly darker, second change at 40000 kms looked like overkill, the stuff looked near-new.

 

I don't level the car when I do an oil change. I drive it up ramps and just lay under the car. I did level it when I changed the tans fluid but it made no difference in the fluid level, maybe 1-2 mm but not enough to worry. It takes me an extra 60 seconds to pull the trans fill plug and check the fluid level and to close the drain plug when I already under there changing the oil. I think it's worth my time considering oil change is almost every 10000 miles.

 

So you're saying it's probably Ok to drain and fill the transaxle fluid with only the front wheels on ramps, and not worrying about leveling the rear?

That would make the drain/fill much easier.

SCH-I535

 

The drain bolt is towards the back of car. Seems to me if you fill (or check) thus the level's gonna be on the low side, though maybe still within spec range.

My 2 cents, I wouldn't check if there's no visible leakage, save putting wear-and-tear on the bolt and washer.

 

You mean the fill bolt?

SCH-I535

 

Yeah

 

Easiest way, I guess is to change the fluid with the front wheels on the ramps, jack up the rear to level it and to replace the fill plug, and then lower the rear, and so on.

 

I have a sloped driveway. I might try driving the front up the ramps with the rear wheels on the ground on the high side of the driveway. Rear wheels will be chocked for safety of course.

SCH-I535

 

I filled with car level. Then drove the car and jacked it up and got it level again fluid was still full, slowly coming out of drain plug, I lowered the rear end first and no more fluid came out. If what your saying was true it will start to spill fluid out when I lowered the rear end of the car with the fill plug out. If the fill plug wears out from me removing and checking it 15 times over 150,000 miles I will not buy another Toyota.

 

Sounds like you can drain and fill with just the front raised. Put 1 gal in and off you go. I'm guessing the fill/drain plugs are good for as many discharge/charge cycles as the traction battery. Though I have no idea how many that actually is.

 

The 10mm hex sockets of the fill and drain plugs have got to slip and wallow out with multiple loosening and tightening, especially if the tip of the Allen wrench is not fully inserted square.

Toyota used a shallow 24mm hex head fill plug on the Generation II. That apparently is still NOT the answer as the socket wrench also slips on the shallow hex and rounds the corners.

I am doing an extensive search to find fill and drain plugs that will be acceptable for multiple fill and drain cycles.

I also see that the lower drain plug, although identical in thread pitch and head to the fill plug, has what appears to be a ceramic magnet to catch iron particles worn off of the gears of the transmission.

I have sourced one plug with a full height 19mm hex on the head, which will definitely be conducive to longevity.

Instead of using a ceramic magnet, I intend to bore the center of the plug out concentrically in my machinist lath to fit in a neodymium N45 magnet, which I will press and lock in with Green #640 Loctite (the grade used to lock in cylinder liners into engine blocks).

I see no problem with the aluminum threads in the transaxle case, if the plugs are started and run down by hand and NOT over torqued.

This sounds like overkill, but from my experience in the aerospace industry, I think that it is worth it.