DIY Transmission Fluid Change?

Well...every post that mentioned refill qty was about 3.5 qts. I did drain it before leveling with the jack. Maybe that accounts for the higher fill qty.

 

Well, if its level, I suppose you cant overfill it since the fill hole is the fill line.

 

And, here's my transmission UOA after 32K:



And here's the virgin fluid report:

 

Just changed mine this weekend. I have 60K miles on mine. I figured I was a bit late after reading this thread but it's still better than doing it at 100K. Anyway, the most difficult part of the job was piecing together a funnel for the fill. I ended up picking up some heater hose at the auto parts store. I had to whittle down the end going into the fill hole a bit but once I got it in place it was very snug. Since I had six feet of hose it was fairly easy to route it along the right driveshaft and up the right side of the engine.

Removing the fill plug was a knuckle buster. I suppose since these plugs haven't been off since the car was built (late 2009) there was a bit of oxidation. When the fill plug finally let loose I sent the back of my hand flying into the edge of the oil pan, giving me a pretty good gash. Just a word of warning to anyone else who hasn't done this job yet.

Since I was doing the job myself, I intentionally overfilled a bit and let the excess drain out the fill plug. This was of course after carefully leveling the car. I took it for a test drive and all seems well.

 

Changed my ATF last night at 38,268 following Tumbleweed's protocol. I snaked the tube down the passenger side of the engine and over the passenger half-shaft into the fill hole, as I could not find a path behind the inverter.

I only got about 3.25 qts out and in. Old fluid was dark, but not burnt. No analysis purchased as I am cheap. Car was level. It seems silly there is no dipstick, but that is the new way, I suppose.

I bought 4 feet of clear tubing at Ace Hardware (~50cents/foot). And I bought a ATF tube at walmart that plugged into the tubing and screwed to the bottles. It has a cutoff (twist valve) at the bottle end. Worked fairly well, though a funnel in the tubing would do as well.

Drain and fill plugs seemed over-tight, but that always seems the case the first time. I replaced the crush washers.

Many thanks to Tumbleweed and others for the tips in this thread!

 

ok, I've got to ask the same type of questions I ask in the oil change threads...

Is there a documented problem with fluid-related failure of Prius transaxles at 60k, 100k even 200kmi?

There are millions of these cars on the road, the number of owners swapping transaxle fluid on these cars even at 100kmi must be negligible. The sample size here(on PC) is so small, how could you ever document any benefit to changing the fluid? It seems that this group got together and convinced each other that changing the transaxle fluid is obvious routine maintenance that all owners should be doing, but there can never be any proof that this is the case.

 

There are UOA's that have been compared with those of cars that do require changing the fluid.

But no, feel free to follow the recommended schedule (which includes inspecting the ATF). The implication of inspecting the fluid is that it might need changing if the inspection warrants.

The lack of a dipstick and the lack of clear and readily available criteria for replacement lead some to err on the side of caution. To each his own.

By the way, I'm a 10,000 mile oil change guy.

 

This is not proof:
No owner who has done the change has had a short in the Motor generators, no owner who has had a short in the Motor/Generators has done Transaxle fluid changes.

Beyond that you have to trust the oil analisys folks.

It is not like a sign will pop up and say "Should have changed the Transaxle fluid!" (I advise following Toyota's Oil Change Interval in the Prius)

 

I see it more as preventative mainenance. It may be a sealed system, but it is still metal on metal generating heat and friction. Its cheap and does no harm.

Toyota says 100k. I would be more comfortable with a first 10k to flush out all the manufacturing contaminants and break-in residue, and then a 100k between changes.

 

The fact that there is no dipstick is quite indicative that this is basically a sealed system that requires no maintenance (and that toyota doesn't see a need to even have consumers looking at).

The UOA's do not indicate the fluid needs changing, just that the fluid is degrading. If the fluid needs changing at 30kmi, and 99.9% of prius owners aren't doing it until 100k or beyond...then transaxles would be failing at a higher and higher rate as these cars approach 100kmi. Since you could never show that the TA fluid swap prevents failure, wouldn't you at least need to see a failure rate to be alarmed about in the first place?

There's a weird dichotomy here. People are very suspicious of Toyota service and their "upsell" of services. Yet Toyota's recommended maintenance is eliminating more and more routine service that they could easily charge for.(paraphrasing) "I hate that toyota tried to rip me off for air filters"...and in the next breath "I think I'll spend money changing fluids that don't really need to be replaced". Fluid needs to be changed at 30kmi...yet toyota doesn't even recommend changing it at 60kmi when their dealers could charge every prius owner $100 for it?

 

The minimum recommended maintenance schedule is not the mandatory maintenance schedule. It's a personal choice, and nobody's holding a grease gun to anybody's head to get them to change their ATF at an interval not of their choosing.

There are those that have the facilities, the desire, and the extra $30 to change tranny fluid early. Then there are those that have none of that. To each, their own.

 

See, here you are all but promising that swapping TA fluid prevents failure, when you cannot demonstrate this in any way. You cannot prove a negative. of course you cannot prove that an owner who did the oil swap WOULD have otherwise had a failure, as the incidence is extremely low. And you certainly can't say that "no owner who has had the short....has done TA fluid changes" as your sample size is only the few hundred cars represented here(out of the millions of these cars on the road). (I would propose that failures would be over-represented here as people may come to this site investigating a failure they've had.) Further, since the MG is housed in the transaxle are most MG failures directly related to fluid?

Obviously nobody is forced to swap fluids. But someone coming to this site for info may suddenly be freaked out about a problem that really may not exist.

 

OCD isn't always pretty. But changing oil or ATF early is more for peace of mind and getting to play with wrenches.

Anyone who perceives there may be an issue is wise to read up on it. Reading up on it would clearly show that early ATF changing is all about preventive maintenance. Preventive maintenance is not high on everybody's list, or even regular maintenance for some.

 

Yes, hill roll-down performance in cold weather as well as when the oil was warm was improved:

After the first transmission oil change, the car rolled significantly further than on the original oil:
2003 Prius - Cold Weather and Transaxle

Bob Wilson

 

No, I am only promising that it has in the past, I could be wrong anytime in the future. You mention our limited numbers but do not mention how many of our 'one time' posters came to describe some failure or another. Prius chat has many more 'members' than frequent members. Should you need proof, I explictly stated I was not offering proof.

Another example: I was feeling like my Gen 2 Prius was badly effected by wind at freeway speeds, so I installed a stiffenng plate. Since that time I have not noticed any darting at freeway speeds, it seems way more solid in its handling. But, it is entirely possible that it is all in my mind. I have no sceince showing tire deflection due to aerodynamic loading on the sides of my vehicle, I just drive it. If you prefer to think that no owner has had a transaxle failure who has changed the fluid is one of those 'baseball' statistics, feel free.

The amazing Bob Wilson offers glide down graphs, but my understanding is that fluid temps in a Gen 2 are just too high, I would purchase a transmission oil cooler if it were offered. (I suspect it would just be another item to drag on the ground, it is really packed under the hood)

 

Here are my costs to run the prius with no transaxle oil changes:

Fuel ~7 cents per mile
Tires, oil ~1 cent per mile
Insurance ~4.5 cents per mile

Here are my costs to run the prius with fresh transaxle oil every 30,000 miles:

Fuel ~7 cents per mile
Tires, oil and tranny fluid ~1 cent per mile (That's right, $30/30,000 miles = $0.001 per mile = rounding)
Insurance ~4.5 cents per mile

Given these values, I choose to change tranny fluid at 30,000 give or take. The recommended procedure is to inspect the fluid at 30,000 mile/36 month intervals. But if you prefer to inspect it without changing it, that is your choice. No one is trying to alarm people, but permanent fluid is something you seem to believe in while I do not.

 

I went in to Toyota of Fort Worth to pickup the ATF-WS and 2 washers. The parts guy calls in the service man to talk me out of it. $265 for them to change it.

 

Just go to Freeman.

 

Why would they talk you out of doing your own preventive maintenance? Aside from not getting $265, why would the parts man want to turn up his nose at selling you parts?

 

Double teaming!

Aside from not getting $265? That's precisely the reason.