Transmission Filter Change

Check out “The Car Care Nut” videos on YouTube. He is a Toyota Tech, and shows just how simple this is. Once you do, I would be surprised if you ever set foot in that dealership again.

 

There is no filter in the transmission. It's a simple drain and refill. The toughest part is getting the car level when refilling to set the fluid level.

Check out this video.

 

how do they figure such a wide range of cost?

 

The dealer is probably uninformed about how easy it is to change hybrid transaxle fluid and quoted the price for a regular late model automatic transmission fluid change which is the topic of this video.

 

I once had a Ford dealership tell me to change the transmission fluid it would cost $800, and 3 filters. The truck only had one, and the true cost should have been no more than $300. When I called them on the outrageous price, they backed down to 2 filters and $600! I guess they figured as long as I didn’t know my truck they could claim and charge anything. I suspect this dealership is playing the same game. There isn’t a Toyota dealership in the country that doesn’t know Toyota’s hybrid system.

 

You are a lot more confident than I am. Check out this long thread that should have cost the owner no more than $300 for an SST.

My Prius dead again, with techstream this time. | PriusChat

The dealer's ineptitude cost him nearly $1,000 and days whitout his car and aggravation.

 

Changing the fluid on a Gen 3 is easier that I thought when I first changed it by removing the whole engine cover. I'd explore this option for the Gen 4, too.

There is a cutout in the undercover right under the drain plug for the fluid to drain out as shown in this photo that I took. If there is none on the Gen 4, I'd cut one out with a hole saw right under the drain plug, You can either leave it open like that on the Gen 3 or cover it with the appropriate hole plug.



Both the drain and fill plugs are easily removed from the opening exposed by lowering the oil change door as shown in this captioned photo.



All you need is a 12 inch extension for your 10mm hex bit.

Filling is easy using this extension funnel available at Walmart.

 

Changing transmission fluid is significantly less complicated and requires a lot less diagnostic capabilities than that situation. My comment was directed at their basic knowledge of the system, NOT their ability and skills at diagnosing complex problems.
If this OP actually has a dealership that doesn’t even have basic knowledge of the system then they would be wise to contact Toyota directly.

 

Changing transaxle fluid on 2nd through 4th gen Prius is VERY straightforward, on par with an oil change. The dealership's service writers are idiots, to put it politely. The cost through a dealership should be around $100, at most. Still, if they're telling you all this nonsense, I wouldn't trust their competence, or honesty.

The drill:

1. raise the whole car, level (level is necessary to achieve correct fill level).
2. Remove fill bolt, then drain bolt, with fluid catch basin of some sort, obviously.
3. Reinstall drain bolt (with new washer preferably).
4. Add Toyota ATF WS fluid till at the fill hole, till it starts coming back out. (A funnel and about 3 foot hose extension from above, snaked down through the engine bay, is simplest. Have an assistant doing the pouring make this easier. It'll take about 3.5 quarts, so go slow as you approach that volume added.)
5. Reinstall fill bolt.

Repair Manual Excerpt attached. There's a lot of gobblygook about temporarily installing bolts. I think the engineers are obsessing about the fluid's exposure to air/humidity being minimized. I'd say just don't dawdle, and use only fluid from freshly opened bottles, and don't save the left-over for next time.

 

37 ft lbs is too much. I'd use 29 which is specified for the Gen 3. The Gen 3 repair manual is not embelished and much easier to understand. It is attached here.

 

I was hoping you would chime in . There were some changes made to the Gen4 that influence a lot of the specs. And considering the cost of a damaged transmission, I have a strong tendency to follow the engineers who are privileged to that information.

 

Yeah funny that they bumped the torque value; it takes oomph loosening the bolts even at 29 ft/lbs.

BTW, if DIY’ing: the fill/drain bolts are socket head cap screw style. You need a male 10 mm hex driver. You can buy them in sets fairly cheap; Stanley makes one. Don’t just use an L-shaped Allen Key and cheater bar; do it right.

 

I am an aircraft technician and structual engineer. The plug does not hold anything to the aluminum casting. Using a higher torque with a steel threaded plug into aluminum will more likely apply a higher load to the threads, which are basically a lever arm rocking on the root of those threads as the fulcrum. Damaging the aluminum threads in the transmission case would be a more severe problem.

The plug is held on by both the tension on the threads and the friction on both surfaces of the crush washer. Een at 20 ft lbs, it will not likely self loosen. The only reason to go 29 ft lbs is for fluid tight sealing which can even be achieved at a lower torque,

 

So, you are probably the one to answer this question then, what is the actual (not just generic such as aluminum) casing made up of. Looking for a precise answer here to help us (or at least me), decide if perhaps I shouldn’t be trusting an engineering and design group who has been working on Toyotas for a significant portion of a century, and has managed to produce two models (of various configurations) that have a reliability rating beyond any other manufacturer. And, while you are at it, are you willing to sign what ever court documents are necessary to stipulate that if I (and others) follow your advice and it results in a failure of the components of the Gen4 transmission you will pay the tab?

 

Most all professional service technicians don't even use a torque wrench to tighten these plugs.

I'd advise you consult with the Toyota Corporation for this information or contract an enginerring firm to conduct the study you claim interest in. At present I am not interested in this type of consulation at this time and stated basic engineering principles.

Toyota obviously keeps most of the data you request as a proprietary trade secret, only to reveal it if ordered as discovery in a law suit. My interest obviously does not go that far.

 

OK. Thanks anyway. Regarding the “most all professional”: if I have a work order indicating that they indeed performed the service and problem later developed with the transmission that was the result of their failure to follow procedure, a new transmission would be the least that I would most likely be receiving.

 

^

 

If you need just the 10mm hex bit socket, it is available at any Home Depot for no more than $3 including sales tax.

Husky 3/8 in. Drive 10 mm Hex Bit Socket H3DHBS10MM

 

I called two local dealers, one said every 60,000 miles and the other said between 80 to 100,000 miles. They wanted an insane amount to change it considering it's about a 15 minute job. Dump and fill, not rocket science. I can't see where the fluid really needs to be changed at all unless heat from the motors and alternator are breaking down the transmission fluid. The CVT does not have any clutch packs to generate heat like a normal automatic transmission. It would be interesting to see how hot the Prius transmission gets from normal or hiway driving. I just might check it with my laser thermometer next time to see how hot the case gets.