Everyone has an opinion based on their experience and training and as for me I have always dropped the pan and ‘screen’ to service automatics. There is always a considerable amount of sludge made up of clutch and band friction material that I feel a critical need to clean out. And when a ‘screen’ is not available I have cleaned and reinstalled the old one. The fluch machines were becoming popular about 20 years ago and I wasn’t impressed so I continued with my proven old school service. Problems after service were extremely rare and the additive Trans-Medic always cleared those up quickly. Somewhere years ago I made it SOP to add that product whenever I serviced a transmission and as a result never had another complaint. But to each his own.
Everyone has an opinion based on their experience and training
Very well said, Rod. There is a clue there that Toyota has a drain plug and most of your “American” cars do not, thus the only way to change it is to drop the pan, unless you do the method which disconnects the pipe at the radiator and run it out that way. I do not want the mechanic of the moment disconnecting things on my car if I can help it. I worry enough when I do something to it.
If I were forced to drive a car with no drain plug, I would definitely have the pan dropped. No debate to it.
I am not like transmission man, I forget his i.d. But, I was wondering what the fluid currents are like in a transmission. All the power, and in some cars it is considerable, passes to the wheels only because of a large quantity of that fluid churning and flying around inside the transmission. At least, I think that is the case. If not, please correct me on that.
For some reason, a slightly off-topic story entered my mind. Some years ago, I read a tale that at one time Rolls Royce wanted to use GM transmissions in their cars. So, they bought some, and in line with their normal ways of doing things, tore one completely down, and polished every single part. The transmission would not even move the car. I cannot vouch for this story, only that I read it in a book at one time.
I recall that story Re Rolls-Royce also @irlandes. The attempt to blue print, port and polish the transmission resulted in failure so they let GM build a transmission for them using standard procedures. I believe that dates back several decades. BTW, R-R was usually one of the last manufacturers to adopt technological improvements. The brand’s reputation was built on mechanical overkill and redundence.
Yes, it was some time ago.
I compare it to top gun French chefs. It is not so important what it tastes like, but how it was made… Hee, hee.
@RodKNox Yes the GM Hydramatic as used in Olds and Cadillacs was the best on the market. Rolls Royce also gave up designing a proper air conditioning system and used a small Texas based company to do it for them using the best components. Your average British “Lord” was carefully not told that these "ex-colonial"s had a hand in building their favorite prestige car.
Its been 32,000 since my last pan drop so I have an appointment Thursday for pan drop and filter. 'Spose to be permanent full synthetic but I’m not listening. This one has no dip stick, no filler tube, etc. so has to be up on the hoist to fill it again. Another 5K and I’ll do the Acura with a drain plug.
Back to lawn mowers. The automatic hydraulic transmissions being used in 90% of the mowers now have been very troublesome. Some say that simple annual changes of the fluid can make a big difference-but no drain plug. In order to change fluid the trans has to come out and be disassembled. The Tuff Torq, the transmission manufacturer claimed that each mower manufacturer like Husquivarna, MTD, etc. were given the option of drain plugs for an extra 50 cents each. They all declined.
Maybe its the pendulum again that I am a firm believer in. We have moved so far to the throw away culture that now maybe its time to move back to a reasonable repair and maintenance culture. Walmart is in trouble and can’t lower prices any more so even they will need to start talking quality and longevity. Maybe I’m a dreamer.
If you are going to use a fluid exchange machine, I would recommend that you drop the pan and clean or replace the filter before using the machine, not after.
The ATF is being drawn from somewhere near the center bottom of the pan, it goes through the transmission to the heat exchanger in the radiator and then back to the pan near the edge. The fluid exchange machine is constantly diluting the old ATF, not replacing it.
That would be like if you had a swimming pool ad someone urinated in it. The pool cleaner wants to turn on the pump at one end of the pool to pump out the water while at the same time, replacing the water as it is pumped out with a garden hose at the other end. Just how long do you think this type of operation would need to run before you would get back into the pool?
If you have fresh ATF in the pan, then the exchange machine is actually flushing out the transmission completely because in most transmissions, once the fluid is picked up from the pan, it has to go through the heat exchanger before returning to the pan unless the high pressure bypass is tripped for some reason.
Be sure to use only the specified ATF for your transmission, no universal stuff.
In the swimming pool, if chlorinated water were in the pool, I wouldn’t leave in the first place. Remember I live in rural Mexico, hee, hee. A lot of the poor people wish they had drinking water that good.
I think I said above I use Mobil-1 synthetic ATF in my Sienna. The transmission seemed to work better when I started using it.
While I certainly do understand where you guys are coming from, with all the churning in the transmission anything that is in a place where it just sits there and doesn’t get stirred up after 218,000 miles probably doesn’t matter. So, I don’t care much. If it can get into the system and mess things up, one of two things happens.
The ATF looks dirty when you change it out, which mine does not. Or, it will be diluted so fine you can’t see it, but regular drain and add keeps it clean anyway.
One thing I have never seen is a detailed analysis if different brands of transmissions tend to run dirtier than others, or if there is more metal stuff running around in some brands than others.
Alex at Pharr Toyota told me they very seldom have transmission failures on Siennas. He is my SIL’s (son-in-law’s) old friend so I believe him.
I do know a cousin here in Mexico imported a late 90’s Yukon. I mentioned feeling a need for an automatic transmission because my size 13 (they call it 32 here) feet get tangled up so I do not want to be using a clutch pedal all the time.
He said automatics have a bad reputation for failing and it costs a lot when they do fail. I explained that most folks don’t know to change the ATF. We looked at the dipstick on the Yukon and it was dirty and smelly. Now he checks it and replaces the fluid and filter, and it stays clean.