One of the potential projects on my old car is a oil change in the tranny. I'm talking drain and refill, not a complete flush. In other threads I've read warnings about changing the tranny fluids on old cars with unknown service history - aparantly there is a known risk for problems after a change here.

My car runs good and the tranny works flawlessly, but the car is 20 years and 200.000 km old, and I do not know when or even if the tranny has had a change... And I wanna perform this operation to learn.

What's the current consensus - is a drain and refill dangerous on a car like mine?

 

No.


use toyota t-iv trans fluid. you'll be fine.

 

I remember reading about draining a littke then adding little by little over time as not to "shock" the system.

I'm not positive what the correct way is. PureDrifterhas been doing this for quite a while so looks like you have the go ahead

 

It all depends on the service history of the transmission, if the transmission fluid was changed regularly, you are good to go, but if you think it the transmission fluid could be original, or it could have been like 150,000 km or over ~8 years ago since it was last changed, then you really can "shock" the system and cause a failure that is unnecessary.

The detergents and additives can break loose things you don't want to break loose! In another thread on Club Lexus right now, another fellow has what is likely to be a valve not operating correctly, and this could well be a result of his recent fluid change, it may well have broken away some buildup and that has become caught in the valve body and either blocked a passage or caused a valve to not open or close right.

So if you have no history on the car, I would drain and fill like a quart at a time, say every 2 months, to introduce the new fluid in over time, this will, in fact, eventually "flush" the system, just slowly and safely! Transmissions are too expensive to play roulette with!

Think about this: have you ever noticed that often you hear of a friend who had his fluid completed changed out on a transmission that had not been serviced in forever, and it often seems like within a few months he has some major problem with the transmission? - it seems like I hear this kind of sad story once a week almost!

 

I agree with LScowboy. the problem may be there already but may not be noticeable until the fluid is replaced. I personally would only do a full tranny line hookup and flush. it is a little pointless to drain and fill the pan as you will get but a fraction of fluid and still have old fluid in the torque converter, lines, rad etc. it would be like pouring out the top of a dirty cup of water, filling it 1/3 full of clean water. would you drink it?

 

sure! - if you do this enough times, then mathematically, you eventually have clean water! (and a transmission that still works! )

 

A normal drain and refill would be about 2 quarts at a time. Is that too much?

I do have history, but either unconclusive or no tranny oil change performed.

 

DO NOT DO A FLUSH!!!!!! You have about a 85% chance of blowing up your tranny with that kind of mileage on it. A drain and fill is the only way of doing it safely. I worked for years rebuilding tranny's and heard many horror stories of people doing flushes. just like LScowboy said, you'll break loose deposits, clog up passages, and cause more harm than good. Do a drain and fill! The only reason a shop tries to sell you a flush is because their mechanic hooks the car up, the machine does the work, and he is free to go perform more work on a different car. it saves them time, and makes them more money at the expense of your transmission.

 

Update: looked deeper into the service records and actually found a service done 6 years and 50.000 kms (30.000 miles) ago which included a tranny oil change performed at the authorized dealer (Toyota) in my town. This means the tranny oil change should be on schedule.

In conclusion - safe to do a drain and refill of the 2 liters. No complete flush.

Should I also drop the pan and clean/replace the filter or should I just leave that too?

This car is no beauty, but I like to work on it to actually do something with my hands other than fiddling with my computer.

 

yes, I would do the drain and fill for 2 quarts, and then wait 6 months and then pull the pan and change the filter and that change will yield at least 4 quarts out

reason: the amount that comes out is time dependent, so if you only have the drain hole open for like one or two minutes, you might get out 2.5 quarts, but if, for example, you left the drain plug out to drain all night for 24 hours, you may get 4 or more quarts out!

 

i did this method using 12 quarts of transferred ATF with no adverse affects on my transmission on my 97 with 135k.
http://www.lexls.com/tutorials/trans...ransflush.html

 

Thanks!

One more question from an amateur that has never performed this operation before - at what temperature should the tranny be when draining? I.e. should it be really cold, or driven to normal operating temperature? If it should be cold, how much can I drive it before draining?

Since I cannot do the change where I normally park, I have to drive it to the garage.. short way or long way?

 

as hot as possible, after a long drive would be great


I don't know what this means



I would strongly recommend you have a new drain bolt and drain bolt gasket that are both genuine Toyota from the dealership, and at least 4 quarts of T-IV, before you start. The drain bolt and drain bolt gasket are both recommended to be replaced when doing this and the pair is cheap at the dealership (around $5 total)

you need a new funnel that will fit the transmission dipstick tube, the transmission needs hospital cleanliness and that old funnel you have laying around is not squeaky clean like a new one (about $1 at most auto parts stores here in USA))

make sure when you refill the transmission, that you check for leaks at the drain plug frequently over the next few days, wipe the area dry so that old oil doesn't confuse ya!

use the dipstick cold mark for refilling to get it roughly right (transmission running in park) and then drive the car for 20 minute and the park on very level ground (transmission running in park) and use the hot mark to get it dead on.

It is better to be slightly over the hot (final) mark than below it. (like up to 2mm is OK)

 

correct you'll need a skinny funnel to fill the ATF through the dipstick as such.

 

Thanks all.