Tranny Flush at the local valvoline oil change place

Analog

Lifer
Jan 7, 2002
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I've dropped the pan on a few transmissions in my day, and changed the filter etc. I was told that the oil change places flush out all of the oil in the torque converter, which you can't do by dropping the pan. Somehow that is more beneficial than changing some of the tranny oil, but not replacing the filter (which they don't do).

Opinions?
 

MaxDepth

Diamond Member
Jun 12, 2001
8,757
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91
They have tranvestites at the quick change? Well, I guess they do call it a change...
 

iamwiz82

Lifer
Jan 10, 2001
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81
Depends on how many miles are on the tranny. Personally, I have never done it. How dirty is the filter?
 

radioouman

Diamond Member
Nov 4, 2002
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I agree that you can't remove all of the oil in the torque converter with a typical fluid change.

The tranny fluid's friction properties change due to heat, so you don't get all of those properties back when you only change half of the fluid.

Therefore, you can probably change the fluid twice and get teh same benefit as a tranny flush, or you can have them do it.

EDIT: They don't change the filter? This is worthless IMO. You always need to pull the pan and clean the magnet and change the filter. (Or unscrew the filter and clean the magnet on Saturns and other cars with screw on filters.)
 

J0hnny

Platinum Member
Jul 2, 2002
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Yup, tranny flush actually replaces the full volume of tranny oil. You could also do 2 drain and fills after driving around for a bit after the first drain and fill to get a little more. Flush is better though.
 

Umberger

Golden Member
Apr 13, 2005
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You get approximately the same effect by changing the fluid a few times, (with a few miles of driving in between) I like to do 3 changes, over the course of 3 days. Def. clean the magnet(s) and change the filter (i clean the magnet the first and last times, and change the filter at the same time as that third change).
 

slag

Lifer
Dec 14, 2000
10,473
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101
Tranny flushes are not good to do on high mileage transmissions.

 

Analog

Lifer
Jan 7, 2002
12,755
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Here's a quote from a tranny guy on an auto forum:

Never, ever flush a trans. There is no "safe" way to flush a trans unless you own the flush machine and control it yourself.

Flushing a trans has several pitfalls...

The most obviuos is that the last vehicle hooked up to that flushing machine probably was on it's last leg and was generating tons of debris. Most owners, when the trans starts to act up, rush to get a "flush" in the fervent hope that it will cure the problem. So....flush machines, by definition, see the worst of the worst. If the lines aren't cleaned, hooked up improperly, oil is reused or recycled, etc....then you are screwed as your trans gets the dose of debris from the last trans. No matter how good the intentions of the shop, one simple mistake and your trans gets the debris.

Flushing is supposed to negate the need for removing the pan, cleaning the debris and replacing the filter.....BS. There is considerable debris coating the inside of the trans pan with miles as anyone who has done this can attest. That is part of the maintenance, removing the pan, cleaning the screens and replacing the filter and cleaning the pan.

All that debris in the pan is laying around in areas where there is little oil flow by definition...it tends to settle in the areas where the oil is quiet and just lies there not hurting anything....until the "flush" stirs it up and circulates it thru the trans. What a concept....LOL

Reverse flush.....?????.....what logic makes anyone think that it is a good idea to reverse the oil flow path in a reverse flush and flush sediment and debris into areas that are normally protected by filters, etc...???? Stupid idea. Period. No other way to describe it.

"Transmission flush" machines are money makers for the shops and dealerships because they are quick and easy and they can actually charge more money for it under the guise of it being "better" for the trans....when it is really a detriment....suckers born every day......

Read the factory service manuals and point out the place where a transmission "flush" is recommended.

So what if all the oil cannot be removed. A "flush" doesn't remove it all either.


If you really really want to replace as much oil as possible in the trans, drain the pan, service it by removing/cleaning/changing the filter and reassemble. Refill the trans with fresh fluid. Disconnect one of the cooler lines at the radiator, put it into a bucket and start the engine. Let the trans oil pump purge the old oil into the bucket so that nothing is subjected to abnormal oil flow. Start pouring oil into the trans to keep it full while the idling engine/trans oil pump purges the fluid thru the system. Easy and quick and gets ALL the fluid out....and eliminates any risk of hooking up to a "flush machine".

Guys....FORGET THE IDEA OF FLUSHING YOUR TRANSMISSIONS. Normal trans maintenance is a good idea. Drop the bottom pan, change the filter and clean everything up and refill the trans with fresh fluid. Do the cooler line/bucket purge if you are really fastidious about changing all the fluid.....but....DO NOT hook your trans up to a flush machine.

Really now, would you get a blood transfusion from an unknown source that is reusing needles......about the same thing if you think about it. A flush will do absolutly nothing more than a good drain and refill will accomplish...and potentially a lot of harm. Do not take the risk. Just because some have had good experiences (or the lack of a bad experience) with a flush does NOT mean that they will always go good.
 

Analog

Lifer
Jan 7, 2002
12,755
3
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Originally posted by: iamwiz82
Depends on how many miles are on the tranny. Personally, I have never done it. How dirty is the filter?


No idea, my van has 198,500 miles on it.
 

iamwiz82

Lifer
Jan 10, 2001
30,772
13
81
Originally posted by: yellowfiero
Originally posted by: iamwiz82
Depends on how many miles are on the tranny. Personally, I have never done it. How dirty is the filter?


No idea, my van has 198,500 miles on it.

I'd say leave it be, either way. With that many miles you will only be causing more problems if you start to screw with things. If it works, don't touch it. :D
 

OfficeLinebacker

Senior member
Mar 2, 2005
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First off you have to choose a plae you trust not to reuse the fluid from another car. That's just preposterous.

Secondly what I do is disconnect the return line from the trans cooler in the radiator and do whatever it takes to make the old fluid drain into a bucket. Then have someone start the car and start going through the gears. Try to keep up with adding fluid through the dipstick hole, but that ain't gonna happen. You'll have to turn off the car and top off several times.

Keep doing this until the fluid coming out is clean.

Use cheap Wal-Mart fluid.

After you're done knocking all the debris loose (and hopefully into the filter), drop the pan and change the filter and clean out the pan. Once you do a few of these, you'll see that the filters rarely come close to clogging, ever. After a while you'll become comfortable with only dropping the pan every fourth flush or so. But you should always drop it on the first one to check for little metal flakes and what have you.