transmission flush

[bigdman]

is it possible when changing the transmission fluid to somehow "flush it" by using the cooler lines? i had a thought about this but i don't want to try it unless i know it is safe.

[DaveFromColorado]

I used a vacuum pump once to pull everything out of the converter - it didn't work real well, but it got some of the extra crud out.

 

One thing you can get is a drain kit for your pan, where you basically drill a hole in the pan, and install a drain plug ... that way you can change your trans fluid a bit easier.

 

--Dave.

[CowboyBilly9Mile]

Funny that someone brought this one up as I'm going to be flushing mine sometime in the next couple of months. Here's my gameplan:

 

1) Drive vehicle ~ 15 miles to fully warm up tranny.

2) Drop the tranny pan, clean it, and replace the filter and pan gasket. Check bolt torque on valve body while filter is off. There will never be a more convenient time.

3) Refill tranny with new fluid, exactly the same amount that was drained.

4) On lower side of the tranny cooler on the radiator, install a hose to either the radiator or the steel tranny line (I don't know which one is pressurized yet; I will when the time comes). Place the other end of the hose (pressurized)in a five gallon bucket. Secure this hose; I'd expect it will want to whip around. A helper might be useful for this.

5) Consider capping the return line to the tranny.

6) You will need to know in advance what the total tranny fluid capacity is. Have the tranny fluid ready to add during the flush (bottles open in advance). Insert tranny fluid funnel into trany dipstick tube.

 

**Note that the engine has NOT been started since the end of step one.

 

7) Have a helper start the car and watch the fluid being sent into the bucket. Try to estimate the rate that it's being pumped there. I'm guessing about one quart every 15 seconds; I/you will have to make the determination when the time comes or hopefully be able to determine it from a GM service manual.

8 ) Add fluid to the tranny via the funnel. If it's pumping out one quart every 15 seconds, then add a quart at each 15 second interval. Continue doing this until the total tranny fluid capacity has been sent through the tranny. I personally plan to run two extra quarts through.

9) Have helper stop car.

10) Reconnect tranny cooler line. Verify correct fluid level and leak free condition.

 

*In step four, if the steel line is pressurized, then reconnect it to the cooler (radiator) and connect a hose to the cooler discharge at the top of the radiator. The idea here is to flush the cooler.

[DaveFromColorado]

last time I saw that flush method being done, the guy evacuated his converter and smoked the stater.

 

--Dave.

[CowboyBilly9Mile]

The important thing to remember here will be to NEVER let the tranny run W/O fluid available in the pan. By doing this, the tranny will have no clue that it's being flushed and in fact, the tranny will be operating no differently than if the vehicle were simply sitting there running.

 

*I have heard of *problems* when people run the tranny dry during a flush. Sleeping at the wheel comes with a price .

[DaveFromColorado]

well, I wish ya the best of luck with that, and hope nothin' goes wrong.

 

--Dave.

[Supreme Cutlass]

Funny that someone brought this one up as I'm going to be flushing mine sometime in the next couple of months. Here's my gameplan:

 

1) Drive vehicle ~ 15 miles to fully warm up tranny.

2) Drop the tranny pan, clean it, and replace the filter and pan gasket. Check bolt torque on valve body while filter is off. There will never be a more convenient time.

3) Refill tranny with new fluid, exactly the same amount that was drained.

4) On lower side of the tranny cooler on the radiator, install a hose to either the radiator or the steel tranny line (I don't know which one is pressurized yet; I will when the time comes). Place the other end of the hose (pressurized)in a five gallon bucket. Secure this hose; I'd expect it will want to whip around. A helper might be useful for this.

5) Consider capping the return line to the tranny.

6) You will need to know in advance what the total tranny fluid capacity is. Have the tranny fluid ready to add during the flush (bottles open in advance). Insert tranny fluid funnel into trany dipstick tube.

 

**Note that the engine has NOT been started since the end of step one.

 

7) Have a helper start the car and watch the fluid being sent into the bucket. Try to estimate the rate that it's being pumped there. I'm guessing about one quart every 15 seconds; I/you will have to make the determination when the time comes or hopefully be able to determine it from a GM service manual.

8 ) Add fluid to the tranny via the funnel. If it's pumping out one quart every 15 seconds, then add a quart at each 15 second interval. Continue doing this until the total tranny fluid capacity has been sent through the tranny. I personally plan to run two extra quarts through.

9) Have helper stop car.

10) Reconnect tranny cooler line. Verify correct fluid level and leak free condition.

 

*In step four, if the steel line is pressurized, then reconnect it to the cooler (radiator) and connect a hose to the cooler discharge at the top of the radiator. The idea here is to flush the cooler.

 

Not worth the risk

[DaveFromColorado]

I wish I could remember the hydraulic circuit on that, but IIRC the converter pumps into the cooler ... but I can't remember where the fluid goes after the cooler - it's been a while.

 

--Dave.

[Pontiac6KSTEAWD]

I would not do that method mentioned. The tranny utilizes the transmission fluid pressure comeing back to the tranny after being cool. it processes thru the tranny, makes its way to the pan, and then repeats the process. Maintaining the pressure is the priority on this. I know you guys hate the instant oil change places, but if you have a valvoline instant oil change near you. I would recomend there trans flush service. It uses a cylinder filled on one end with new fluid, and has a o-ring moving cylinder in the top of the new fluid. It connects to the line coming out of the radiator, and uses the transmissions own pump to move the cylindrical cylinder down, and move the new fluid, under the transmissions own pressure, into the tranny. Its a very good system, and recovers about 90%+ of the old fluid while never having run the tranny dry for one second. It works, I have performed it on all my cars (both when I worked then, and after leaving them).

[Schurkey]

I have done the cooler-tube flush on my '92 Euro 3.4. And on lots of other cars and light trucks. No problem whatsoever.

 

It won't be a scientific as it has been made out to be. You watch the color of the fluid coming out the cooler tube--when it looks fresh and clean you're done, shut the car off. Until then, you'll be dumping in fluid like mad. I overfill the pan deliberately right after the filter change, gives a couple of quart "cushion" so you don't run the pan dry. Of course, you will adjust the fluid level once you're done flushing the system. If it's low, add more. If it's over full, run some more out the cooler tube. Easy. Simple.

 

[Edit: Keep in mind that the fluid will be cool, so don't over-fill. And you can just about count on having to add more. It's tough to get the fluid into the trans fast enough. Keep your quarts of fluid HANDY and ALREADY OPENED. Pour the quarts into CLEAN gallon jugs before hand so you can pour faster, if you have some CLEAN gallon jugs available. Just getting the fluid down the funnel 'n' fill tube fast enough is...interesting.]

 

The fluid returned to the trans by the cooler tube is used to lube the gear train. Since the car is in Park and not moving...what in the gear train is moving and therefore needs to be lubed?

 

Given a choice, I'll dump the fluid AFTER it goes through the trans cooler. So I use a "special tool", a length of tubing and a tube nut the appropriate size to thread into the radiator, or to patch into an external cooler. Use that to route the "old" fluid into the drain pan. That way, you remove all the old fluid from the cooler(s) as well.

[DaveFromColorado]

The fluid returned to the trans by the cooler tube is used to lube the gear train. Since the car is in Park and not moving...what in the gear train is moving and therefore needs to be lubed?

 

in ANY transmission, automatic, and manual, all the gears are turning while the engine is running (this includes the chain which needs to be lubed too ya know) and until one of the parts is stopped VIA the clutching system inside the transmission, or engaged with a fork using some type of coupling system.

 

so even when you're in park, and no moving, the only part not moving is the output shaft/differential. This means the bearings between the output shaft and inputshaft are gettin' the spin of their lives and without lube, it decrease the life, not to mention the hell that chain is going through spinning at 600 - 1000 RPM's ...

 

--Dave.

[Schurkey]

in ANY transmission, automatic, and manual, all the gears are turning while the engine is running (this includes the chain which needs to be lubed too ya know) and until one of the parts is stopped VIA the clutching system inside the transmission, or engaged with a fork using some type of coupling system.

 

so even when you're in park, and no moving, the only part not moving is the output shaft/differential. This means the bearings between the output shaft and inputshaft are gettin' the spin of their lives and without lube, it decrease the life, not to mention the hell that chain is going through spinning at 600 - 1000 RPM's ...

 

--Dave.

 

EDITED because I'm re-thinking the whole deal. Yup, you may be right.

[CowboyBilly9Mile]

It is true that after the fluid leaves the cooler it does in fact get directed back into the tranny to lube the gears. I'll be happy to make the diagram showing fluid flow through the tranny available if anyone is interested; the diagram I'm talking about is shown in the dealer service manual. However, considering how there is no load on the components and there is already a film of oil on the moving parts, there's little reason to be concerned during the couple of minutes of operation during the flush. I've done the flush as described on my nearly new pickup with full confidence and as expected, no problems. Just keep up on adding tranny fluid while the engine is running and add new fluid at the same rate as the old is expelled. I would add that if anyone is deeply concerned with flushing using the noted method that they do take it to a quickie lube for piece of mind. Just make sure they use the correct fluid .

 

*The chain used in these trannies sort of reminds me of a machine I designed for a major snack food processor back in 1996 (I'm a ME). I used a medium duty single chain lubed with 30 wt oil to drive a 3,000lb conveyor cart that reversed direction virtually instantly and several times a minute over an average running cycle of 10 hours/day. That machine, nearly 10 years later, hasn't let the customer down once .

[bigdman]

thanks for all the input, glad i can hear some other opinions before i try it without knowing what will happen. this is what i was thinking of doing, filling a bucket with about 7-8 quarts of new fluid, putting the return line in the bucket of new fluid, and putting the other line in the empty bucket and just running it till clear fluid came out. would this work?

[DaveFromColorado]

no.

 

The trans uses pressure to move the fluid through the cooler, meaning there's no suction to pull the new fluid into the trans.

 

You'd be better off going to one of those quick-lube (Jiffy Lube, Instant Oil Change, or just about any other shop for that matter) and having them do it, not only will that flush your trans fluid, it will also put the flush under a warranty so if the trans does blow up because of it, they're fixing it for you.

 

--Dave.

[Crazy K]

The trans uses pressure to move the fluid through the cooler, meaning there's no suction to pull the new fluid into the trans.

 

correct. Our cars don't suck

[ycartf]

So if I understand correctly, the Jiffy Lube or whatever has some system that pipes into the return (under pressure) to the transmission and uses the pressurized "old" fluid to push a cylinder of new fluid in? I am a paramedic/firefighter by trade and am trying to think up some way to insert some IV/O2 tubing(with possible syringe) into there and use the same concept.

[Pontiac6KSTEAWD]

The diference is, the design that those shops use, holds anywhere from 2-12 gallons, which is why it has the ability to completely flush the entire system. The one VIOC (valvoline instant oil) holds about 4-5 gallons, depending if the tech fills it up all the way.,.

[DaveFromColorado]

well, most of them only hold 18 Qts, which often is enough to flush the transmission.

 

The best machine I've seen for this type of service is the T-Tech brand machines ...

 

http://www.sjdiscounttools.com/ttctt400.html

 

or

 

http://www.sjdiscounttools.com/ttctt500.html

 

- both hold 18 Qts, are easy to use, blah, blah, blah -

 

Anyhow, before I go to get my trani's flushed, I usually drop the pan, change the filter and gasket, and top it off with fresh (super inexpensive) fluid - that way you'll get more of the particles out of your transmission, and you'll end up with a cleaner, happier transmission.

 

--Dave.

[Pontiac6KSTEAWD]

Thats the machine that VIOC uses, unless they have changed within the last couple months..

 

18 qts = 4 1/2 gallons..

[DaveFromColorado]

that's the easiest to use machine too ... any idiot can use it.

 

--Dave.