Transmission maintenance

[Kaspian]

What is the difference between the two?

 

[SilthDraeth]

Draining: They remove the drain plug from your transmission, let it drain out, somewhat similar to draining your oil. Then they refill it with the same amount they drained.

Flushing, they hook a pump up to where your dipstick is, and they pump fresh fluid through the system, forcing all the other fluid out that typically would not be removed during just a drain and fill.

 

[CrackRabbit]

There are a couple of variations to what SilthDraeth posted.

First quite a few cars don't have drain plugs for the transmission, the pan must be removed to drain it. Either way it is done it only removes 1/2 to 2/3 of the transmission fluid. The rest is stuck in the valve bodies and the torque converter.

A flush can also be done by hooking a machine to a the lines going to and from the transmission cooler and pumping fresh fluid through the transmission, this replaces almost all of the old fluid, but can knock deposits loose within the transmission and cause further problems.

 

[Kaspian]

Originally posted by: CrackRabbit

A flush can also be done by hooking a machine to a the lines going to and from the transmission cooler and pumping fresh fluid through the transmission, this replaces almost all of the old fluid, but can knock deposits loose within the transmission and cause further problems.

So, forgive my ignorance if my following theory is wrong: It would be advisable to have a "drain & refill" and not a "flush" on a transmision with alot of miles on it, and that such transmision has never had either of both maintenance methods. I'm just thinking that if the trans has never had one done (either or) more than likely there would be some deposit build up in there............................................................................?


ps: Lets not forget I'm no mechanic

 

[Bartman39]

With alot of miles and little or no maintenance it would alot safer to just do the drop pan and change filter add fluid rather than a flush... Most normal wear of the clutch & steels material will collect in the pan and most pans have magnets that also help with this...

A flush will disturb what ever residue that has collected in the pan and valve body and possibly get into places that might cause the trans to fail or become erratic in its operation...

Flushing should be done very reg like around 20K-40K miles and a filter change around 50K intervals... In addition flushing is like transfusion for your tranny and gives it new blood to live on, but it can do more harm than good in an older transmission.. Also when doing a filter change you do add a few quarts of new fluid which also replenishes the additives that the transmission needs...

 

[drpootums]

you could also drop the pan and change the fluid and filter, then drive for a week or so then change fluid again. It might cost more, but chances are you'll get between 70-90% of the fluid changed, without the risk of damaging your transmission.

 

[BUTCH1]

Originally posted by: drpootums
you could also drop the pan and change the fluid and filter, then drive for a week or so then change fluid again. It might cost more, but chances are you'll get between 70-90% of the fluid changed, without the risk of damaging your transmission.

I used to do a "cheater" change on my old escort, remove dipstick and use clean aquarium
tubing to siphon out old fluid then replace with fresh. Eventually though, you will need to
have the pan dropped to change the filter. Still it's an easy way to refresh the fluid, traded
the car in @170K, never a transmission problem..

 

[Pacfanweb]

The best way is the flush. Drain and refill only gets a few quarts of fluid out...most is in the torque converter. Some cars have a drain plug on the converter, too, but not many.

People always use that old "don't flush it if it has lots of miles and has never been changed", but I've seen thousands done and never seen one come back with a bad tranny because of flushing. I'd flush it no matter how many miles it has, personally. Again, I've seen it done many, many times on high-mileage cars that had never been serviced before with no ill repercussions.

The flush, if done right, gets the trans so clean that there's really not much gunk left inside. I've never seen a machine that flushes the way Silth describes, but based on that description, the other way is much better. And almost no cars have drain plugs on auto transmissions, anyway.
The machines we used (BG) flush through the trans cooler lines.

You first put the cleaner in and let it run awhile to loosen stuff up and basically just circulate through the trans.
Then you have the machine start putting fluid in one line, while the old fluid is being pumped out the other. You have a sight tube on the side where the fluid is being discharged that lets you see when you have perfectly clean fluid coming out...then you're done.

When we first got the machines, the BG guy demo'd it for us. We took an old Aerostar that was in for tranny failure...high miles and it wouldn't pull at all. Fluid was SMOKED...totally black. So we were already going to overhaul it.
He did the flush on it, then the tranny man removed it and tore it down. It was practically spotless inside. All the tranny guys said "this'll be great for customers, but it's going to cost us a lot of work". Very impressive, the way it works.

 

[IGBT]

..there's lots of diffrent trans fluid requirements. use the wrong juice and you'll kill the box. something to do wit friction reducers and band material.

 

[Sniper82]

nvm

 

[MrPickins]

Originally posted by: drpootums
you could also drop the pan and change the fluid and filter, then drive for a week or so then change fluid again. It might cost more, but chances are you'll get between 70-90% of the fluid changed, without the risk of damaging your transmission.

This is what I'm going to do.

I've changed the filter and what fluid I could, overfilled it to the Full Hot region (while cold), then drained the excess.

Next weekend I plan on draining it again and repeating the process. I figure I'll have 80-90% clean fluid.

 

[SarcasticDwarf]

Originally posted by: Pacfanweb
People always use that old "don't flush it if it has lots of miles and has never been changed", but I've seen thousands done and never seen one come back with a bad tranny because of flushing. I'd flush it no matter how many miles it has, personally. Again, I've seen it done many, many times on high-mileage cars that had never been serviced before with no ill repercussions.

It won't necessarily cause the transmission to blow, but it can lead to problems:

Case 1: 1989 Mustang (in 2001) - Immediately after a transmission flush the radiator started leaking

Case 2: 1998 Ram (in 2007) - 1k miles after a flush the transmission blew after a pump inside exploded which blew the rest of the tranny. (could be unrelated, I have no way of knowing)

 

[BUTCH1]

Originally posted by: SarcasticDwarf

Originally posted by: Pacfanweb
People always use that old "don't flush it if it has lots of miles and has never been changed", but I've seen thousands done and never seen one come back with a bad tranny because of flushing. I'd flush it no matter how many miles it has, personally. Again, I've seen it done many, many times on high-mileage cars that had never been serviced before with no ill repercussions.

It won't necessarily cause the transmission to blow, but it can lead to problems:

Case 1: 1989 Mustang (in 2001) - Immediately after a transmission flush the radiator started leaking

Case 2: 1998 Ram (in 2007) - 1k miles after a flush the transmission blew after a pump inside exploded which blew the rest of the tranny. (could be unrelated, I have no way of knowing)

The radiator leaking might have been due to a clumsy mechanic who damaged it when
removing the lines. The tranny fluid is circulated through the rad. tank to help cool it,
that's about it..

 

[Pacfanweb]

Originally posted by: SarcasticDwarf

Originally posted by: Pacfanweb
People always use that old "don't flush it if it has lots of miles and has never been changed", but I've seen thousands done and never seen one come back with a bad tranny because of flushing. I'd flush it no matter how many miles it has, personally. Again, I've seen it done many, many times on high-mileage cars that had never been serviced before with no ill repercussions.

It won't necessarily cause the transmission to blow, but it can lead to problems:

Case 1: 1989 Mustang (in 2001) - Immediately after a transmission flush the radiator started leaking

Case 2: 1998 Ram (in 2007) - 1k miles after a flush the transmission blew after a pump inside exploded which blew the rest of the tranny. (could be unrelated, I have no way of knowing)

Case 1: Probably was bad to start with, and the mechanic messing with the fitting on the radiator made it leak. Or, the tech simply screwed it up.

Case 2: No way to tell if it was related or not. Dodges have such bad tranny problems (and really did back then) that I'm surprised it lasted that long before needing an overhaul.
But I doubt flushing it made the pump go bad, and regardless.....I'm sure people can come up with a few stories like this but they will be the exception, not the rule.
Again, I've seen literally thousands of these things done and it always helps more than it hurts.

 

[steppinthrax]

There is actually a poor man's transmission flush method that involves 2 buckets and some tubing. You connect the tubbing inline with the transmission cooler lines and fill one bucket with new fluid putting one hose in each. I don't believe this can cause any damage to your system because some of the transmission flush devices that I've seen actually use the tranmssion pump as the flusher.

But if you were to change the tranmssion fluid then go back and drain it again after a week or so you would get rid of most of the bad fluid.

 

[SilthDraeth]

Originally posted by: Kaspian

Originally posted by: CrackRabbit

A flush can also be done by hooking a machine to a the lines going to and from the transmission cooler and pumping fresh fluid through the transmission, this replaces almost all of the old fluid, but can knock deposits loose within the transmission and cause further problems.

So, forgive my ignorance if my following theory is wrong: It would be advisable to have a "drain & refill" and not a "flush" on a transmision with alot of miles on it, and that such transmision has never had either of both maintenance methods. I'm just thinking that if the trans has never had one done (either or) more than likely there would be some deposit build up in there............................................................................?


ps: Lets not forget I'm no mechanic

Depends on if you have the money to fix your transmission. A full flush can "break" a transmission that is already going bad. If you have the cash, and can afford a transmission rebuild, then go with the full flush. And if it has problems, then get the transmission fixed.

If you just need the car to last another year, and the transmission is working fine, just drain and fill.

Thats my opinion.

 

[prontospyder]

I try to drain and fill the tranny fluid every 10,000 miles. Nissan made it easy by adding a drain plug for the transmission.

 

[Thegonagle]

Originally posted by: Kaspian

Originally posted by: CrackRabbit

A flush can also be done by hooking a machine to a the lines going to and from the transmission cooler and pumping fresh fluid through the transmission, this replaces almost all of the old fluid, but can knock deposits loose within the transmission and cause further problems.

So, forgive my ignorance if my following theory is wrong: It would be advisable to have a "drain & refill" and not a "flush" on a transmision with alot of miles on it, and that such transmision has never had either of both maintenance methods. I'm just thinking that if the trans has never had one done (either or) more than likely there would be some deposit build up in there............................................................................?


ps: Lets not forget I'm no mechanic

It would be advisable to do a drain and refill a few times in a row a couple hundred to a couple thousand miles apart.

The new fluid will really clean stuff up because the detergents/additives--which stopped working long ago in the old fluid--get replaced. The sludge that gets dissolved by the new fluid will "use up" the new detergents pretty quickly as a result. Therefore, you will want to replace it a few times in a row before resuming the normal maintenance schedule.

That's what I do whenever I get a "new" old car with an automatic transmission, and I've never had any problems. (And I've owned a lot of cars!)

However, if you're changing fluid because the transmission is starting to have problems, it's already too late. (I think this could be where the myth that it's bad to change the fluid in an old transmission that's never had it done may have started--by the time the the fluid was changed, the transmission was about to blow up anyway.)

 

[Kaspian]

Originally posted by: Thegonagle

However, if you're changing fluid because the transmission is starting to have problems, it's already too late. (I think this could be where the myth that it's bad to change the fluid in an old transmission that's never had it done may have started--by the time the the fluid was changed, the transmission was about to blow up anyway.)

Oh, no. My wife's '03 Elantra is reaching 130-140k (somewhere in there)miles. The car is running just fine. But I'm starting to beleive its time for some maintenance on the car

 

[Kaspian]

Originally posted by: prontospyder
Nissan made it easy by adding a drain plug for the transmission.

Is that rare? For a car's trans not to have a drain plug? Just curious.

 

[prontospyder]

Originally posted by: Kaspian

Originally posted by: prontospyder
Nissan made it easy by adding a drain plug for the transmission.

Is that rare? For a car's trans not to have a drain plug? Just curious.

Not sure what the ratio of cars w/drain plugs vs cars without is but the Dodge Spirit, Intrepid, Chrysler Voyager we owned didn't have tranny drain plugs.

 

[Pacfanweb]

Originally posted by: Kaspian

Originally posted by: prontospyder
Nissan made it easy by adding a drain plug for the transmission.

Is that rare? For a car's trans not to have a drain plug? Just curious.

Yes, it's rare for an automatic transmission to have a drain plug.

 

[Eos]

1996 Toyota Avalon
4 speed auto
145k miles

I have no drain plug and no filter.
87K miles in 7.5 years and I've had it flushed 4 times, last week was number 4.

I think this new repair place I found uses the sight tube system mentioned above. They mentioned it when I was asking about the procedure.