I have been told that the only way to perform a proper transmission flush is to drop and clean the pan to get all of the clutch dust off of it. And, if you did not do this and just pour in new ATF, the new fluid would kick up the old dust on the bottom of the pan and you would not be better off. I was planning on just flushing through the cooler lines and not dropping the pan. What's the truth in this?
To drop or not to drop?
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You never know what you have until you do it I guess. I did a flush on a friends Saturn that had the trans done at the dealer before and it had a small pile of gravel and sand. I just can't fathom how they managed to make that happen with a trans service?
If you don't flush it you will only change out about a third of the fluid. For a lot of people that is fine.
If you don't flush it you will only change out about a third of the fluid. For a lot of people that is fine.
You want to read up on the car/vehicle first. In my Xterra there is no filter, only a mesh screen under the pan so I can do it both ways(drop and refill, or flush).
Normally you want to drop the pan, to take as much fluid out, then do the lines + refill. If it were me, i'd drop the pan, clean up the crud off the pan, change any filter media/gaskets to seal it up again. Before putting the pan back on empty the lines to. Seal it back up & refill.
Or, lastly, just drop the pan, etc and get it flushed. Most transmission flush places only exchange the fluid with never opening the pan.
Normally you want to drop the pan, to take as much fluid out, then do the lines + refill. If it were me, i'd drop the pan, clean up the crud off the pan, change any filter media/gaskets to seal it up again. Before putting the pan back on empty the lines to. Seal it back up & refill.
Or, lastly, just drop the pan, etc and get it flushed. Most transmission flush places only exchange the fluid with never opening the pan.
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Originally Posted By: CharlieJ
What's the truth in this?
Of course it it true that the flush would not remove cluch debris from the bottom of the pan or metalic debris from the magnets. Nor will it clean the filter for you. But it is also true that flush is easier to do and a better profit margin for a shop.
What's the truth in this?
Of course it it true that the flush would not remove cluch debris from the bottom of the pan or metalic debris from the magnets. Nor will it clean the filter for you. But it is also true that flush is easier to do and a better profit margin for a shop.
I do a pan drop & filter change the first time and never again for the life of the vehicle. I feel that all of the break-in remnants will be removed at the first pan drop.
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Easiest way to do the whole deal. Open cooler line to do flush. Run until bubbles appear. Shut off engine. Drop pan. Now it's nearly EMPTY (no mess or finesse required). Do ditty in pan/filter/magnets/etc.. Refit pan..fill with fluid. Complete flush.
Get warm fuzzy feeling of doing it all and not spilling a bunch of fluid for lack of a drain plug.
Get warm fuzzy feeling of doing it all and not spilling a bunch of fluid for lack of a drain plug.
CharlieJ, you are in luck as Mazda 3 has the drain plug, so drain and fills are easy, pan drop should be easy, as the ATF can be drained first.
One thing to note, however, is that the first time you drop the pan, you will have to scrape off the RTF gasket that was applied at factory before using the gasket that came with the ATF filter kit.
One thing to note, however, is that the first time you drop the pan, you will have to scrape off the RTF gasket that was applied at factory before using the gasket that came with the ATF filter kit.
DROP THE PAN! That is how I found out that I needed a new transmission on my 2002 Dodge Caravan. I dropped the pan and when cleaning I notice small CHUNKS!!! pin bearing pieces and etc. the vans computer was compensating and so it ran just fine I would have not known for sometime before the transmission just blew most likely somewhere on a lonely road. The transmission shop that replaced the transmission said that they have seen them like that and sooner or later it would have blown and they have seen them blow a hole in the case when they do go.
Originally Posted By: Gary Allan
Easiest way to do the whole deal. Open cooler line to do flush. Run until bubbles appear. Shut off engine. Drop pan. Now it's nearly EMPTY (no mess or finesse required). Do ditty in pan/filter/magnets/etc.. Refit pan..fill with fluid. Complete flush.
Get warm fuzzy feeling of doing it all and not spilling a bunch of fluid for lack of a drain plug.
Aren't you worried about running the ATF pump dry? Are you sure it's safe?
Easiest way to do the whole deal. Open cooler line to do flush. Run until bubbles appear. Shut off engine. Drop pan. Now it's nearly EMPTY (no mess or finesse required). Do ditty in pan/filter/magnets/etc.. Refit pan..fill with fluid. Complete flush.
Get warm fuzzy feeling of doing it all and not spilling a bunch of fluid for lack of a drain plug.
Aren't you worried about running the ATF pump dry? Are you sure it's safe?
JHZR2
Staff member
Historically the biggest driver for the ATF change was shear. Yes, dirt and junk is in there, but the filter keeps it in the pan.
I'd be sure to do it right on the manufacturer's interval, but more often fluid changes if it deviates significantly from spec viscosity. I don't buy whipping up dirt in the bottom... We don't worry about that with oil, do we ?
I'd be sure to do it right on the manufacturer's interval, but more often fluid changes if it deviates significantly from spec viscosity. I don't buy whipping up dirt in the bottom... We don't worry about that with oil, do we ?
Originally Posted By: friendly_jacek
Originally Posted By: Gary Allan
Easiest way to do the whole deal. Open cooler line to do flush. Run until bubbles appear. Shut off engine. Drop pan. Now it's nearly EMPTY (no mess or finesse required). Do ditty in pan/filter/magnets/etc.. Refit pan..fill with fluid. Complete flush.
Get warm fuzzy feeling of doing it all and not spilling a bunch of fluid for lack of a drain plug.
Aren't you worried about running the ATF pump dry? Are you sure it's safe?
It won't run completely dry, it will be OK as long as you don't let it continue running. I suck out the fluid install new filter and refill, then pump out a couple of qts at a time into a container. Then add a couple of qts new fluid and repeat.
I continue until I feel the fluid is clean or I have a few qts over trans capacity. Gary's method is quicker than sucking it out like I do. I have done it his way as well before.
If you are concerned suck it out of the pan with a vacuum pump.
Originally Posted By: Gary Allan
Easiest way to do the whole deal. Open cooler line to do flush. Run until bubbles appear. Shut off engine. Drop pan. Now it's nearly EMPTY (no mess or finesse required). Do ditty in pan/filter/magnets/etc.. Refit pan..fill with fluid. Complete flush.
Get warm fuzzy feeling of doing it all and not spilling a bunch of fluid for lack of a drain plug.
Aren't you worried about running the ATF pump dry? Are you sure it's safe?
It won't run completely dry, it will be OK as long as you don't let it continue running. I suck out the fluid install new filter and refill, then pump out a couple of qts at a time into a container. Then add a couple of qts new fluid and repeat.
I continue until I feel the fluid is clean or I have a few qts over trans capacity. Gary's method is quicker than sucking it out like I do. I have done it his way as well before.
If you are concerned suck it out of the pan with a vacuum pump.
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Originally Posted By: CharlieJ
I have been told that the only way to perform a proper transmission flush is to drop and clean the pan to get all of the clutch dust off of it.
That is the most thorough way. If I have a serviceable filter I will drop the pan and change it. If not the pan stays on until 100k and gets cleaned then.
I have been told that the only way to perform a proper transmission flush is to drop and clean the pan to get all of the clutch dust off of it.
That is the most thorough way. If I have a serviceable filter I will drop the pan and change it. If not the pan stays on until 100k and gets cleaned then.
Originally Posted By: CharlieJ
I have been told that the only way to perform a proper transmission flush is to drop and clean the pan to get all of the clutch dust off of it. And, if you did not do this and just pour in new ATF, the new fluid would kick up the old dust on the bottom of the pan and you would not be better off. I was planning on just flushing through the cooler lines and not dropping the pan. What's the truth in this?
The scum on the bottom of the pan will not be kicked up that much by the new fluid, and if it is, the filter should catch most of it. If you can remove the pan fairly easily, it is better to do it and replace the filter (if it has one). Most of the particle come when the transmission is new and all the parts/bands/clutches are wearing to match each other. After the first filter replacement and pan cleaning, you won't notice that much scum on the bottom. I just dropped the pan @67K on my truck and it was almost spotless. I had done the first pan drop @35K and it was very dirty from the break-in.
I have been told that the only way to perform a proper transmission flush is to drop and clean the pan to get all of the clutch dust off of it. And, if you did not do this and just pour in new ATF, the new fluid would kick up the old dust on the bottom of the pan and you would not be better off. I was planning on just flushing through the cooler lines and not dropping the pan. What's the truth in this?
The scum on the bottom of the pan will not be kicked up that much by the new fluid, and if it is, the filter should catch most of it. If you can remove the pan fairly easily, it is better to do it and replace the filter (if it has one). Most of the particle come when the transmission is new and all the parts/bands/clutches are wearing to match each other. After the first filter replacement and pan cleaning, you won't notice that much scum on the bottom. I just dropped the pan @67K on my truck and it was almost spotless. I had done the first pan drop @35K and it was very dirty from the break-in.
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