Maximizing ATF Extraction via Topsider - PeachParts Mercedes-Benz Forum

shertex · #1 01-02-2012, 11:59 AM

Between filter changes, I remove and replace ATF using a topsider. By doing this several times, I wind up with about 80% new fluid. When I do this with transmission at operating temp on level ground, I get out about 2.3 quarts.

If the car were pointing downward, would I get slightly more? I just don't have a sense as to where the dipstick tube hits with respect to the fluid. Car is a 91 300D.

sixto · #2 01-02-2012, 02:23 PM

In this picture, the dipstick tube is the black tube descending from the forward passenger side ending at the bracket. As such I'd raise the front driver side of the car to maximize extraction.

The problem is knowing where the extractor tip is in the sump. If you push in too much hose it might curl around the aft end and head for a higher section of the sump. Maybe someone can tell you where the dipstick ends in the tube for reference. Or withdraw the extractor slowly when you hear the gurgling sound.

BTW, I do the same with power steering fluid.

Sixto
87 300D

tangofox007 · #3 01-02-2012, 04:11 PM

Quote:

Originally Posted by shertex

I just don't have a sense as to where the dipstick tube hits with respect to the fluid.

Front, right corner. Elevating the left side of the car would be your best bet.

vstech · #4 01-02-2012, 10:08 PM

so... you don't wanna drain the TC?

Stretch · #5 01-03-2012, 03:30 AM

Quote:

Originally Posted by vstech

so... you don't wanna drain the TC?

Yep that must hold quite a bit - what is it about 2 litres?

sixto · #6 01-03-2012, 02:04 AM

Probably doesn't want to pull the belly pans.

Sixto
87 300D

sixto · #7 01-03-2012, 02:09 PM

There's a philosophical question of whether the fluid is 80% clean or 20% dirty. As a counterpoint, would you rather have 4 tires with 75% treadlife remaining, or 3 new tires and one down to the cords? Does anyone know how new ATF mixes with old ATF? It's disconcerting enough that a by-the-book ATF replacement replaces only about 90% of the fluid. Besides, the TC drain is right there when you get around to changing the filter.

Sixto
87 300D

Stretch · #8 01-03-2012, 02:14 PM

Quote:

Originally Posted by sixto

There's a philosophical question of whether the fluid is 80% clean or 20% dirty. As a counterpoint, would you rather have 4 tires with 75% treadlife remaining, or 3 new tires and one down to the cords? Does anyone know how new ATF mixes with old ATF? It's disconcerting enough that a by-the-book ATF replacement replaces only about 90% of the fluid. Besides, the TC drain is right there when you get around to changing the filter.

Sixto
87 300D

Indeed - if you ever take the whole transmission to bits I'm sure like me you'll be amazed at how much of the sodding stuff still bleeds out all over your work surface, the garage floor, the bags, the boxes, your clothing, your shoes...

shertex · #9 01-03-2012, 02:30 PM

Quote:

Originally Posted by sixto

There's a philosophical question of whether the fluid is 80% clean or 20% dirty. As a counterpoint, would you rather have 4 tires with 75% treadlife remaining, or 3 new tires and one down to the cords? Does anyone know how new ATF mixes with old ATF? It's disconcerting enough that a by-the-book ATF replacement replaces only about 90% of the fluid. Besides, the TC drain is right there when you get around to changing the filter.

Sixto
87 300D

Of course, I can get the fluild to any degree of purity I want based on the number of extractions.

Do you really find it disconcerting to have 90% pure fluid? Do you feel the same about your oil?

EDBSO · #10 01-03-2012, 09:40 PM

Quote:

Originally Posted by sixto

There's a philosophical question of whether the fluid is 80% clean or 20% dirty. As a counterpoint, would you rather have 4 tires with 75% treadlife remaining, or 3 new tires and one down to the cords? Does anyone know how new ATF mixes with old ATF? It's disconcerting enough that a by-the-book ATF replacement replaces only about 90% of the fluid. Besides, the TC drain is right there when you get around to changing the filter.

Sixto
87 300D

Brother-in-law manages a transmission shop and he says by doing a partial flush you are renewing the additive package and that it is very beneficial. 100% replacement is not necessary.

Also knew a commercial fleet manager who every couple of years would take the lower rad hose off and then top up the rad with fresh fluid to renew the additive package and he never had any problems with his fleet of rads.

Me I drain my converter and drop the pan every couple of years, easy and reasonably inexpensive and I feel better about it all. I do the same partial drain and fills on the rad.

Thought that I should mention that I regularly "refresh" the power steering fluid with partial flushes, just to keep the additive package fresh.

Now the "blinker fluid", I am still on the old factory fill as I believe it is a lifetime fluid?

sixto · #11 01-03-2012, 02:49 PM

There are things in life that bother me more

I'm not questioning your method because I think it's wrong, I just don't understand the benefit. I think the key is determining the transition point between improving old ATF by adding new and pouring good ATF into bad. If you don't extend the filter interval, it seems overly cautions, not that that's a bad thing. If you extend the filter interval, how do you figure how long to go?

I'm spoiled by the TC drain. Our Mopar or Bowtie don't have a drain so I do the bit of flushing through the tranny cooler with the engine running after replacing the filter.

Sixto
87 300D

shertex · #12 01-03-2012, 03:13 PM

Quote:

Originally Posted by sixto

There are things in life that bother me more

I'm not questioning your method because I think it's wrong, I just don't understand the benefit. I think the key is determining the transition point between improving old ATF by adding new and pouring good ATF into bad. If you don't extend the filter interval, it seems overly cautions, not that that's a bad thing. If you extend the filter interval, how do you figure how long to go?

I'm spoiled by the TC drain. Our Mopar or Bowtie don't have a drain so I do the bit of flushing through the tranny cooler with the engine running after replacing the filter.

Sixto
87 300D

In part due to the mess/hassle, and in part due to various threads I've read from people having difficulty changing the filter and gasket (torquing problems, leaking, etc.) as well as dealing with the torque converter, I've never done it myself...my indie does it. But I suppose I could be persuaded to take the plunge.

For now, the routine that I've settled on is to change the fluid using multiple extractions every 25,000 miles, then every third time (i.e. once every 75,000 miles) have the filter and gasket changed. While this certainly isn't by the book, it saves me a little money (and/or effort). I don't considered a breach in the filter to be likely and, if the filter were starting to get clogged, I figure I'd probably notice it.

I freely admit that I may be being penny wise and pound foolish....

Stretch · #13 01-03-2012, 03:06 PM

I think the thing that is a bit misleading is...

...the filter in the transmission.

It isn't like the filter in your engine - OK on the side of the engine. Oil in a transmission doesn't get pumped from the sump through the filter and then into the moving parts. The filter in the transmission is only there to protect the valve body. There isn't much flow through a filter fitted under the valve body.

I think the best way of getting junk out of the transmission is to change the oil and the filter - the best thing about changing the filter is that you have to remove the sump pan and then you have the opportunity to remove all of those glittery bits of junk (that hopefully won't be there)...

shertex · #14 01-03-2012, 03:17 PM

Quote:

Originally Posted by Army

I think the thing that is a bit misleading is...

...the filter in the transmission.

It isn't like the filter in your engine - OK on the side of the engine. Oil in a transmission doesn't get pumped from the sump through the filter and then into the moving parts. The filter in the transmission is only there to protect the valve body. There isn't much flow through a filter fitted under the valve body.

This comment helps confirm me in my unorthodox practice.

BTW next time I DO get the filter changed, I'm going to rip it open to see what it looks like.

Stretch · #15 01-03-2012, 03:40 PM

My feeling is that if you want to be cheap and not change the filter - well it is your car - your choice. However I think you are missing the point a bit about the process of changing the filter.

The process of draining through the lowest point - carrying heavier crud with it is important. Sucking oil out of the top of the transmission might leave heavier elements in the transmission. Not wiping out the lowest point in the transmission might also leave crud behind.

As I said the filter only protects the valve body. Have you seen the price of replacement brake bands for a 722.3?

Please don't misunderstand me - I'm not preaching - I'm just playing the FSM's advocate!