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Theory on flushing fluids


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I think it is well settled that flushing the brake fluid on Reattas on a regular basis in advised.

How about flushing the transmission and power steering fluids, what are the pros and cons? When I say "flush" the transmission, I am not speaking of pulling the pan and getting a few quarts out (a worthless endeavor in my opinion), I am speaking of going to a shop that has the equipment to flush 12-16 quarts of fresh fluid through the transmission so you end-up with that nice fresh pink fluid.

Or, if we did not want to spend $90.00 for a flush, could we do it ourselves with the "Volvo Procedure" such as shown here

When I speak of flushing the power steering fluid, I am thinking of a procedure such as shown here

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Yes to power steering.

<span style="font-size: 20pt"><span style="font-weight: bold"><span style="color: #CC0000">ABSOLUTELY NO!</span></span></span> to transmission power flush.

Use synthetic fluids. And the drop the pan and refill works very well, always better than a power flush. As a diy project I would purchase a 5 gallon pail of synthetic fluid from Wal-Mart and repeat the process 3 times and have a much better "flush" and better fluids.

As I recall "power flushing" circulates way too much crap from the bottom of the pan and is never recommended. To replace the filter you have to drop the pan. I had well over 200,000 miles on my Reatta with synthetic Wal-mart fluid and a transmission oil cooler.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: EDBS0</div><div class="ubbcode-body"><span style="font-size: 20pt"><span style="font-weight: bold"><span style="color: #CC0000">ABSOLUTELY NO!</span></span></span> to transmission power flush. </div></div>

How about installing a new filter, which would allow cleaning anything off the bottom of the pan, and then doing the power flush?

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This weekend I was listening to a auto advise show out of Dallas. The question was about the same thing, change the transmission fluid.

They suggested, pulling the pan and changing the filter, then refilling the transmission.......now the twist,

They suggested disconnecting the upper cooler line and attaching a hose to the line and run that to your oil change pan. Start the engine and have someone watch the amount of transmission oil going into the pan. What they seemed to be shooting for was about 5 quarts at a time. They said the average transmission takes about 16 quarts to completely fill it. Remember the torque converter is full of transmission fluid.

With their method, when you start the engine, the clean fluid is sucked into the transmission and it starts pushing the old stuff out....when it leaves the transmission, it goes to the cooler then back to the pan.

So you put in 5 quarts, and push out 5...repeat twice and you should have pushed all the old fluid out and everything is replaced. Finish by reconnecting the cooler hose and checking the fluid level

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I'm too lazy to read through the Volvo flush, but the F14 flush includes dropping the pan and replacing the filter, and wiping all you can in there. Then dumping in new fluid to replace what was in the pan (6 quarts or so). Then with the tranny cooler return line removed, start it up and pumping out a quart and dumping in a new quart at a time.

I did this at around 150k miles or so and drove another 20k...no issues. I added another cooler and used Mobil 1 ATF.

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Just DIY.

The Transaxle with a drain and refill takes 5.7L or 6.0 Quarts.

After complete overhaul 10.5L or 11 Quarts

First replacement replaces 54.5% of the fluid.

For simple math you have 1/2 old and 1/2 new fluid.

Next flush you have 3/4 new and 1/4 old and the next you have 12.5 old crap and 87.5% new.

I do like Barney's and F14s ideas HOWEVER shear off an 18 years old transmission line and you will not be a happy puppy!

I continue to like transmission coolers.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: F14CRAZY</div><div class="ubbcode-body">I'm too lazy to read through the Volvo flush, but the F14 flush includes dropping the pan and replacing the filter, and wiping all you can in there. Then dumping in new fluid to replace what was in the pan (6 quarts or so). Then with the tranny cooler return line removed, start it up and pumping out a quart and dumping in a new quart at a time. </div></div>

That is basically the Volvo procedure (filter optional) and they let 2 quarts come out or until any air bubbles can be seen in the clear line, whichever comes first. Typically start/stop the car 8-times or about 16 quarts to get a nice fresh change.

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Interesting. Our trannies don't have drain plugs, so when draining before changing the filter, the problem is to find a catchment large enough to keep the neighbors happy. Will the usual suspects accept tranny fluid for recycling? Would hate to get stuck with 16 quarts of that stuff.

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Read another way of doing this. Power flush first, drive a short time, then change filter. The theory being that when it is flushed the filter could accumulate things and why ruin a start to clog-up a new filter.

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The thing I don't like about the power flush is.....

any debris stopped by the filter is supposidly forced off and out of the transmission. This may happen but it may also just drop to the bottom of the pan.

Also since they do not remove and clean the pan, it is unlikely that backflushing will actually clean the crap off the bottom of the pan.

From the shops standpoint, it is a money maker. The mechanic hooks up the machine to the car and walks away to do something else. If it takes 15 minutes or 30 it doesn't matter because it does not require a warm body to run it once attached and turned on.

But when the mechanic must remove the pan, clean it, pull the filter and replace it, install the gasket and replace and torque the screws......then fill the transmission, we are probably talking 30 minutes to an hour.

With the machine they charge the same and it takes half the time..... also since they do not remove the pan, there is less chance of leaks.....the shops love the flushing machine.

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  • 12 years later...

Flushing (draining) engine oil is not the same issue as the transmission.

When you drain the engine oil you get almost all the old oil (you must also change the filter at the same time)

As noted above, on the transmission you only get 5-6 quarts when you drop the pan because there are many devices in the transmission that

hold fluid,  the torque converter holds the most.    So on transmissions you are pushing out the old fluid with new fluid.

That is not necessary with the engine oil.

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2 hours ago, Barney Eaton said:

Flushing (draining) engine oil is not the same issue as the transmission.

When you drain the engine oil you get almost all the old oil (you must also change the filter at the same time)

As noted above, on the transmission you only get 5-6 quarts when you drop the pan because there are many devices in the transmission that

hold fluid,  the torque converter holds the most.    So on transmissions you are pushing out the old fluid with new fluid.

That is not necessary with the engine oil.

doesn't the fluid in the torque converter stay in the torque converter?

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As noted above, on the transmission you only get 5-6 quarts when you drop the pan because there are many devices in the transmission that

hold fluid,  the torque converter holds the most. 

 

Apparently my statement was not that clear.    Different transmission require various amounts of fluid for a complete refill.

The Reatta transmission needs 22 pints (11 quarts) for a complete fill.... and 10.5 pints (5.25 quarts) if only the pan is drained.

In the case of the Reatta transmission half of the fluid in the system remains in the transmission and a lot of that is in the torque converter. 

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11 hours ago, handmedownreatta said:

doesn't the fluid in the torque converter stay in the torque converter?

 

No, not when the engine is running. Fluid stays in the converter when you take out the converter out of the transmission. It is very hard to drain out all the old fluid when it's out of the car.

 

This photo gives a good illustration of the fluid flow through the converter when the engine is running. As you can see the fluid flows through the converter and eventually out to the cooler lines. That is the reason a flush gets the old fluid out of the converter when you do a flush by connecting to the cooler lines.

 

In my opinion a combination of dropping the pan and changing the filter after a flush is probably best.  I usually just drop the pan and change the filter and fluid if the fluid still looks good and shows no signs of overheating. I'm not a fan of flushing without changing the filter.  I like to see what is building up in the pan and on the filter. That gives you a little indication of the conditions of the transmission.

 

Fluid-Circulation-e1571882129251.png

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Bottom line.........any way you choose to change the fluid is better than doing nothing.

 

Padgett's post triggered more transmission suggestions.   

If the transmission fluid is going to the radiator to be cooled (remember the radiator is somewhere near 170) how hot is the transmission fluid.

Heat kills transmissions.    For those of you in the rust belt you can skip the rest of this..... for those of us in the south,  where we may have 1/3 of the year at 90+ .... strongly consider an auxiliary transmission cooler.    Common sense will tell you that having the fluid go thru a cooler that is in ambient air,  even if it is 90F that is 80F less than the radiator.    Auxiliary coolers are easy to install on a Reatta and if you can find a Riviera with the HD cooling package, you can get the lines and cooler from the Riviera and it is a direct fit on the Reatta.

Here are some pictures that I posted elsewhere showing the many choices for coolers.... the truck section of the Pick n pull is a super place to find transmission coolers.     Also below is a chart from a trade magazine on transmission temp.

coolers.jpg

FluidChart.jpg

Edited by Barney Eaton (see edit history)
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The dealer said that the car had a 50/50 chance after a transmission flush, is this accurate or partly ignorance about Reattas and how well built they are?

 

What was the rest of the conversation?

Was the transmission having problems?

Was the "dealer" a new car dealer,  used car lot?   Was the "dealer" the owner,  did he have any mechanical expertise or just a salesman?

Reatta transmissions are more reliable than average.....based on what I hear from owners.    Reatta transmissions have been known to go 250K without repair.

Edited by Barney Eaton (see edit history)
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General Motors, I was inquiring about a transmission flush because it was sitting around for two years, and the representative said because of the vehicles age there's a chance the flush may ruin something in the transmission, making it undrivable. I was wondering if this applies to the Reatta. Nothing wrong with the transmission that I know of. 

 

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