Transmission Cleaning

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I am slowly performing drain/fills on my gf's 98 2.2L cavalier with Maxlife ATF. She has neglected maintanence on this car (2.5 year OCI on dino, no transmission fluid change for almost 150k, never changed the coolant....) and so I decided it was time to step in and take over maintanence. I did a drain/fill this past weekend with 4qts Maxlife. The old fluid was burnt and the filter looked horrible, so changed the filter/gasket also. So now to the question....Will doing multiple drain/fills (1 drain/fill every 1k miles) until the fluid looks new also help clean out the transmission? I understand ATF does have some cleaning properties, but, I didn't want to add a product like Transtune, or the LG Trans Flush unless absolutely needed to clean up the transmission. Any input would be greatly appreciated.
 
Yes, I believe it will help. In your one drain/refill, you probably changed only ~1/3 of the transmission fluid, since the torque converter does not drain, and fluid is probably trapped elsewhere, too (?). Several more changes will increase the percentage of old fluid removed. I do not think that more than 3 changes are useful (I have done this). Also, I think that changing ATF it over time (1k miles) will allow the new fluid time to clean-up the transmission a little, and do it 'gently'. Of course, you could have the fluid exchanged with a special machine (I have had this done), which will immediately remove a high percentage of old ATF. That may or may not be worth it, factoring in your time & hassle.

I think you have already saved the engine and transmission, and you have some good plans! No need to overdo oil changes**. Instead, check the brakes, change the brake fluid, check the wipers & tires, etc. In other words, get the entire car up to a good level of maintenance first before focusing too much on oil.

** Haha -> I use Mobil 1 in 4 cars and still change it too often!
 
I'd just run one or two short intervals and then move on with my life. If there's any damage, it's already done.
 
+1 on the 3 drain and fills.
Followed by a bottle of Lubegard Red (in my opinion some of the best stuff since sliced bread)

I've done transmission services on cars much like your girlfriend's. If you wanted to do more drain and fills further apart, say every OCI for the next 2 or 3, that would work also.

You going to do anything special to clean up her engine due to the long OCI's on Dino? I'm just curious.
 
I'm guessing after 4 quarts replaced from the pan drop you now have about 50% new fluid. Sound about right? I'd leave it in there for at least a good 2-3K miles before another pan drop and filter change. With approx. 50% new fluid the cleaning process will be pretty slow (which is probably a good thing). After the 2nd pan drop and filter change, I'd run it at least another 5K miles, and then do 1 more. Should be good to go after that. Maybe keep it on a 20K to 30K mile fluid/filter change schedule from that point on. BTW I used Maxlife in my '06 Sonata and it works great. Definitely better than the OE fluid. How's it working so far in the Cavalier?
 
I recently did a bunch of drain/fills on my power steering fluid and ATF. I found this info to figure out how much new fluid I was left with after each drain/fill. I think the person who made this up was somewhat of an idiot, but...

----------------------------

Calculating dilution:

new: Percentage of new fluid you end up with after this dilution iteration
old: Percentage of new fluid you ended up with after the previous dilution iteration
cap: Capacity of whatever reservoir you are diluting the contents of
add: Volume of fluid you are removing and adding during each dilution iteration

new% = (old% * (cap - add)) + add
--------------------------
cap

For example:

Assume we're diluting power steering fluid (power steering fluid). The total system capacity ("cap") is 30 ounces. Each time power steering fluid is evacuated and replaced, the volume of power steering fluid evacuated/replaced ("add") is 10 ounces.

cap = 30 oz.
add = 10 oz.
cap - add = 30 oz. - 10 oz. = 20 oz.

new% = ((old% * 20) + 10) / 30

To start with (iteration 0), there will be 0% new power steering fluid.

0: 0%

Then, 10 oz. of power steering fluid is added (since "add" is 10 oz.), and the calculation is:

new% = ((0% * 20) + 10) / 30
new% = 0% + 10 / 30
new% = 10 / 30
new% = 33%

And after iteration 1, we have:

1: 33%

Then we add 10 oz. again:

new% = ((33% * 20) + 10) / 30
new% = 6.6% + 10 / 30
new% = 16.6 / 30
new% = 55%

And after iteration 2, we have:

2: 55%

And so on:

0: 0%
1: 33%
2: 55%
3: 70%
4: 80%
5: 87%
6: 91%
7: 94%
8: 96%
9: 97%
10: 98%
11: 99%
12: 99%
13: 99%
14: 100%
 
So now the car is shifting about the same and the oil has black specs in it due to the pint of mmo I added to the oil. I am going to change the oil/transmission fluid and filter/gasket next weekend again. This time using 3 qt's of the cheapest oil I can find and a quart of mmo. The transmission is going to get 5 qts of Maxlife this time around. Fluid is still dark brown. I'm curious to see how many changes over time it will take it to get back to reddish/pink. Also I will be doing the plugs soon so I am seafoaming it next weekend and will do the mmo piston soak when I change the plugs/wires. We'll get this car back to tip top shape!
 
I'd probably do a cooler line flush at this point. A few more drain and refills is fine as well if you don't want to flush. Some people are intimidated by doing a flush but I've done it twice (1 time each on 2 different vehicles) with nobody to help me and it worked out fine each time with no more of a mess than a pan drop.
 
I did a "flush". What a ridiculous procedure. Then again, I followed Hyundai's procedure, outlined in a TSB. It's a flush as usual except they advise letting it run with the cooling line disconnected for up to 1 minute or until the ATF stops flowing, whichever comes first. I gave it a minute. Got 5.5 quarts. I get 4.5 quarts using my Mityvac without even having to lift the vehicle. Guess which procedure makes more sense to me? But whatever. I don't argue religion.
 
Originally Posted By: glum
I did a "flush". What a ridiculous procedure. Then again, I followed Hyundai's procedure, outlined in a TSB. It's a flush as usual except they advise letting it run with the cooling line disconnected for up to 1 minute or until the ATF stops flowing, whichever comes first. I gave it a minute. Got 5.5 quarts. I get 4.5 quarts using my Mityvac without even having to lift the vehicle. Guess which procedure makes more sense to me? But whatever. I don't argue religion.


If you added some new fluid to the pan through the dipstick (assuming the fluid is pulled from the pan and moved through the TC and radiator) you could have got nearly all the rest of the old fluid out. IIRC the fluid comes out of the pan by the pump. Once the pan is dry you don't have the fluid pressure to push any more fluid out. The pump isn't going to pump the full capacity out.

Of course, it you are using a mightyvac and do a drain and refill at faster the 30,000 mile intervals you'll be fine too. I would think once a year or 15-20,000 miles would be satisfactory too. The mightyvac probably doens't take more than 10 minutes to drain and refill eiher.

Assuming a 50% exchange rate
1 fill 50% old fluid
2 25% old
3 12.5%
 
^ If I added new fluid while performing the flush, what would have happened is that I would have been diluting the old fluid with the new fluid, the same as when performing multiple drain/fills or evacuation/fills.

Now that I've done a "flush" and several evac/fills, I've settled on doing a evac/fill every 10K miles.

So my answer to the OP is that yeah, do a few drain/fills and you'll be set. Here is how I figure out how much new fluid I have:

Calculating dilution:

new: Percentage of new fluid you end up with after this dilution iteration
old: Percentage of new fluid you ended up with after the previous dilution iteration
cap: Capacity of whatever reservoir you are diluting the contents of
add: Volume of fluid you are removing and adding during each dilution iteration

new% = (old% * (cap - add)) + add
--------------------------
cap

For example:

Assume we're diluting power steering fluid (PSF). The total system capacity ("cap") is 30 ounces. Each time PSF is evacuated and replaced, the volume of PSF evacuated/replaced ("add") is 10 ounces.

cap = 30 oz.
add = 10 oz.
cap - add = 30 oz. - 10 oz. = 20 oz.

new% = ((old% * 20) + 10) / 30

To start with (iteration 0), there will be 0% new PSF.

0: 0%

Then, 10 oz. of PSF is added (since "add" is 10 oz.), and the calculation is:

new% = ((0% * 20) + 10) / 30
new% = 0% + 10 / 30
new% = 10 / 30
new% = 33%

And after iteration 1, we have:

1: 33%

Then we add 10 oz. again:

new% = ((33% * 20) + 10) / 30
new% = 6.6% + 10 / 30
new% = 16.6 / 30
new% = 55%

And after iteration 2, we have:

2: 55%

And so on:

0: 0%
1: 33%
2: 55%
3: 70%
4: 80%
5: 87%
6: 91%
7: 94%
8: 96%
9: 97%
10: 98%
11: 99%
12: 99%
13: 99%
14: 100%
 
So I did a other drain/fill and added a bottle of lubegard red. The transmission now has a rough downshift from second to first gear. This was happening before I put the lubegard in there. I used 4 qts of supertech dexron iii and am wondering if this rough downshift has to do with the new fluid cleaning out some of the garbage in there or if there is maybe a pressure change from changing out the old fluid that could be causing this. Oh and I changed the filter and gasket again. Any ideas?
 
^ If I added new fluid while performing the flush, what would have happened is that I would have been diluting the old fluid with the new fluid, the same as when performing multiple drain/fills or evacuation/fills.

I do not think that this is correct in regards to a flush.

Before the flush you drain the trans pan and install new fluid.
Then begin the flush procedure - a few quarts at a time.
Since you disconnect the return hose - old transmission fluid will not contaminate your new fluid - you are draining old fluid and replacing it with 100% new.
It is not like a drain and refill at all. Drain and refills are great if the trans has been properly maintained all of its life - in the OP position a flush would have been easier on his wallet and better for the trans - although I am sure some would argue this.

For the OP a flush - and a Magnefine would have been perfect. But to each is own>:)
 
I did a "flush". What a ridiculous procedure. Then again, I followed Hyundai's procedure, outlined in a TSB. It's a flush as usual except they advise letting it run with the cooling line disconnected for up to 1 minute or until the ATF stops flowing-

I would never perform a flush this way - what is Hyundai thinking?

Introducing air into a hydraulic system and running it dry ?

- I would replace the fluid as it is coming out of the system - I drain 2 quarts - stop the engine and replace 2 quarts - then repeat until you reach your desired ATF quantity.
 
^The only way it would work is if the pump no longer sends fluid to be cooled because of being low on fluid. The vehicle isn't actually driven or shifted through gears while low on fluid, that in of itself wouldn't hurt the car. The return line sending only what the pump is capable of without new fluid added while doing this wouldn't in of itself allow air into the system.

If you feel safer, just add some new ATF at a 'slightly' less rate while the old ATF is pumped out. No harm if the car is just in park. The torque convertor may/may not let it's fluid out depending on the car/transmission etc.
 
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