How good is a Trans flush thru the dipstick?

[Donald]

Originally Posted By: JTK
Originally Posted By: Donald
I still cannot figure why the shop would use the machine in dipstick only mode. If they are afraid of breaking fittings then they should not be in business.


Without a doubt that's why they do it the simplest and quickest way possible. You need almost no skill to do it and you don't need to mess with hoses, lines and fittings that could break and lead to return visits. I've done simple ATF dispstick pump outs with a 5gal bucket + lid, some polyethylene tubing and a shop vac. All for the cost of a case of ATF. It's an easy money maker for shops and still beneficial for the customer IMO.

Joel


I almost agree. My problem is do they explain to the customer that is will exchange only 65% of the ATF vs maybe 95% for a pan drain and cooler line flush? Do they charge a lot less since they do not exchange a high percentage of the fluid.

The real kicker is if one wanted to exchange OEM fluid with some expensive synthetic like Amsoi. When the fluid is $8.00 - $9.00 QT you need the most efficient method possible, and that is certainly NOT the dipstick method.

 

[ZZman]

Since I didn't really understand the process before I got it I would probably ask for a cooler flush next time. Price is the same there, it just takes longer.

I contacted Robinair Tech support and asked them how efficient the dipstick method was. He could not give me any hard numbers as to how effective it is in exchange percentage.

 

[Donald]

I think my numbers are reasonably close assuming your pan holds 4 out of the 14 total quarts. You can go onto the Amsoil website, look up your vehicle and it will tell you total and pan capacity.

I would think a place should be able to do a pan drain and refill followed by a cooler line flush in under 30 minutes. Much is gated upon how fast the transmission pump pumps ATF out the cooler line, in the case of my Camry it seemed about 1 QT/minute, although I cannot say I timed it with a watch.

Did the place go through all the gears, staying about 10 seconds in each gear?

 

[ZZman]

I did go thru all the gears but not for 10 seconds.

 

[PT1]

I have done dipstick drain/fill flushes for years with several vehicles with excellent results using a motive fluid extractor. Very easy to do and on some 11qt transmissions can get about 5 qts out on the first drain. Then 2-3 more drains until I get to 90% new fluid and done. Normally with an 11-12 qt trans I will do four 4qt drain/fills and call it good. If the trans has a filter then I will have the filter changed every 50k.

My old Honda CRV called for 3 drain fills as a flush in the manual. It took 3 qts per drain.

Note: With ALL vehicles I did drive them at least 2-3 miles in between each drain/fill. Some I drove 1 day and drain filled every night for a week. It only takes about 10 minutes when the oil is hot. Way easy.

 

[AzFireGuy79]

Why not just perform a cooler line flush. Its more effective hands down? Just curious. To each his own.

 

[Big Jim]

Originally Posted By: AzFireGuy79
Why not just perform a cooler line flush. Its more effective hands down? Just curious. To each his own.


It is more effective. Sometimes it just isn't needed, so the easier multiple drain and refill makes sense.

 

[ZZman]

It would seem easier to me to just do it all in one shot than multiple times.

 

[Donald]

Originally Posted By: PT1
I have done dipstick drain/fill flushes for years with several vehicles with excellent results using a motive fluid extractor. Very easy to do and on some 11qt transmissions can get about 5 qts out on the first drain. Then 2-3 more drains until I get to 90% new fluid and done. Normally with an 11-12 qt trans I will do four 4qt drain/fills and call it good. If the trans has a filter then I will have the filter changed every 50k.

My old Honda CRV called for 3 drain fills as a flush in the manual. It took 3 qts per drain.

Note: With ALL vehicles I did drive them at least 2-3 miles in between each drain/fill. Some I drove 1 day and drain filled every night for a week. It only takes about 10 minutes when the oil is hot. Way easy.


You are really doing multiple drain and refills of the pan but doing it by the dipstick. The machine mentioned does it quickly while the engine is running and is doing it 1 QT at a time, and probably does it relatively quickly so the customer does not need to wait too long while its done.

 

[Donald]

Originally Posted By: Big Jim
Originally Posted By: AzFireGuy79
Why not just perform a cooler line flush. Its more effective hands down? Just curious. To each his own.


It is more effective. Sometimes it just isn't needed, so the easier multiple drain and refill makes sense.


Multiple quick drain and refills of the pan don't make sense unless its difficult to get the cooler lines apart to do a cooler line flush. You waste ATF trying to get to a decent percentage of the ATF replaced. They make even less sense as the cost of the ATF goes up (synthetic).

Now if you are just trying to refresh the ATF every 15K to 20K miles and are only doing a single drain and refill, then it might make sense.

So the quoted statement really does not make sense. If multiple drain and refills are needed, then a cooler line flush is needed and makes more sense and take less time and is more green.

 

[Big Jim]

As I think about this some more, I too would be a little suspect of the dipstick only "flush".

One of the shops I was in had a power steering flush machine that did a similar thing. The device had two straws, one that sucked out old fluid and one that injected new fluid. Both were inserted into the power steering fluid reservoir, with the intent of the suction one to be pointed to the inlet. We were seldom able to obtain a clean flush using that machine. I don't know who made the machine, but it was provided by BG.

I would need to see the results of the Robinair trans flush machine to determine how well it worked.

 

[Donald]

The machine mentioned here only had a single tube going down the dipstick. There must be some residual fluid (old or new) left in the dipstick tube when it changes cycles. Can that be good?

 

[AzFireGuy79]

Either way this method is going to leave old dirty fluid in the trans. No thanks. Good enough is not for me. I will always flush my transmisssions. Diluting is not the proper approach when changing fluids. Do it yourself cooler line flush or T-Tec.

Donald- Good points on the drain and refill. Thats what I was hinting, at but was too lazy and tired to type it out!

 

[demarpaint]

I've done the cooler line flushes with good results. It takes a little time but is worth the effort. What I'm not liking now is some of the newer cars and SUV's have a plug in the transmission tube and no dipstick. They don't want the quick lube places working on them, and the DYI'er. I guess when the time comes for me to flush the Jeep transmission I am going to have to measure exactly how much fluid came out, and just add than amount back.

Has anyone dropped a pan or done an exchange on one of these new cars w/o a dip stick? If so any tips, how did you check the fluid? I was thinking of going to a junk yard and getting the dipstick from an old Jeep with the same engine transmission combo?

The stick the dealership uses for the Jeep transmission comes with a chart, that refers to fluid level based on temps of the fluid, etc? This is what I was told. Sounds like you need a home equity line of credit to get the dipstick, and a degree in rocket science to refill the unit.

 

[CrAlt]

Originally Posted By: AzFireGuy79
Why not just perform a cooler line flush. Its more effective hands down? Just curious. To each his own.


Who says a cooler line flush would do a better job?

The cooler line system I saw just used the built in trans pump to do the work. Once you get down X number of qrts the pump will stop pumping because you will uncover the pickup...soooo the only thing you can do is start to add fresh ATF to restart the pumping. Now you get mixing. Never going to have a full flush this way. On chrysler Torq-flites this happens when the trans gets about 2-3qrts low. How will you ever get to 90% clean if your only draining 3qrts before having to mix in fresh ATF? You would have to waste tons of fresh fluid to get there.

With the dipstick way you at least get to suck the pan dry... Way below the pickup. If the pump can push air then the pump should push the ATF out of the trans and cooler.

That being said... Both seem like they will never do a "great" job so on my rides if i needed to do a trans flush i'ed drop the pan and drain the TC. Drop the valve body (cake on 904/727's). Then use air to push the lines/cooler clean.
That would get me a real 90% with a fresh filter and not waste fresh ATF doing it.

 

[Big Jim]

And today, just how many transmissions can you drain the torque converter on?

If the automakers would put a drain on the pan, a drain on the torque converter, and a spin on oil filter there wouldn't be all this hassle, but they don't so we need to figure out the best way to exchange fluid for the particular application.

In my mind, the cooler line flush is the premium answer for most cars. You flush until the fluid coming out is as pristine as the fluid going in. Usually the published capacity will do that although you often need a quart or two more if you started with a really dirty system. Extreme cases may take a little more.

 

[CrAlt]

Originally Posted By: Big Jim
And today, just how many transmissions can you drain the torque converter on?

I really have no idea. And since you say that im guessing only the higher end cars? All mine have it. And all after market ones that reuse the 11" OEM cores seem to still have it.

Quote:

but they don't so we need to figure out the best way to exchange fluid for the particular application.

I Agree. But it sounds like there is only 2 systems. How can they be the best for all applications? Im sure chryslers are not alone on how they cool the fluid. The return line from the cooler goes STRAIT in to the sump. No different then dumping it down the dipstick tube.


Quote:

In my mind, the cooler line flush is the premium answer for most cars. You flush until the fluid coming out is as pristine as the fluid going in. Usually the published capacity will do that although you often need a quart or two more if you started with a really dirty system. Extreme cases may take a little more.


I just dont see how you could get any ware near 90% new by just swapping in the same capacity. Your limited to what the transmission pickup can reach. You have way to much old fluid stuck in there thats getting mixed in. And I don't think "looks" is a very scientific way of judging the quality of the job.

Maybe if they had a system that sucked the pan dry via the dipstick THEN ran the exchange via the cooler line? Maybe then you could get in to the 90%'s...

 

[Donald]

Originally Posted By: CrAlt
Originally Posted By: AzFireGuy79
Why not just perform a cooler line flush. Its more effective hands down? Just curious. To each his own.


Who says a cooler line flush would do a better job?

The cooler line system I saw just used the built in trans pump to do the work. Once you get down X number of qrts the pump will stop pumping because you will uncover the pickup...soooo the only thing you can do is start to add fresh ATF to restart the pumping. Now you get mixing. Never going to have a full flush this way. On chrysler Torq-flites this happens when the trans gets about 2-3qrts low. How will you ever get to 90% clean if your only draining 3qrts before having to mix in fresh ATF? You would have to waste tons of fresh fluid to get there.

With the dipstick way you at least get to suck the pan dry... Way below the pickup. If the pump can push air then the pump should push the ATF out of the trans and cooler.

That being said... Both seem like they will never do a "great" job so on my rides if i needed to do a trans flush i'ed drop the pan and drain the TC. Drop the valve body (cake on 904/727's). Then use air to push the lines/cooler clean.
That would get me a real 90% with a fresh filter and not waste fresh ATF doing it.


Your missing the initial step of a good cooler line flush, and that is to drain the pan either by using the drain plug, drop the pan, or sucking it out via the dipstick.

Not saying all shops will do this, and certainly if all that can be done is a pan drop, that adds expense onto a flush (if you are not doing it yourself).

If one did that and did the flush via the return line, then I think one would get close to 95%, (assuming also one goes through the gears during the flush).

 

[SWHeat]

+1 on "CrAlt" missing the initial step with a home transmission flush. If doing a flush and not just an interim drain and fill (which I do every 30K), I will drop the pan, change the filter, clean the pan and magnets, replace the pan, fill the pan with 100% fresh ATF, then fill with 100% fresh ATF as needed as the old ATF is going into a 5 gal bucket via a clear tube I have hooked to the return cooler line. That way the transmission AND cooler are 90%+ clean when done. When the color going in matches the color coming out with blotter check I stop, usually 1-2 quarts over full capacity. I do this every 80-100K. I have extra cooling and also external filtration. Overkill, but I'm going for 300K on the same transmission if possible in the Prizm.

 

[CrAlt]

Originally Posted By: Donald

If one did that and did the flush via the return line, then I think one would get close to 95%, (assuming also one goes through the gears during the flush).



Yes it seems i was missing the 1st step that they do. I Agree if the shop does all those steps then it would be less of a halfarse job then just hooking up to the cooler lines OR just sucking it out the tube. I just wonder how many shops would really do it the "right" way.

I guess thats why i have problems with other people touching my cars... to much OCD maybe