Who do you trust to flush your ATF?

[95LEGOBW]

My favorite local shop (in Portland, OR) doesn't have the machine to fully flush the automatic transmission fluid on my 95 Outback, so I need to find another shop. I cringe at letting Jiffy Lube touch a Subaru, but I'm sure the dealer wants big bucks. Suggestions?

[Commuter]

Not the info you are looking for, but I am not a fan of the "flushes" when it comes to auto trannies.

 

I'm a proponent of the drain and refill 2 or 3 times to change out the ATF.

 

Why?

 

Flushes don't get 100% of the fluid changed out anyway; some don't even come close. Some flushes may be no better than a drain and fill.

 

Flushing can dislodge dirt and varnish and gum etc, particularly if they use some kind of cleaner fluid first. This gets into the valve body and can cause trouble big time. I've heard that Chrysler has many records on file of auto tranny failures within 200 miles after the owner did a tranny flush service.

 

Flushing costs money with questionable benefit. The DIY versions of tranny flush are risky IMO. The use of the cooling lines (which may not work if the fluid has to up to a certain temp before the ATF flows thru those lines); hooking up lines to the pump with the pan off, etc.; trying to add fluid at the same rate it is pouring out a line or a drain. Makes me shudder.

 

I know with my car, you can drain about 4L of 10L total. One change, and you have 60% old fluid left. 2 changes, and you have 36% old fluid left. 3 changes, and you have 22% old fluid left. That takes 12L. No more than the flush methods use. And you know where you stand. You can DIY. Yes, it takes a bit of time. (I'm assuming some driving / running in between to thoroughly mix fluids.)

 

Just my 2 cents.

 

Commuter

[cookie]

What do you guys think? I have always changed my automatic's oil and filter regularly and they stay pretty clean and give me a long life.

People are flushing engines too and I'm not sure that does a heck of a lot either. I wonder if you would not accomplish about the same thing by doing a few clean out fluid changes.

[gfcrane]

After reading lots of pros and cons on tranny flushes, I decided on drain and flush as the best (and cheapest) way. On my last car I bought a case of Chevron ATF and did four drain and flushes. This gets you down to almost single digit percentage of old fluid. My plan was then to do one four quart drain every six months with non-synthetic ATF. This might be a bit overboard, but it's pretty cheap insurance and is easy to do. Then I traded for a Forester and have a while before deciding what to do with it. Once I figure out how much comes out and the total capacity, I'll probably do something similar. Changing the filter would be every couple of years at my mileage.

[lmdew]

I'm in Portland for three days, out by the airport. If the micro beer is cold and you have two or three gallons of fluid, I'll do the flush for you in a matter of 30 minutes.

 

Needed:

Drain pan and wrench 19mm I think

Screw driver and a lenght of 3/8" plastic hose 2' long

 

Larry.

[SubyNoobie]

Good info, I was looking at changing my ATF soon, and this will prove helpful. I purchased a 95 Legacy with 160k miles on it, and I've been slowly been replacing neglected parts, such as rotors, brake pads, etc.

 

Yesterday I replaced my spark plug/ignition wires, and it made a WORLD of difference, as my car was hesitating/missing while idling and while trying to get up and go. Now, it runs much better.

 

I've never owned a car where the temperature guage went above 1/2, and last time I was going up a lot of hills to go camping, it went up to 3/4, so my next weekend project is replacing the thermostat, flushing and de-scaling/de-rusting the cooling system, and then filling it up with some good stuff.

 

After that, I plan on tackling the ATF, and my primary 02 sensor.. A million things.. Luckily, small. I cringe at the day that I break a rear axle or such while offroading.

[nipper]

Flushing removes all the gum that is holding your engine and transmission together. If you flush a high mialage drivetrain, you can pretty mush say goodbye to the drivetrain. Gum and such has built up in clearances that have worn over time, and they are your freind.

Same for raidator flushes on anything with high mialage.

 

My 98 legacy would get the temp gauge 1/3 of the way up on hills with ac on. The radiator was cloged, and found it far easier to replace the raidator (radiator.com) as oppsed to flushing it. Remeber when you flush it, your flushing the heater core too. It is possible to descale the inside of the heater core, and remove anything that has cloged any pinholes, or has reinforced eroded tubes.

Much easier and cheaper to replace the radiator then it is to replace the heater core.

 

nipper

[DerFahrer]

I had my grandfather's 93 Legacy wagon flushed at Aamco at 114k after taking it through treacherous moutain roads earlier this summer. So far everything's been working fine, but I think that's the last time I'll flush it.

[cookie]

that an OEM temp guage is not usually that accurate. It is not a bad idea to put a thermometer in the radiator, (be careful) put it in cold, and watch the temp rise and compare to the guage.

If your temp went up on hard pulling that is fairly normal and means the guage works. I have a Pontiac in my yard that says it is about 120 when it is parked and cold.

Cooling system service is a good idea and changing the thermostat at proper intervals is a good idea. Also inspect all the other items while you are doing it, like heater hoses and cap.

[nipper]

Actually best indication is the sooby itself. If your going up a hill, and its just you in the car, no luggage, and you have the ac on... the ac will cut out when the temp gauge reaches 3/4 hot.

Also its gotten to be an old wives tail that temp gauges from the facotory are innacurate. With aluminum engines they have gotten pretty close. Aluminum engines are not forgiving with over heating like the cats iron engines were.

Gauges tend to be most innacurate at their extreems, not in the middle range. I calibrate gauges as part of my job.

The only gauges I wouldnt trust is anything directly from GM, as they havent discovered quality control yet.

[95LEGOBW]

Thanks for all the interesting replies to my original post!

 

I had asked who, besides the dealer & Jiffy Lube, I should trust to flush the auto trans on my 95 Legacy OBW. Here's the tally on replies so far:

 

4 for "Don't flush, it's bad for your trans. Do several drains instead."

1 for "I tried flushing once and had no problems."

1 for "I'll help you drain it for a micro-brew" (thanks!)

3 helpful replies on an unrelated topic.

And, answers to the original question: zip!

 

Thanks for all the interesting replies!

 

My next question, if anyone's still following this thread: If a flush will loosen gunk in my system, but not get it all out, and thus damage the transmission, why doesn't that happen with the "drain several times" process?

 

Also, if the "drain several times" process doesn't loosen gunk, what good is it?

[nipper]

Actually my professor in transmissions in auto engineering always adv ised that you drain the old fluid, filter it yourself, put it back in, then top it off with fresh.

This may be the drain several times, not sure.

New fluid has chemicals in it that will take all the gunk thats holding your tranny together out of it. This method dilutes the fresh fluid enough so that you can have a full tranny, and not have all the varnish and gunk removers at full strength.

 

nipper

 

BTW if it was a low mialage car, i would trust anyone but jiffy lube.

[nipper]

PS

 

This is of course assuming that the filter is replaced during this time. If your not going to replace the filter, the point is moot.

Also be prepared for the "there is material/junk in the bottom of your pan, which means your clutches/transmission is dying" line.

 

nipper

[idosubaru]

when most are voting for drain and refill they are speaking of what they would do, so it's hard to recommend a place to do it for you. don't know if shops will do a drain and fill but it's as easy as an oil change basically so it's about the simplest exercise for a mechanic to complete. nobody touches my car so i'd say do it yourself. but if you can't, i'd say let anyone do it as it's a very simple procedure.

[cookie]

I always saw material worn from the clutchs and various other bits in the pan. You usually saw quite a bit of stuff in the filter also. Doing the job like that removed all of this trash from the tranny and did not send it back through the transmission like flushing would. A drain and refill won't get all this stuff, but you don't circulate it either.

I am afraid Nipper's professor and I might not argree on a few points, but this is pretty common. Folks tend to develop thier own ideas.I tend to do what the sevice manual says because it usually works and odds are they know more than me.

[mtsmiths]

Despite my constant admonition to avoid Stealerships, there ARE two exceptions in our family.

 

Transmission service and oil changes.

 

I find the costs to be close enough that I pay the extra to know that at least the tech knows which plug and fill tube goes where (it was hard to break my wife from going into Jiffy-Screwed with her 2000 Leg). When I finally pointed out that the Subaru dealer washes the car too, and all for only five or six bucks more, she went with it from then on.

 

Watch the dealer service incentive sales, you'll often find full tranny service for $49.95.

 

I figger the A/T is the car's weak link, so we don't scrimp, we do a fluid/filter change every 30,000, oil changes at 5,000. Take a bye on the offered air filters, etc.

[friendly_jacek]

I always saw material worn from the clutchs and various other bits in the pan. You usually saw quite a bit of stuff in the filter also. Doing the job like that removed all of this trash from the tranny and did not send it back through the transmission like flushing would. A drain and refill won't get all this stuff, but you don't circulate it either.

I am afraid Nipper's professor and I might not argree on a few points, but this is pretty common. Folks tend to develop thier own ideas.I tend to do what the sevice manual says because it usually works and odds are they know more than me.

 

Second that. The usual scenario with AT failing after flush is that neglected tranny starts to malfunction and owner suddenly remembers that tranny never had ATF change. The flush in these circumstance will vigourously remove dirt from clutches and seals and suddenly clutches slip and seals leak affectively trashing the tranny.

 

Doing a tranny flush in a well maintained tranny is not a very bad thing and any shop can probably do it just fine, but dropping the pan, like cookie said, will give an oportunity to clean magnets and such.