What's the consesus on an automatic transmission fluid flush...?

BGCarrera32 · 02-18-2007, 10:17 AM

I have a 2000 Ford Windstar with 74,000 miles. I do regular oil changes, but have never had the automatic transmission fluid flushed. Overrated or something that should be done? No problems per say...

Thanks-
BG

pwd72s · 02-18-2007, 10:46 AM

I had it done to our Ford Ranger after a routine trans fluid change resulted in our local mechanic finding sludge in the pan. I then went to a specialty shop in a nearby town, who did the complete flush. No problems since, and we were about to dump the Ranger after the first news. I trust the guys at the (NOT a chain) transmission specialty shop. Owned by an ex boyfriend of a cousin of mine...they dated some 25-30 years ago. Hmmmm...they're both single now. I wonder....

Anyway...yeah, go for the flush, it can help. Choose your shop carefully though...ask around. Local knowledge thing.

dagriff · 02-18-2007, 11:10 AM

@ 74,000 miles if the fluid is still fairly clear, you are probably ok.
However, in a high mileage tranny with really dirty fluid it's only the crap & varnish stopping it slipping. Highly detergent fluid or flush will do a great job cleaning it out, but very often the trany will start slipping soon after.
The company I work for has over 4,000 vehicles (light truck)with auto, we now only change the fluid at 60,000 kms (to keep the warranty boys happy) then not again.
A US company with a similar size fleet (all cars) did a study over several years and found it cheaper not to do a fluid change ever and just pay for the odd one that went T.U. They only kept cars until 100,000 miles, we keep our truck for 10 years or 500,000 kms, so we budget for at least one tranny in the life cycle anyway.
For the individual car owner I would say do it as often as you want, but if you leave it to long don't do it at all.

M.D. Holloway · 02-18-2007, 11:18 AM

It will not remove varnish. Any additive that you put in has the potential to actuall hurt you - thats for automatic trannys, sticks are different. Trust me, we spent many years trying to come up with a good flush for an automatic. ALl other oil lubricated systenm including greased systems we were able to show great strides but the automatics are a different animal. Change the fluid every 50,000 and you should be fine.

Dantilla · 02-18-2007, 12:49 PM

My wife's jeep started having tranny problems, so I dropped the pan to find burnt fluid, and the magnet buried under enough sludge to qualify as an EPA Superfund site.

I don't think the flush does much more than a regular fluid / filter change.

Note to self: I said regular fluid and filter change. Not wait until the tranny is acting up.

Zeke · 02-18-2007, 01:00 PM

Of course Mike is an authority, but I'll back him up on this. Change fluids regularly but leave the stubborn stuff to stick to wherever it is. Loosening up a bunch of junk only to find a ball valve or passage may bring about a failure you wouldn't have had if you'e left it alone. Dropping the pan and changing the filter is always a good idea, even at 25K or sooner if you tow or otherwise work the unit hard.

fastpat · 02-18-2007, 01:47 PM

I'm a big advocate of auto tranny flushes, with auto tranny fluid only. I disconnect the return line from the tranny cooler built into the radiator on most American cars and trucks, install a short metal line with a 4-6 foot piece of fuel hose on it, and use the engine to pump the old tranny fluid out. You start the car, pump about 1-2 quarts of fluid out into a bucket, shut the engine off, then replace that fluid. Do this repeatedly until you've put in about the total tranny capacity. That procedure replaces all the flud including that in the torque converter. Works very well.

wreckersteve · 02-18-2007, 02:24 PM

Flush is a good thing. The machine the shops use are only putting in at the same rate it comes out at. Droping the pan only get 5 or so qts out. Read your owners manual and you will see that the hold about 14. So the old way leaves 75% of the old stuff with partics still flooting in it to wear the tranny out.

notfarnow · 02-18-2007, 03:18 PM

Quote:

Originally posted by dagriff
However, in a high mileage tranny with really dirty fluid it's only the crap & varnish stopping it slipping. Highly detergent fluid or flush will do a great job cleaning it out, but very often the trany will start slipping soon after.

I learned this the hard way a few years ago.

3 sp auto in our old Jetta was shifting hard, so the transmission shop (local chain) recommended a flush. When they were done, it wouldn't shift into 3rd. Only then does the mouth-breathing employee tell me "yeah, that happens with old transmissions. Sometimes they don't work after they get flushed."

G R E A T. Coulda lived with the hard shifting.

pwd72s · 02-18-2007, 03:32 PM

So, differing opinions here...I just want to add that the "flush" done to our ranger was with trans fluid only...NOT the "chemical flush" you see advertised. Also, the shop I used did NOT recommend switching to synthetic fluid...said I was better off sticking with the original Ford stuff.

wreckersteve · 02-18-2007, 03:43 PM

If you are having a problem it usually will not fix it. As maintence the flush is the way to go over just dropping the pan and changing the filter

TerryH · TerryH's Garage

Ensure you are getting your filter changed. Never assume it's included in any service.

fastpat · 02-18-2007, 04:18 PM

Quote:

Originally posted by notfarnow
I learned this the hard way a few years ago.

3 sp auto in our old Jetta was shifting hard, so the transmission shop (local chain) recommended a flush. When they were done, it wouldn't shift into 3rd. Only then does the mouth-breathing employee tell me "yeah, that happens with old transmissions. Sometimes they don't work after they get flushed."

G R E A T. Coulda lived with the hard shifting.

My experience is that a tranny that was slipping already, '76 chevy pickup, with overheated fluid. Flushed the fluid as I described above, result was no slippage of any kind later, lower tranny temps, and firm shifts.

M.D. Holloway · 02-18-2007, 05:56 PM

Allow me to clearify, a chem flush stands to mess stuff up - any left behind will effect the clutch. Now flushing with fresh ATF is fine but it will not remove any varnish that may have built up over time and abuse.

Also, most all ATFs are roughly the same. The specs required to hit are so tight with ATFs that their is very little anyone can do to boost them. That is not so with stick. Newer auotmatics may call out for a synthetic ATF - different animal entirely as well.

Joeaksa · 02-18-2007, 08:24 PM

My 2000 S-type has no drain plug on the tranny pan. They expect the fluid to last forever. Course this tranny has a history of problems in this model.

Am about ready to drop the pan and put new fluid in it. Car has 70,000 miles on it and thats enough for me.

Jim Sims · 02-18-2007, 09:09 PM

Quote:

Originally posted by Joeaksa
My 2000 S-type has no drain plug on the tranny pan. They expect the fluid to last forever. Course this tranny has a history of problems in this model.

Am about ready to drop the pan and put new fluid in it. Car has 70,000 miles on it and thats enough for me.

Does it have a dipstick? Some of these "sealed" automatic transmissions require a special fitting to pump the refill fluid upward through the bottom as there is no top opening through which to add fluid.

Joeaksa · 02-18-2007, 10:22 PM

Jim,

Yes it does have a dipstick from what I am told. I am looking for a pan for the puppy that has a drainplug to make it easier in the future. Believe that other makers use this same tranny and allow for draining the fluid, so put a drainplug in the bottom.

Jaguar says that auto tranny's on the new series of cars are designed to last only 50-70,000 miles. Bullcrap I say as the older ones would last a lot longer. The one in my XJ lasted 660,000 miles then was overhauled just because we were worried about it. Some of this new fangled crap and ideas are not really progress IMHO.

AFJuvat · 02-19-2007, 06:30 AM

Never seen any advantage to them.

Just stick with scheduled maintenance

sammyg2 · 02-19-2007, 07:37 AM

snake oil, scam. Not necessary unless you have too much money and can't figure out a way to get rid of it.
Just change the oil at the recommended intervals and the tranny should out-live the rest of the vehicle. Unless it's a chrysler transmission, then all bets are off. Not even a flush a day can keep one of them alive

pwd72s · 02-19-2007, 09:44 AM

One thing to think of is an aux. trans fluid cooler if your car or truck didn't come with one. This regardless of whether or not you tow. The guys at the trans shop told me part of the problem is with the radiator cooler...that today's cars run hotter coolant temps because of smog law requirements. Seems that transmission fluids are nearing breakdown temp. even when all is operating properly. Luckily, Cindy's Ranger came with an aux. trans cooler. Dunno if that was standard or optional. It's a '99 XLT with the 4.0 V-6.