Auto Transmission Flush
- Thread starter insomniac
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Are you talking chemical/solvent flushes or fluid exchanges?? Both of those could be referred to as "flushing".
The exchange method shouldn't do a darn thing except in the most neglected of transmissions. The solvent flush is a crap shoot, I think. It can surely devarnish sticking valves and whatnot ..but can also have nasty side effects. Debris can migrate to unwanted places.
The exchange method shouldn't do a darn thing except in the most neglected of transmissions. The solvent flush is a crap shoot, I think. It can surely devarnish sticking valves and whatnot ..but can also have nasty side effects. Debris can migrate to unwanted places.
Gary,
The term I hear is "back-flushing". I presume that's fluid exchange, where the old ATF is pumped out as fresh ATF is pumped in?
What about an ATF drain & fill? Is that effective? Some say it’s pointless since it only gets out about half of the ATF, the rest being in the torque converter, valve body…etc. So, the old fluid instantly contaminates the new ATF.
But, isn’t it effective if you do it regularly from the beginning, ie. new car/transmission?
[ May 01, 2006, 03:14 AM: Message edited by: insomniac ]
The term I hear is "back-flushing". I presume that's fluid exchange, where the old ATF is pumped out as fresh ATF is pumped in?
What about an ATF drain & fill? Is that effective? Some say it’s pointless since it only gets out about half of the ATF, the rest being in the torque converter, valve body…etc. So, the old fluid instantly contaminates the new ATF.
But, isn’t it effective if you do it regularly from the beginning, ie. new car/transmission?
[ May 01, 2006, 03:14 AM: Message edited by: insomniac ]
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The term I hear is "back-flushing". I presume that's fluid exchange, where the old ATF is pumped out as fresh ATF is pumped in?
Most exchange methods do just that...they exchange the fluid. One setup, in the earlier years of the practice, had a piston seperating the new fluid from the old. As the old fluid was pumped out ..it would pump the new fluid in via the cooling lines.
Nothing wrong with this at all. Again, it should be done while the trans is in good shape ..not as a "repair" attempt.
What about an ATF drain & fill? Is that effective? Some say it’s pointless since it only gets out about half of the ATF, the rest being in the torque converter, valve body…etc. So, the old fluid instantly contaminates the new ATF.
It works too. It's not as effective ..but it's what's been done for a very long time. You just need to do it a little more often to get the same effect.
..and yes, if you do it regularly from the beginning it's an effective maintenance techinque.
..but you can do both and be very happy about the whole thing. You can unhook your cooling lines ..pump out the sump ...pull the pan ..clean it ..change the filter ...button it back up ..fill it and then turn on the engine and displace the remaining used fluid. You just need to know the total dry capacity of the trans (or guess at it).
Most exchange methods do just that...they exchange the fluid. One setup, in the earlier years of the practice, had a piston seperating the new fluid from the old. As the old fluid was pumped out ..it would pump the new fluid in via the cooling lines.
Nothing wrong with this at all. Again, it should be done while the trans is in good shape ..not as a "repair" attempt.
What about an ATF drain & fill? Is that effective? Some say it’s pointless since it only gets out about half of the ATF, the rest being in the torque converter, valve body…etc. So, the old fluid instantly contaminates the new ATF.
It works too. It's not as effective ..but it's what's been done for a very long time. You just need to do it a little more often to get the same effect.
..and yes, if you do it regularly from the beginning it's an effective maintenance techinque.
..but you can do both and be very happy about the whole thing. You can unhook your cooling lines ..pump out the sump ...pull the pan ..clean it ..change the filter ...button it back up ..fill it and then turn on the engine and displace the remaining used fluid. You just need to know the total dry capacity of the trans (or guess at it).
Good advice Gary Allan. If the transmission is neglected don't do a back flush. Either use a fluid exchange machine, many places use these, or simple drain and fill. If doing a drain and fill more than one may be necessary to bring the fluid back to specs by the time it mixes with the old stuff. Don't forget about the filter, change it.
Doing both are my preference as well because on a FWD car, transmission is most critical component of the vehicle.
Shortly after I purchased my car last year, a simple drain/fill/filter replacment was performed.
Two weeks ago that procedure was repeated with a road check to adequately mix new fluid with old. This was done because of filter replacement and fluid exchange machine requires a transmission that's full of fluid. Subsequently, a complete machine fluid exchange was completed using new Mobil 1 ATF.
Fluid exchange machine will generally exchange approximately 90-95% of fluid.
Very satisfied with results.
[ May 01, 2006, 11:24 AM: Message edited by: Iain ]
Thank you, folks, appreciate all the responses.
With regards to the trans. filter, do all transmissions have a non-permanent filter, ie. old filter discarded for a new one, like an oil filter & air filter? Or, are there transmissions that have a non-removable one that can basically be cleaned only through a back-flush?
With regards to the trans. filter, do all transmissions have a non-permanent filter, ie. old filter discarded for a new one, like an oil filter & air filter? Or, are there transmissions that have a non-removable one that can basically be cleaned only through a back-flush?
Not all automatic transmissions have replacable filters, Ford Contour/Mystiques come to mind.
I can only rely on my personal experience in the shop. On transmissions with replacable filters and a drainable torque converter, forget the fluid exchange or flush and replace all fluid and replace the filter. Contrary to popular belief I have yet to see a fluid replacement machine that hooks up to cooler lines replace all of the fluid. Some mixing occurs during the exchamge. On transmissions that do not have a drainable torque converter, a fluid replacement machine is the best option. I always like to drop the pan just to replace the filter and more importantly have a look in the pan to see what is there. I have never seen a machine that flushes a transmission with any sort of solvent.
I can only rely on my personal experience in the shop. On transmissions with replacable filters and a drainable torque converter, forget the fluid exchange or flush and replace all fluid and replace the filter. Contrary to popular belief I have yet to see a fluid replacement machine that hooks up to cooler lines replace all of the fluid. Some mixing occurs during the exchamge. On transmissions that do not have a drainable torque converter, a fluid replacement machine is the best option. I always like to drop the pan just to replace the filter and more importantly have a look in the pan to see what is there. I have never seen a machine that flushes a transmission with any sort of solvent.
The BG trans flush machines use their own brand of cleaner chemical that's added to the old ATF before it's flushed, then a can of "conditioner" that's added after the flush is performed.
Not all transmissions have a removable filter. Most import brand vehicles such as Toyotas and Hondas do not. They have a screen that is up in the valve body and is unreachable unless the transmission is being rebuilt. Many, but not all, domestic brand vehicles have a replaceable filter. It costs around $30-40 for filter and gasket. There seems to be some debate as to the necessity of the replacing the filter. Its cheap to change and I think silly not to. However, many people change their filters with 100K or more and say they were no where near clogged. I don't think the filter needs to be changed every time the transmission is serviced if you choose to do a fluid exchange. Local Ford dealer charges $180 for filter change and completer fluid exchange, $140 for just the fluid exchange, and $80 for filter change and refill. They put it MC Mercon V. Most shops use BG or Wynn's machines which you can learn more about at their websites. I have heard of flush machines with so much force that they blow the filter out of its clips and it causes problems with the fluid pick up from the pan. Since an exchange machine uses the transmission pump to circulate the old fluid out and the new fluid in there is no danger of there being too much pressure on the transmission. Don't believe that junk about back flushing the filter. If a shop tries to tell you that find another shop. The correct answer is to replace the filter if it is replaceable. Would you back flush an oil filter? A fuel filter? No you replace it, especially since its so cheap to. If you back flush a transmission where does all that junk go? Back into the transmission and probably right back into the filter that wasn't changed. Usually, this kind of nonsense comes from "Quickie Lube" places that have neither the expertise or time to drop the pan, clean the pan, put the new filter (that they don't have in stock and had to order from NAPA while your car is on the lift and it took an hour to show up) in correctly, install the new or in some cases old pan gasket and properly tighten the pan up so it doesn't leak without strpping the pan bolts. That's why they try to talk you into not changing the filter and tell you that back flushing is fine. They push cars in and out in "10 minutes or less" no way they're going to take the time to it right. Take your vehicle to the dealer and explain what service you want performed or find a good shop that will take the time to it right.
Timely discussion for me. I recently had my '99 Windstar w/106k serviced. Had them do both a pan drop/filter change and flush/fill. I'm now taking my daughters '97 Galant w/132k (recently purchased) in next week to have the same done to it. It's a pricey procedure for both, but well worth the peace of mind at the 100k +/- interval (I have a flush/fill done around 50k).
We had a 95 Plymouth Grand Voyager. Everyone told me those cars were notorious for the transmission dying at 114,000 miles. So, I had a dealer service a couple of times. The last one was a transmission flush which I later found out meant 8 of the 12 quarts of fluid got replaced.
Finally, after a bunch of research I found out about the transmission filter under the car. At 90,000 miles I bought a new filter at Carquest for a fraction of what the dealer wanted, dropped the pan, made a big mess, replaced the filter and gasket, filled with 4 quarts of the correct fluid and took off. I could feel the difference. The old filter had lots of visible crud on it. I also cleaned crud off the pan.
I sold the car to a real estate agent at 125,000 miles 2 years ago. I saw it drive by my office yesterday. Its go to be up to at least 160 now.
Knowing the correct maintenance pays.
Finally, after a bunch of research I found out about the transmission filter under the car. At 90,000 miles I bought a new filter at Carquest for a fraction of what the dealer wanted, dropped the pan, made a big mess, replaced the filter and gasket, filled with 4 quarts of the correct fluid and took off. I could feel the difference. The old filter had lots of visible crud on it. I also cleaned crud off the pan.
I sold the car to a real estate agent at 125,000 miles 2 years ago. I saw it drive by my office yesterday. Its go to be up to at least 160 now.
Knowing the correct maintenance pays.
Best method I've found:
1. disconnect a trans cooler line, start the car, and let the fluid run until it stops. Shut off car immediately.
2. Drop pan and replace filter. Clean magnet. Some cars are not serviceable here.
3. After buttoning up pan, refill transmission.
4. Repeat step 1.
5. Refill transmission.
Only use fluid that is "approved" for your specs, which will protect your warranty. Avoid those that are only "recommended" or "have been tested". These one size fits all fluids are a crap shoot.
1. disconnect a trans cooler line, start the car, and let the fluid run until it stops. Shut off car immediately.
2. Drop pan and replace filter. Clean magnet. Some cars are not serviceable here.
3. After buttoning up pan, refill transmission.
4. Repeat step 1.
5. Refill transmission.
Only use fluid that is "approved" for your specs, which will protect your warranty. Avoid those that are only "recommended" or "have been tested". These one size fits all fluids are a crap shoot.
sambojoho,
Won’t that destroy the transmission? Fluid is emptying while the transmission is running. There’ll be a point between when the fluid is too little and empty that transmission damage will occur.
Iain,
Is that what you were implying, too, with that emoticon?
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