Tranny flush myth?
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TECH Resident
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Joined: Nov 2004
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From: Fort Worth, Texas
Tranny flush myth? I just turned over 100k miles I'm not sure if the original owner before me ever flushed the tranny fluid at the 50k mark. I bought it at 65k and really haven't gotten on it only a few times. The tranny doesn't slip and it feels like there is no problems at all with it. The guy at quiktrip where I had my oil changed told me that since I just turn 100k to get the tranny flushed. I told him about not knowing if it had been changed before, so he took some of the tranny fluid and said it looks like it has been changed since its still red in color. So if I have it flushed is there any chance that it could screw the tranny up or that just a myth that I keep hearing?
TECH Enthusiast
Joined: Sep 2006
Posts: 708
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From: FLORIDA
I have heard quite a few people say their high mileage tranny went out shortly after doing a tranny flush. If I were you I would only drop the pan and change the filter not a complete flush. It's not worth the risk unless you are planning on getting a new tranny soon anyways.
i also read up to where guys had problems with there trannies when they got a tranny flush. thats why ive been so hesitant on getting a tranny flush. but ive learned that u dont do the tranny flush. u just change the filter and fluid.
Staging Lane
Joined: Mar 2006
Posts: 65
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From: upstate NY
Lube is cheap, compared to buying tranny parts- the ATF has friction modifiers and all sorts of good chemistry, and it wears out- it lives in a hellish environment, with heat, friction, and slippage- It is a good idea to keep fresh fluid in there-
i have heard the same and have been hesitant to do that on my 98 blazer.The fluid is starting to turn a brownish color from age and am just going to swap filter and fluid and clean the pan.
I've heard it too but always flushed my own 100% and never had problems.
Now I don't know about the 'blood transfusion like' machines that some shops use.
I just put a huge pan under it, run a hose from fresh fluid supply to the filter intake and let it run a gallon or so through it. Maybe carefully have someone shift through all gears. The fluid usually stays red for a long time after doing this.
Now I don't know about the 'blood transfusion like' machines that some shops use.
I just put a huge pan under it, run a hose from fresh fluid supply to the filter intake and let it run a gallon or so through it. Maybe carefully have someone shift through all gears. The fluid usually stays red for a long time after doing this.
Most of the horror stories I've heard were after flushing high mileage transmissions. Something to do with the seals and stuff coming apart during the process. I think if you were to do it at a lower mileage you may be alright. But I would start with a filter and fluid change and see what happens.
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Verdad Gallardo
Joined: Nov 2003
Posts: 6,216
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From: Wichita KS / Rancho San Diego
Tranny guys I know recommend fluid + filter. But I think flushes are fine if they are a part of regular maintenance. Flushing a high mileage tranny that hasn't had regular service is asking for trouble.
In my experience, if the fluid is already brown and burnt smelling save the money toward a rebuild. It will probably die soon anyway. Changing the fluid only speeds up the process.
If the fluid is still nice and pink there should be no negative consequences to a fluid change.
If the fluid is still nice and pink there should be no negative consequences to a fluid change.
That's what I've heard too. I don't put a lot of miles on any of my cars, but I do a "fluid & filter" every other year. Used to do it every year when I had only one car, and it got a lot of miles....
Teching In
Joined: Sep 2007
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Flushing pumps oil through the torque converter which makes for a better oil change. But be careful.
Red oil with no burnt smell and your fine, Regardless of miles. Flush away.
Brown or brownish red and burnt. Don't flush. Change out 2 quarts of oil and drive your ride, don't change all your oil. Next weekend do it again. Do this 3 or 4 times.
The reason for this is the new oil loosens the clutch material that came off your clutches and gets stuck in your valve body, torque converter, casing and filter. You don't want it all coming free at once. After the 3rd or 4th time (depending on the color) change the oil and filter. If the color stays red but still smells burnt(Normal) go a head and have it flushed. You should change your oil cooler at this point regardless if you flush or not. There cheap and adds a little security. If the oil doesn't look right to you yet, change the oil and filter again. Do this a week apart to let the new oil do it's job.
Keep in mind. If your into the 2nd or 3rd 2 quart change and the trany doesn't feel right. Pull the filter right away and change it. Now this is going to sound stupid. Put the old oil back in changing out 2 quarts only. You still want the new oil to clean out all the metal and clutch material slowly.
This can get a little pricey, but it's cheaper than a trany.
Good luck.
Red oil with no burnt smell and your fine, Regardless of miles. Flush away.
Brown or brownish red and burnt. Don't flush. Change out 2 quarts of oil and drive your ride, don't change all your oil. Next weekend do it again. Do this 3 or 4 times.
The reason for this is the new oil loosens the clutch material that came off your clutches and gets stuck in your valve body, torque converter, casing and filter. You don't want it all coming free at once. After the 3rd or 4th time (depending on the color) change the oil and filter. If the color stays red but still smells burnt(Normal) go a head and have it flushed. You should change your oil cooler at this point regardless if you flush or not. There cheap and adds a little security. If the oil doesn't look right to you yet, change the oil and filter again. Do this a week apart to let the new oil do it's job.
Keep in mind. If your into the 2nd or 3rd 2 quart change and the trany doesn't feel right. Pull the filter right away and change it. Now this is going to sound stupid. Put the old oil back in changing out 2 quarts only. You still want the new oil to clean out all the metal and clutch material slowly.
This can get a little pricey, but it's cheaper than a trany.
Good luck.
I work at a Jiffy Lube. We just fill the flush machine with fresh fluid and it flushes out all the old fluid and puts in the new fluid. The only thing about just dropping the pan and changing it in there is that you are only getting the fluid out of the pan. The lines and torque conveter are left with old fluid. With a lot of miles, you are supposed to drop the pan and change the filter, as well as a flush. That's just what GM recommends.......
I recently did a flush and full fluid change on my 99' Z28 and I've had no problems. In theory there shouldn't be any problems associated with a transmission flush. I even went to a full synthetic and have had no problems. I used a BG PF5 transmission flush machine that does the entire torque converter and the coolers. I changed the filter. My transmission slips into gear easier and seems to run better. A quality fluid is also a big factor.
If the transmission is in good running shape at the time of the change, a fluid flush will not hurt anything.
If the transmission is in good running shape at the time of the change, a fluid flush will not hurt anything.
