tranny flush with high mileage?
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1,315 Posts
How about just dropping the pan and changing the filter and adding just that much (7 quarts IIRC) new fluid. Then in a few months you can drain the pan and change that much again. Whatever you do, I wouldn't have a machine flush done on it.
Joe
on edit: I didn't answer your question, yes I believe this is true.
Joe
on edit: I didn't answer your question, yes I believe this is true.
I don't believe it's true. It's an old mechanic's tale.
What often happens is that people ignore their transmission until it gets high miles, and then problems start. They try changing the fluid, but the trans dies. The trans would have died just as fast with the old fluid. It was already dying when they changed the fluid. They didn't work on it until it had problems, but it was already too late. The new fluid couldn't save it.
If there is nothing wrong with the trans new fluid can only help it. There is also nothing wrong with a machine flush. They don't flow fluid backwards, and they don't use high pressure. It simply removes the fluid from the cooler line and replaces it with new fluid.
Or you can do it yourself with this:
http://www.thedieselstop.com/faq/1999faq/Maintenance-AutoT.htm
What often happens is that people ignore their transmission until it gets high miles, and then problems start. They try changing the fluid, but the trans dies. The trans would have died just as fast with the old fluid. It was already dying when they changed the fluid. They didn't work on it until it had problems, but it was already too late. The new fluid couldn't save it.
If there is nothing wrong with the trans new fluid can only help it. There is also nothing wrong with a machine flush. They don't flow fluid backwards, and they don't use high pressure. It simply removes the fluid from the cooler line and replaces it with new fluid.
Or you can do it yourself with this:
http://www.thedieselstop.com/faq/1999faq/Maintenance-AutoT.htm
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6,005 Posts
I would follow Mountainman's suggestion. This is not a Mechanic's tale. I have talked to a few different trans shops that have seen this happen, sure it could be there was another problem and this was a attempt to fix it, but sometimes the crud in the fluid is keeping the thing from leaking and other problems. I am not a trans guy to know the details of what exactly happens, but I have heard this to often. There is another post on here yesterday about a guy who asked the same question. He didn't wait to hear our reply, which was don't change it, and now he has a bad slipping problem. The best thing is regular maintenance and then you can't blame a failure on a fluid change. Are you saying you went almost a quarter million miles and never changed the trans fluid?
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10,487 Posts
I also see some merit to that, if there is stuff gunked up in there, then the new fluid, (Transmission fluid is a very "High detergent" oil really.) May loosen stuff that is setting there causing no trouble at the time to start circulating through the trans, causing trouble, that may or may not have showed up without the flush... I think it is kind of a "Crap shoot" really.
I have seen it too. Its fine till its changed then..boom..Its goes out. All the crap that was sitting around in there gets broken loose by the new fluid and starts causing problems with the valve body. Clogs up passages, and makes valves stick, causing it not too shift right. Dont know about the flush though. It may take all that crud out ..??
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217 Posts
Biggest mistake I've ever made in the automotive world was changing the tranny fluid on my car with over 200K miles. After the fluid and filter change, she just wasn't the same. Slipped something wicked! When I finally had the tranny rebuilt, the shop told me that the new ATF I put in was so thin and slick, the tranny just couldn't handle it. So, my 2 cents-- if your trans is fine, leave it be!!
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883 Posts
I just did this on my new to me 99 with 230k on it. I had no service history on the vehicle so i just drained the pan , changed the filter and did a shift kit /ubbthreads/images/graemlins/biggrin.gif. Next oil change in 3k i drained the pan again. so far so good and the trans liked the added line pressure and shifts really smooth.
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1,315 Posts
Change it, just don't change it all at the same time. I wouldn't keep running the dirty fluid in it. And I still wouldn't power flush it.
Joe
Joe
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16 Posts
i've been told by a few auto tranny guys (professional shops, not just guys building them in their garages) that if the fluid looks and smells good (not burnt), don't touch it. i'll trust them. doesn't mean you have to.
I had 64,000 miles on mine when I did the first trans flush.....2 weeks later Ford rebuilt it under warranty due to 1st-2nd shift slippage, but I'm not sure though if Uncle Dildo's used Mercon(requested) or Mercon V fluid when I had the trans flushed???? /ubbthreads/images/graemlins/shrug.gif
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275 Posts
My truck when purchased 3 months ago showed 97,500 on the clock. I'm pretty sure it was never changed. No apparent problems, I decided that I would just go for it, and if it went out that meant it was going to go out anyway. So far, 3000 miles later and 2 long distance tows, no problems. THAT SAID, I was a mechanic in my prior life, and I remember one car in particular that came in for a transmission service. My boss (I was a junior woodchuck at the time) told me to save the old fluid in a clean container. When I asked him why, he told me that it was insurance, because the car had high miles and had never been serviced.
Sure enough, after the service, on the test drive, the transmission showed signs of slippage. We brought the car back in, drained out the new fluid, put the OLD fluid that we had saved back in, and politely told the customer that his transmission was worn beyond service-ability and that he could continue to drive it with the OLD fluid as long as it worked, until he could come up with the funds for a new tranny. I worked at that shop for 7 years. The old man continued to bring the same car in for oil changes and other usual things and never replaced the transmission in that time.
My boss told me that the old clutch/friction material gets suspended in the fluid. If worn excessively, the clutchs need that friction material to function. By replacing with new fluid, a lot of the old friction material is gone, hence it starts to slip. It just means it was worn out to start with, but by leaving the old fluid in, you might buy some time. I remembered that lesson, and saw it many more times in my life. So it is not an old wives tale, or even an old mechanics tale. What it does mean, is that the transmission was worn to begin with. Changing fluid on a healthy high mileage trans is fine. Changing fluid on a worn out, but otherwise functioning trans, may cause it to go out completely sooner than it would have with the old fluid in.
The night I changed my fluid in mine a few weeks ago, I sat there and looked at it for over an hour wondering if I was making a $3000+ mistake by changing the fluid. So far so good. I guess it wasn't worn out.
Hope this helps...
Randy
Sure enough, after the service, on the test drive, the transmission showed signs of slippage. We brought the car back in, drained out the new fluid, put the OLD fluid that we had saved back in, and politely told the customer that his transmission was worn beyond service-ability and that he could continue to drive it with the OLD fluid as long as it worked, until he could come up with the funds for a new tranny. I worked at that shop for 7 years. The old man continued to bring the same car in for oil changes and other usual things and never replaced the transmission in that time.
My boss told me that the old clutch/friction material gets suspended in the fluid. If worn excessively, the clutchs need that friction material to function. By replacing with new fluid, a lot of the old friction material is gone, hence it starts to slip. It just means it was worn out to start with, but by leaving the old fluid in, you might buy some time. I remembered that lesson, and saw it many more times in my life. So it is not an old wives tale, or even an old mechanics tale. What it does mean, is that the transmission was worn to begin with. Changing fluid on a healthy high mileage trans is fine. Changing fluid on a worn out, but otherwise functioning trans, may cause it to go out completely sooner than it would have with the old fluid in.
The night I changed my fluid in mine a few weeks ago, I sat there and looked at it for over an hour wondering if I was making a $3000+ mistake by changing the fluid. So far so good. I guess it wasn't worn out.
Hope this helps...
Randy
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70 Posts
I just had my tranny flushed at 136,000 miles and at 139,000 miles, I have no tranny loeft. It's completely shot. No forward or reverse gears, burnt fluid, etc. It was the 2nd flush I'd had done. The 1st was at 75,000 miles. It's at the Ford dealer getting diagnosed as I type this. I'm thinking of going to an ATS. Anyone have an opinion on them?
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70 Posts
Which one is considered the better tranny? Why?
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