Problems after tranny flush??
03-12-2005, 06:20 AM
#1
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Posts: 25
Problems after tranny flush??
I've received conflicting advice on flushing the automatic tranny of a high mileage car, particularly when the service history is unknown. I've heard that if this has never been done before, there may be "stuff" in there built up around the seals. Removing this stuff may result in leaks. I heard the same thing about switching to synthetic motor oil but I did that at 113K miles with no issues. Please share you experience (or any advice) with flushing your tranny after 100K miles, and who performed the service (stealer, aamco, jiffy lube, bg shop, etc.). Thanks.
03-12-2005, 06:46 AM
#2
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Posts: 708
i flushed mine aroud 100k but i was also doing the drain and refill every 15k miles before that...either way now i have a vb mod and tranny cooler with 150k miles and still going strong. Guess it all depends on the tranny condition but if i were you i would just stick with the drain and refill. do that about 4 times in a month and most of your fluid should be new
03-12-2005, 07:41 AM
#5
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Join Date: Sep 2004
Posts: 70
I have your answer, and I think my advice comes from a pretty good source: The guy's name is Pat Goss and he has a weekend radio and television show in the Washington, DC area, owns a big shop, and he has also been the guest mechanic on the public-broadcasting service (PBS) television show Motorweek for years. I think he knows a thing or two about cars.
This is what he has to say on this topic:
a) if the fluid is still clean and pink like new fluid, then it is o.k., and ADVISABLE, to change it regardless of mileage. He advises paying a shop to use a flush machine, specifically by BGK, not just a drain and fill; BUT
b) if the fluid is dark/discolored and it smells burned, then LEAVE IT ALONE.
He says to leave it if burnt because the burned smell comes from varnishes that have developed as a result of the old fluid being worn out. This varnish has coated everything in the transmission and when you flush the system you work the varnish off all the parts, which causes two problems. 1) the varnish was tightening tolerances in the [worn] tranny, so with the varnish gone, there will be a looser fit between parts. This, for example, may result in clutch slippage (yes, automatic transmissions have clutches), or high pressure hydraulic pistons/solenoid malfunctioning; 2) the dislodged varnish/particles can now be pumped through the transmission (if not fully flushed out, which is tough to accomplish), and cause wear at a rapid rate, causing failure shortly down the road.
Ultimately, fluid in an automatic transmission should always look like it did the day it was poured in - clean and pink. I know own a '95 maxima with a 5spd, but my old car was an '84 Mercedes 300D. I changed the fluid and filter once a year, and even though the tranny was 20 years old, the fluid looked the same when I drained it as it did when I poured it in.
I could never understand why people neglect their auto trannys!? They are such high-precision components; they should be serviced and treated accordingly! Changing the fluid once a year or every 30k won't kill people.
I hope this helps and makes sense.
GregS
This is what he has to say on this topic:
a) if the fluid is still clean and pink like new fluid, then it is o.k., and ADVISABLE, to change it regardless of mileage. He advises paying a shop to use a flush machine, specifically by BGK, not just a drain and fill; BUT
b) if the fluid is dark/discolored and it smells burned, then LEAVE IT ALONE.
He says to leave it if burnt because the burned smell comes from varnishes that have developed as a result of the old fluid being worn out. This varnish has coated everything in the transmission and when you flush the system you work the varnish off all the parts, which causes two problems. 1) the varnish was tightening tolerances in the [worn] tranny, so with the varnish gone, there will be a looser fit between parts. This, for example, may result in clutch slippage (yes, automatic transmissions have clutches), or high pressure hydraulic pistons/solenoid malfunctioning; 2) the dislodged varnish/particles can now be pumped through the transmission (if not fully flushed out, which is tough to accomplish), and cause wear at a rapid rate, causing failure shortly down the road.
Ultimately, fluid in an automatic transmission should always look like it did the day it was poured in - clean and pink. I know own a '95 maxima with a 5spd, but my old car was an '84 Mercedes 300D. I changed the fluid and filter once a year, and even though the tranny was 20 years old, the fluid looked the same when I drained it as it did when I poured it in.
I could never understand why people neglect their auto trannys!? They are such high-precision components; they should be serviced and treated accordingly! Changing the fluid once a year or every 30k won't kill people.
I hope this helps and makes sense.
GregS
03-12-2005, 08:10 AM
#6
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Join Date: Apr 2004
Posts: 25
Thanks Greg, I listen to Goss's Garage all the time - excellent show. When my wifes 2002 Civic started having minor problems with tranny slippage, I took his advice and did a BG flush. Within a week the problem was much worse. I don't want to confuse cause and effect, as it may have happened anyway. Right now I'm not having any problems with my max shifting (other than the hard 1-2), and the fluid looks clean. I just don't want to cause myself problems. I think I just want to hear some other people say they did it with no resulting issues.
03-13-2005, 01:44 AM
#8
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Originally Posted by Julchen
Ultimately, fluid in an automatic transmission should always look like it did the day it was poured in - clean and pink. I know own a '95 maxima with a 5spd, but my old car was an '84 Mercedes 300D. I changed the fluid and filter once a year, and even though the tranny was 20 years old, the fluid looked the same when I drained it as it did when I poured it in. GregS
03-13-2005, 06:05 AM
#10
Originally Posted by 97MaximaSE
mt fluid has never darkened since ive had the car....and ive done about 8 drain and refills and one flush
Manual trannies are VERY different. No clutch packs, torque converters, valve bodies, etc...
03-19-2005, 07:40 AM
#12
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Join Date: Sep 2004
Posts: 70
Eturnl> No, the fluid in my 20 year old transmission didn't darken. Why should it? You are confusing your experience with motor oil. Motor oil changes color because you are combusting fossil fuel in your engine which dumps tons of junk into the oil. Engine oil isn't changing color from parts wear in your engine. Likewise, fluid in an automatic transmission shouldn't change color because there is no combustion. Consequently, it would only change color if, for example, clutch packs are wearing and dumping particles into the fluid, or the transmission is overheating and burning up the fluid (turning it dark). If either of these problems are occurring, and your fluid is consequenlty changing color, you have serious problems. That is why Pat Goss says not to change fluid if it is very discolored and smells burnt. Those two factors are A BIG RED FLAG that you have a transmission that is VERY, VERY SICK. People don't know this. They think, "oh, its dark like old engine oil, so I'll change it and everything will be fine." Then their tranny dies and they get pissed because "it was working fine before I flushed the fluid." And then the rumors and wive's-tales start. Get it????
Greg
Greg
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