changing tranny fluid bad?
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changing tranny fluid bad? My friend owns a shop and he says that if you get a GM car with 80+K on it and the fluide is still OEM original (never changed) do NOT! change the fluid. He says that the new fluid will eat the clutches alive. Did not state any technical reason but the guy seems to know what he is doing, has built many >10 second cars. Any input from the tranny gurus here? Anyone do their first tranny fluide change at 80K + and experience something like this?
I can tell you from my personal experience. I had a 98 Pontiac Grand Prix GTP. At 112,000 miles I changed the tranny fluid. I bought it with 54,000 miles on it and I'm sure that the fluid hadn't been changed at that point either. The tranny was shifting fine and had no problems with it what so ever. Before I hit 113,000 miles I had to replace the tranny. I talked to the GM mechanic about it. Not the service manager at the dealership, but the actual mechanic and asked him what he thought had happened. First thing he asked was if I had changed the fluid. He told me the detergent in the new fluid cleans the shellac off of the internal parts in the tranny and gets them flowing with the fluid through out the tranny and sticking in the solenoids and causing it to not shift.
So, I would have to agree with what you were told.
So, I would have to agree with what you were told.
I would agree with him. It's not a guaranteed failure but it absolutely can happen, I've seen it. I used to work at a Chevy dealer and we did tons of these services. You should change your fluid every 30k or so. A flush is best as it clears ALL the fluid but a service (dropping the pan) is still good.
Basically, at higher mileage - it's a crap shoot. From my actual experience, 90% of the time, you extend the life of your tranny. 10% of the time, you precipitate a failure (specifically the clutches). You'll know within a short period as your tranny will quickly begin slipping as the fresh fluid and additives eat away the varnish and deposits holding the clutches together. The reality is, if changing the fluid precipitates a failure, you were probably on borrowed time anyhow.
I'm at 90k and just flushed my tranny fluid for the second time (first was at 35k) - it was BLACK after about 50k. Tranny shifts great and was noticeably improved after each flush.
My advice: if you're at 100k or so and haven't changed the fluid yet -
Do it if you can afford a rebuild, odds are good that you'll buy yourself some time.
Don't if you can't afford a rebuild but start saving for one.
Good luck!
Basically, at higher mileage - it's a crap shoot. From my actual experience, 90% of the time, you extend the life of your tranny. 10% of the time, you precipitate a failure (specifically the clutches). You'll know within a short period as your tranny will quickly begin slipping as the fresh fluid and additives eat away the varnish and deposits holding the clutches together. The reality is, if changing the fluid precipitates a failure, you were probably on borrowed time anyhow.
I'm at 90k and just flushed my tranny fluid for the second time (first was at 35k) - it was BLACK after about 50k. Tranny shifts great and was noticeably improved after each flush.
My advice: if you're at 100k or so and haven't changed the fluid yet -
Do it if you can afford a rebuild, odds are good that you'll buy yourself some time.
Don't if you can't afford a rebuild but start saving for one.
Good luck!
Well being in the tranny bussiness for over 20 years heres what I have observed , I have seen perfect working transmissions with dirty looking fluild but working perfectly fail within hours of a fluild an filter change , Tearing them down afterward while i havent really seen the clutches come apart I have seen them badly burned , and the reason seals that had literally broken up , Generally black fluild means hardened seals , new fliud with its detergents and better viscosity and generaly the higher flow rates with a new filter just literaly break them up , But also this should be bore in mind also ,
Generally unless your a proper maintenence kinda guy , Most people dnt even think about changing there fluid till the think theres a problem and ussually there is by then , So when they change the fliud its a pointless attempt at fixing the problem way to late , Its like changing the oil because the engine starts knocking , to LATE
www.performabuilttransmissions.com
Generally unless your a proper maintenence kinda guy , Most people dnt even think about changing there fluid till the think theres a problem and ussually there is by then , So when they change the fliud its a pointless attempt at fixing the problem way to late , Its like changing the oil because the engine starts knocking , to LATE
www.performabuilttransmissions.com
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How many miles is too many miles to change the fluid in say a 99-02 LS1 A4? Is 70K miles too late for the first change(assuming the fluid looks/smells okay)
Last edited by Stanger88; Oct 5, 2006 at 05:45 PM.
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if the fluild looks and smells ok it should be ok to change it , No one can ever say that for sure but most likley (I have to say that for liability reasons lol)But it should be fine
www.performabuilttransmissions.com
www.performabuilttransmissions.com
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that honestly goes for pretty much any automatic car....happened in my mazda...never changed the fluid in 100k miles...changed it one day....3 weeks later broke.....ive heard stories about it to....almost like that crappy fluid holds everything together in a old tranny 
Sort of but actually the new fluild just cleans things out sludge under lip seals actually helping support them lol.
www.performabuilttransmissions.com
www.performabuilttransmissions.com
possibly but not so much no screens to clog or small valves to stick
www.performabuilttransmissions.com
www.performabuilttransmissions.com
And this is why everyone changes their Transmission fluid every 30k miles, like I do in both my TA's, right? 
An no one on here forgets to change their oil every 3k, and y'all all change your differential fluid every 30k as well, right?
What about your coolant?
Did everyone remember to change their power steering fluid recently?
Take care of the car and it will take care of you, including transmission fluid changes.
An no one on here forgets to change their oil every 3k, and y'all all change your differential fluid every 30k as well, right?
What about your coolant?
Did everyone remember to change their power steering fluid recently?
Take care of the car and it will take care of you, including transmission fluid changes.
Joined: Nov 2001
Posts: 34,643
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From: Schiller Park, ILL Member: #317
Originally Posted by Ouija
And this is why everyone changes their Transmission fluid every 30k miles, like I do in both my TA's, right?
An no one on here forgets to change their oil every 3k, and y'all all change your differential fluid every 30k as well, right?
What about your coolant?
Did everyone remember to change their power steering fluid recently?
Take care of the car and it will take care of you, including transmission fluid changes.
An no one on here forgets to change their oil every 3k, and y'all all change your differential fluid every 30k as well, right?
What about your coolant?
Did everyone remember to change their power steering fluid recently?
Take care of the car and it will take care of you, including transmission fluid changes.
Performabuilt whats your opinion on tranny flushes what mileage would it be a no no to do? Or if you change it quite often with 100K+ miles and always keep it fresh would a flush every once in awhile be ok for it?
If the fluild is kept change regular from the begining , I suggest one a year , then flushing is fine , Now if its never been changed and has over 60000 miles I might be leary of it a little , I have seen bad things happen to other wise perfect operating transmissions after a flush .The best rule is and most important just change the filter and replace the fluild lost once a year and that should be fine ,I mean you see these transmissions all the time with 100000 plus miles fluild never been changed black as crap and still going ,
www.performabuilttransmissions.com
www.performabuilttransmissions.com
Staging Lane
Joined: May 2006
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From: puerto rico
Originally Posted by performabuilt
If the fluild is kept change regular from the begining , I suggest one a year , then flushing is fine , Now if its never been changed and has over 60000 miles I might be leary of it a little , I have seen bad things happen to other wise perfect operating transmissions after a flush .The best rule is and most important just change the filter and replace the fluild lost once a year and that should be fine ,I mean you see these transmissions all the time with 100000 plus miles fluild never been changed black as crap and still going ,
www.performabuilttransmissions.com
www.performabuilttransmissions.com
Joined: Nov 2003
Posts: 6,216
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From: Wichita KS / Rancho San Diego
Agree with everybody. Happened to me with a 65 LeMans. Changed the fluid and the tranny started slipping. Either change it regularly or forget it. I'd say 70k is right at the border line. As performabuilt said, if it looks ok, change it.
My son's 92 Bonne has 130k and a service tech said the fluid's dirty and I need to flush it. No thanks ...
My son's 92 Bonne has 130k and a service tech said the fluid's dirty and I need to flush it. No thanks ...
Originally Posted by BLKWS.6
My friend owns a shop and he says that if you get a GM car with 80+K on it and the fluide is still OEM original (never changed) do NOT! change the fluid. He says that the new fluid will eat the clutches alive. Did not state any technical reason but the guy seems to know what he is doing, has built many >10 second cars. Any input from the tranny gurus here? Anyone do their first tranny fluide change at 80K + and experience something like this?