The trans flush debate. Pictures on Page 3 - Page 8 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat
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View Poll Results: Flush the clutch material out of the trans or not
flush the trans even if the fluid has 150,000 miles on it 20 68.97%
dont flush it, the broken down material may help the trans last longer 9 31.03%
Voters: 29. You may not vote on this poll

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Old 02-03-2007, 01:49 PM   #71
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Flushes are BAD. I have over 206k on my 93 with original engine and trans and not once did we do a transmission flush. We drop the pan every few years but that was it.

I would never do a flush on any car I would own for the reasons that have already been stated (new fluid shock, loosening of particulate). Its just not worth the risk and you never know for sure. I dont know about you, but $2,000 for a transmission rebuild is alot for me.

This is from a Cadillac perspective on the 4t80 but the idea is the same for any car:

Drop the pan and forgo the flush.
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Old 05-29-2007, 12:25 AM   #72
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you guys know how your not suppose to switch to syntheic motor oil on a high milage engine that has been running conventional oil? I think this is somewhat the same.
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Old 05-29-2007, 12:46 AM   #73
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Comparitivlely speaking, an Automatic Transaxle and standard Gasoline engine are two VERY different creatures.
Were as the Transaxle has clutches, the engine does not have fiberous material that depends on thickness and pressure to operate.
I can Agree that a flush on a highmileage Transmission can be fatal in the respect that you removed the "viscosity" from the transmission, as the suspended clutch material actually makes the fluid slightly thicker, and allows the clutch facings to be..stickier for a lack of better words, an engine that has never had Synthetic motor oil MAY suffer in the respect that it could clean the crap holding around the edges of the oil seals, weather its on the crank or valves, causing a oil burning situation or a leak. Synthetic does not burn like petroleum does, infact it has more of a tendancy to resist burning, or so Ive been taught.
Without an oil change an engine, modern or old will not survive long, where as a transmission could out live the entire car.
Alot of people here have done the Petroleum oil to Syn swap...not many people have any problems that can be DIRECTLY blamed on the new oil, however, motor oil is a commonly discussed topic on Bonneville Club, Search will head you hundreds of posts/topics, as motor oil is considerd off topic at the moment.
This thread is also a bit out-dated, call it border line.
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Old 05-29-2007, 07:50 AM   #74
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I've had no problems with flushes on either of my transmissions over 100k. And I've never seen a single trans on tis Forum in 5 years that failed because of a flush.
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Old 05-29-2007, 10:44 AM   #75
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I had a flush done @ 149k a month ago, afterwards I had issues with my TCC engaging from a stop at all.

After I put magnets on the pan, the problem stopped instantly, my guess is that crud was knocked loose, and causing low internal pressure, and the magnets held it to the bottom of the pan.

I've definetly made sure to run with the fans on anytime it gets warm now...
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Old 05-29-2007, 01:06 PM   #76
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Jason, good to hear the magnets helped you out. They seemed to help out Vital as well, though he had about 20 on his pan. lol

I am planning on dropping my pan again and adding more new fluid. After my first pan drop a couple months ago I haven't noticed any negative effects. If anything, the TCC issue seems to be slightly less of a problem.

I would not see the point in flushing my tranny at all at this point. I'll just hope it holds up for another year/30,000 miles.
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Old 05-30-2007, 11:27 AM   #77
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Originally Posted by Rogue
I just change transmissions

My advice, if the trans has high miles but is functioning properly and you have never changed your fluid, leave it be until it goes. If you change your fluid at periodic intervels then you know what your fluid is like and how much material is in your pan eveyrtime you do it so it gives you an idea on how the trans is holding up.
I finally read through this thread and Rogues suggestion sounds best to me. I have a Dodge Ram 3500 dually with the same problem. I ran for 4 years towing a Bayliner Skiboat and a 30 foot pontoon boat alot of miles and my fluid looks the same. I started researching and asking around alot and got all the opinions stated here. I decided to just add some Lucas conditioner (which I've heard good things about from quite a few people) and am leaving it alone and hoping for the best. At the new cost of Dually trucks. I will definitely be rebuilding it at some point. I guess the best thing is to regularly change the fluid and not get to the point the thread'* about.

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