replacing the trans fluid harmful?
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Launching!
Joined: Jun 2013
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replacing the trans fluid harmful? I told a couple people that I made an appointment to get my fluid flushed and filled back up and they told me that that can sometimes be hard on the transmission. Is that true? I'm taking it to an experienced mechanic who has always worked on my car and been honest with me so I trust he will fill it up properly. From what I understand as long as the fluid is at the proper level nothing should be harmed. Car has 74,000 miles on it and the fluid has never been changed to my knowledge. I know getting this done is expensive cause he is actually flushing the fluid out so all the old fluid is removed, that's how he explained it. So I'd hate to spend money on something that could be damaging. Any info would be nice all I found was that it needs to be filled extremely close to the recommended amount.
I'm not an expert, first off.
But my understanding is that changing bad transmission fluid can be rough because of established wear patterns of the bad fluid. 74,000 sounds a little high, but someone with more knowledge could give you a better idea if it would be good to begin proper trans fluid exchange intervals or if it would be better to leave your old fluid in. Dex VI fluid from AC Delco is available as cheaply as $23/gallon. If you pay a place to do it for you, expect to pay well over $100 (including fluid).
The machines that actively force the fluid through the transmission is supposed to be bad for the seals and such. The machines that passively push the fluid through using the transmission pump's own power while the vehicle is running is supposed to be okay.
But honestly, changing your own fluid is super easy and takes less than 20 minutes. I've been doing it myself for years.
Unhook the cooler line from the radiator
stick a threaded barb on the fitting that's pushing the fluid from the radiator to the transmission
stick a tube on the barb
drape other end of tubing in a bucket
turn on engine to start pushing fluid through the tube and into the bucket
turn engine off at first sign of bubbles
add fluid like normal to refill pan
repeat until fluid looks clean in the tubing
add fluid to appropriate level
But my understanding is that changing bad transmission fluid can be rough because of established wear patterns of the bad fluid. 74,000 sounds a little high, but someone with more knowledge could give you a better idea if it would be good to begin proper trans fluid exchange intervals or if it would be better to leave your old fluid in. Dex VI fluid from AC Delco is available as cheaply as $23/gallon. If you pay a place to do it for you, expect to pay well over $100 (including fluid).
The machines that actively force the fluid through the transmission is supposed to be bad for the seals and such. The machines that passively push the fluid through using the transmission pump's own power while the vehicle is running is supposed to be okay.
But honestly, changing your own fluid is super easy and takes less than 20 minutes. I've been doing it myself for years.
Unhook the cooler line from the radiator
stick a threaded barb on the fitting that's pushing the fluid from the radiator to the transmission
stick a tube on the barb
drape other end of tubing in a bucket
turn on engine to start pushing fluid through the tube and into the bucket
turn engine off at first sign of bubbles
add fluid like normal to refill pan
repeat until fluid looks clean in the tubing
add fluid to appropriate level
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Itll be fine. There is no wear pattern in a fluid. If a flush causes trans issues then 9/10 there was something wrong with the trans beforehand and 1/10 the flush may have been done wrong.
^^^ yes. Putting in fresh new fluid and replacing the old will only add 'life' to the tranny,assuming there's currently nothing wrong with the tranny. Even though the trans pan filter is doing its' job,it only filters down to a certain particle size. Engine oil filters are typically 10 micron absolute,don't know the micron rating of trans filters. Particles(metal wear and clutch material) that are smaller than the filter rating remain in suspension and circulated. That 'slurry' is abrasive and does nothing to contribute to the life of the trans.
OP I have heard such rumors before as well. That replacing old fluid with new on a fairly high milage tranny would cause problems. We replaced the old fluid in my old 60e with 12xxxx miles and I never had a problem with the tranny even up until I sold it.
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I would never flush a transmission unless MAYBE it had low miles. I tried to go get it done when my car had the same miles as you. The builder/owner of the shop I took it to actually talked me out of paying him to do the job. He said he's seen more than enough evidence of transmission failures or transmissions slipping after doing a flush with the machine. He BTW has a 4th gen Camaro also. His experience however is not limited to one kind of car. He's seen it with all kinds. He told me to just do a pan/filter change. I have heard this many other places too.
So what I did was at 90k I did a ss3600 install. When I had the transmission out I stood it up on the tail and got most of the fluid out. I replaced with about 10qts of dex6 + filter and the ss3600. It was fine for almost 40k when the 2-3 shift started bouncing the rev so I got a built flt4. I would say the stock transmission held up pretty spectacular.
If I were you I would just drop the pan and do what the book says. Skip the flush machine.
So what I did was at 90k I did a ss3600 install. When I had the transmission out I stood it up on the tail and got most of the fluid out. I replaced with about 10qts of dex6 + filter and the ss3600. It was fine for almost 40k when the 2-3 shift started bouncing the rev so I got a built flt4. I would say the stock transmission held up pretty spectacular.
If I were you I would just drop the pan and do what the book says. Skip the flush machine.
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