Please Stop Doing This to Your Transmission (It Destroyed My Car)

Please Stop Doing This to Your Transmission (It Destroyed My Car)

rev up your engines today I’m gonna tell
you why you should flush the toilet in your house but not flush the
transmission in your car now for the last 52 years people are asking me
Scotty somebody’s trying to tell me I need to flush my automatic transmission
have it all flushed out and new fluid put in is that a good idea and I generally say no it’s not a good idea now the reasoning behind flushing isn’t
a bad idea realize most automatic transmissions
when you drain the pan take it off empty it out maybe three four quarts of fluid
comes out and some of these systems hold like 14 15 quarts so a bunch of the old
fluid remains inside especially inside the torque converter because it’s not
like flushing your radiator system out which is much simpler now radiators have
tiny halls that the coolant has to go through you want to keep it clean so
that all those passageways don’t get clogged up and the cooling system is
very simple you got a radiator and flows through you have a water pump that pumps it through the system goes through the jackets of the engine inside to take the
heat from the engine and then pump and dissipate it through the radiator simple
system you don’t want to clogged up a mechanical or in some cases the new ones are electric pumps they still just pump the fluid so you flushed it out you get
all the crud out you’re not gonna have any problems but automatic transmissions completely different animal here automatic transmissions are very complex inside they have electric solenoids they have tiny little passageways that go by
pressure differential you have dirt in your automatic transmission and you run
a power flush that’s power pushing the fluid through the system those tiny
little holes some of the crud could be pushed into the little holes jamming
them up I have seen hundreds of people have the transmission flush somewhere
else they bring it to me and say Scotty my transmission is slipping now or it
won’t go into gear or shifting rough and it wasn’t doing it before I had the
transmission flushed and it’s true that can easily happen the best thing to do
is to drop the transmission pan clean it all out and check
the filter the filter is there to catch most of the crud so you dropped the pan
clean the dirt out in the bottom put a new filter in then the system is good to
go if you do it regularly no when I was a young mechanic in the nineteen sixties
we would change the transmission fluid and filter every thirty thousand miles
the fluid wasn’t as good the transmissions weren’t as good and it had to be done more often now today the transmissions are better the fluid is
better I would still change it every sixty thousand miles or so in any
vehicle and for heaven’s sake don’t listen to those people that say a lot of
transmission fluid in a modern car its lifetime fluid you never need to change
it then your ask an engineer what does a lifetime fluid mean and an honest one
will respond well it means that the fluid is good for the lifetime of the
transmission well ask about the warranty is usually it’s sixty thousand miles or
something hey I don’t want to transmission that after sixty thousand
or eighty thousand miles goes out maybe the fluids go good
theoretically but if the transmission isn’t shifting and you got to spend four
or five grand for a new one or have it rebuilt not a good idea
my old Celica it’s got two hundred thirty thousand miles and the
transformation still shifts like a dream mind you I change the fluid every 30,000
miles not that big of a deal I don’t even worry about the filter and that’s
because these toyota designs a lot of them don’t have an actual filter they
got a little screen just like a mosquito screen on the windows of your house you
just clean them you don’t have to replace them because there’s not that
much animal because realize transmission fluid is cheap transmission rebuilds and
new transmissions are very expensive you don’t want it to go this far you don’t
want a transmission that Revs way too high before it starts shifting gears
that’s a no-no you don’t want to transmission that herky-jerky when
it’s taken off or slips when you’re trying to take off and you don’t want to
transmission that you put it in reverse and you step on a gas and it won’t move
anywhere these are all signs that you have a transmission problem you want to
avoid this at all costs let’s say you let it get really dirty never changed it
at all then if you try to flush it all that crud is thrown through the systems
as I said theoretically it sounds like a good idea you’ll flush all the crud out
of the system and have brand new fluid in but it often doesn’t work that way
not only because stuff can get clogged up but an old transmission that’s worn
they are run by friction the fluid has friction in it and the fluid friction
helps the dynamics of making the car move down a road guess what really dirty
fluid actually has more friction in it so if you change your transmission fluid by
flushing it and you get all the dirty friction fluid out put a new slippery
shiny brand-new fluid guess what a lot of times the transmissions will start to
slip now to counteract that on it really all transmission let’s say the
transmission needed a shift solenoid and had to drop the pan real pro mechanics
like myself they will save the old fluid and put it back in so it won’t have that
problem now that might sound like a stupid idea
check out the old fluid replace broken parts then put that old fluid back in
got a car that’s got 150 200 thousand miles a lot of times that is the smarter
way to go with that kind of mileage you’re off and living on borrowed time
and your borrowed time and it goes way down to nothing if you put in fresh fluid from
really all dirty fluid so why does some mechanics and shops tell you oh we’re
gonna flush your transmission fluid well there’s two main reasons for that and
numero uno is it’s a profit-making thing it’s like guys that say oh we have to
power flush your injection system if your car’s running perfectly finding out
no problems a lot of times that’s just over selling something to people and
flushing the transmission fluid it’s an often oversold item and number two it’s
very easy for a shop to do it that has the equipment you’re gonna change the
filter and fluid you got to drop the pan a lot of the modern transmission pans
don’t even have gaskets they’re glued on and let me tell you it is a job getting
that all glue off without breaking anything you gotta hit and pry and pull
it’s messy you gotta buy a filter then you got to fill it all back up but with
the pressure machine automatic transmissions have cooler lines on that
go to the radiator or to a special cooler all I gotta do is take those two
lines off hook it to their machine and flush it through it’s a very easy thing
for them to do with the equipment and as most guys charge more money to flush a
transformation then it just drop the pan and change it they’re making more money
not a good idea to have an automatic transmission flushed now yes you want to
have clean fluid but if you change it off and that’s good enough yeah you’re
not changing at all you’re changing some of it but you’re changing it off that if
you keep doing it and if it has a filter and you change that filter it’s gonna
get rid of any problems that you’re gonna have in the first place and that’s
especially true in modern cars because the new cars most of them use a full
synthetic fluid that fluid lasts longer if you’re just changing a bit at a time
maybe a third at what’s in it when you just change the filter and fluid the old
fluid mixed with the new fluid it doesn’t have the degradation that the fluids did
when I was a young mechanic in the 60s and they just flat wore up plus the
transmissions are so much better made than they used to be back in a day
almost all the American automatic transmissions they had automatic
clutches inside that’s why we called them automatic transmissions and they
would shed a lot of clutch material and that clutch material made of asbestos of
course it’s gonna clog stuff up well they don’t make them like that anymore
so you don’t have to worry about the gross contamination that the older ones
are getting if you didn’t change them a lot you’re gonna have serious problems
but today no the designs are better the fluids are better so you should stay
away from watching them now as far as I’m concerned there’s only one exception
to this rule of not flushing let’s say you got a vehicle and it won’t even go
down the road or it slips so bad then it’s almost un-drivable
what the heck if you want to take a gamble somebody hooking up a machine and getting all the crud out of the system especially an American automatic
transmission you might give it a try if you say that hey it’s gonna cost you
three four grand to have a rebuilt transmission put in and it’s an old car
that’s all worn out and it’s slipping like mad or doesn’t even move what the
heck you might give it a try just to see if it’ll work and sometimes it will
work I’ll say 25-30 percent of the times that I’ve seen it happen like that
they went back to at least drivability they could go down the road okay maybe
they still slipped a little or they clunk a little but you could actually
drive it one before the flush you couldn’t but that’s an extreme case of
an extreme junker worn-out vehicle don’t think that if you got a modern vehicle
that’s got 60 70 thousand miles and it’s a poor design and transmission slipping
or shifting weird that flushing is going to help that at all because realize that
automatic transmissions are very complicated and very sensitive to fluids
differential pressure to the friction that’s inside them it’s not like engine
oil okay you’re driving a car your engines firing gasoline explosions
there’s all kinds of after-effects of the burning and water vapor that get
into the oil and contaminated so that’s just got to be changed at least once a
year or every five six thousand miles in most cases and yes modern automatic
transmissions they’re sealed units get on that explosions and water and stuff
going inside them they are sealed as long you don’t go under water and air
from the transmission bubbles out water takes its place when it’s underwater
because there isn’t the build-up like there isn’t an engine but over time you
don’t get some build-up just from friction things wearing pieces coming
off inside so you do want to change the fluid cloud maybe every 60,000 miles or
something in a modern car but please listen to scotty don’t get suckered into
being sold a transmission flush job because then you ain’t need a
transmission overhaul job shortly after that you just weren’t prepared for
especially if you had a transmission that shifted perfectly fine in the first
place and then it’s starting to act up after the fluid,
so here the key to having a happy smooth running transmission is keep it clean by
regular oil and filter changing but not by the radical process of flushing it
with a power machine, so if you never want to miss another one of my new car
repair videos, remember to ring that Bell

About the Author: Michael Flood


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  2. So what I understand is that if you wanna do it. Do it regularly after every 60k and by the old method of opening the tray and all.
    Now I imported a used car from Japan to Pakistan having 100,000 km on it. The user manual and stuff was in Japanese that I can't understand. How would I really know if the owner had changed it on time or does the oil needs to be changed. Some mechanics here smell the oil and say no need to change.

  3. Dang…that’s exactly what I did on my Envoy was change those 2 shift solenoids and out in fresh fluid instead of the old fluid. Now I’m getting shifting and take off problems..

  4. My 1996 Mazda Protege has 118,000 miles on it and I've changed the filter and fluid twice. I purchased it when it had 68,000 miles and I didn't know if it had service done to it by the previous owner. I changed it soon after I got it and everything looked fine back then. When I changed it 9,000 miles ago the fluid and filter were still clean so I probably won't be doing it again until it reaches 150,000 miles or so. I would never flush a transmission. Whoever came up with that dumb idea is probably laughing his a** off while sitting on the pile of money he made.

  5. Flushed mine because I bought it with dirty fluid and it shifted poorly at 145k. Drives much than before And as the weeks have gone by it is shifting even smoother than the initial better shifting. 4 weeks later I am so glad I did flush. Did it at the dealer that sells them, I dont trust garage mechanics in my area.

  6. I'll admit! In hindsight I wish I would put the old fluid in a transmission I service, had to replace a lockup solenoid in a Chevy 4l60e. Common 3-4 clutch pack wearing!

    Replaced the solenoid and installed new fluid and filter [was a NO NO], immediately driving the 3/4 began to slip! Day later… Transmission wouldn't engage in 3rd.

    High millage Common transmission with clutch problems need to be considered before flushing or fluid/filter changing.

  7. Flush: hook up machine that pushes new stuff in and old stuff out.

    Drop and drain: drop pan and drain, replace filter, refill.

  8. Don't buy cars with automatic transmissions if you want reliability. I have a manual 5 speed with 300,000 miles on it. Works perfect.

  9. I'm ahead of the game. I had my automatic transmission fluid done at 35,000 miles. Refilled with 5 quarts after the pan was dropped. Brand name fluid of course.👍

  10. My Dad's Mechanic Shop is a major failure almost every mechanic that we have had working with us has quit or gotten fired…. owning a mechanic shop next to 20 other mechanic shops it's a stupidest thing you could ever do … My father is not a smart man.

  11. When you do your own oil changes, Scotty, do you put the little sticker in the window stating when the next change is due? LOL

  12. What happens when I drive and the transmission shifts and it makes a jerking feel/sound to it? Dodge Charger. After awhile, it stops doing it.

  13. My Chevy's owner's manual says to replace the automatic transmission fluid ever 45,000 miles. It doesn't say "flush" or "drop the pan", just replace. It's the dealership, so I don't know what they do in back of the shop where mere owners aren't allowed to venture. But they say they use the machine that flushes it.

  14. Any one remember when torque converters had drain plugs? Usually behind the inspection plate and you had to center bottom said plug with the starter…Too bad modern cars don't have that asset

  15. Scotty, I have a 2003 Toyota 4Runner V8 with 104k miles. I’ve babied it. Looks and runs new. Except now. My transmission has started to feel different during shifts, and delays slightly when engaging Drive. Yes, I had my transmission fluid flushed about a year ago – by the Toyota dealer, who recommended I do that. Boy Inwidh I had started watching your videos back then. What can I do before all hell breaks loose? I love my 4 runner, and the new ones can’t compare to the power and solid build of my 2003. Please help.

  16. Hi Scotty, I just bought Rav4 2019 in Canada. At how many Kms do I need to change my Transmission Fluid and after that do I just need to change it or do the flush? Thank You.

  17. I use my van for work. I changed the fluid every 30k miles. the trans failed at 160k. did I do it wrong. 2015 ford t350

  18. Thanks for putting this out there, Scotty. I am also against transmission flushes for the same reason. Just had my pan dropped last month at 30k miles – pan cleaned (including magnets), changed filter and replaced 6.5 qts. out of the 13 qts. that my transmission will hold. Plan on doing another at 60k. Screw Ford and their 150k mike recommendation.

  19. So Ive got a transmission from a junker to put in my truck. I don't know the history. all I know is it works fine. Would you just run it as is or drop the pan and change the filter? If so for dropping the pan, should I recover the old fluid or is it OK to mix new fluid with the old stuff that didn't come out with the pan?

  20. So does the process change if you have a manual transmission? I've heard that it should be done every 60k miles/100k kilometers. From what I understand they use primarily a splash lubrication system but I could be wrong.

  21. I have a 2013 f150 5.0 6 speed auto, trans fluid has never been changed in it that I can find record of. It shifts smooth as can be. I'm afraid to even mess with an oil change cause it already has 178,000 miles on it 🤣🤣🤣 if I get 250,000 and it goes out I'd say it did a hell of a job with no oil change!

  22. What about an ATF fluid exchange (transfusion) machine – not a power flush? The machine also hooks to the cooler hoses. The machine is passive, it uses the transmission pump to pull in new fluid from a reservoir (not under pressure) into the intake hose and expel the old fluid from the output hose. The machine has a computer that exchanges old fluid for new on a 1:1 ratio.

  23. I have a 2011 Nissan Cube. I notice lately when its cold, my transmission doesn’t work. i push the accelerator in park, but the engine doesn’t rev up. When it’s warm, no issues. can cold affect a CVT transmission?

  24. guys fluids such as tranny or engine oil never actually gets worn out from say heat and whatnot……..they just eventually gather dirt and burnt hydrocarbons which makes them dirty……..engines dont get anywhere near hot enough to actually wear the oils out……so thats why there are no lifetime fluids in reality because no engine is perfectly sealed so no dirt can get in or perfectly sealed around all the pistons to where no blow by get by the piston and into the oil

  25. I just do a drain-and-fill every 2 years, or 30,000 miles with AMSOIL Signature Series ATF. I don't clean the pan or the screen.

  26. I have a 2018 Camry SE that has a very jerky transmission, especially on cold starts first thing in the morning/day. I've tried bringing it to 3 different Toyota dealership and they all say it's 'normal'. 1 actually semi-acknowledge the problem and did a reset of the computer but it didn't resolve the issue at all. Not sure if it's just the new 8-speed or what the hell's wrong with it. Anybody else know about this?

  27. Yup that’s why I never flush and when I did it’s cuz that’s all our shop had but now that’s I’m at a dealer we drain and fill and do the filter changes we don’t flush so if a dealer won’t flush why should over shops

  28. OK I'm convinced. Don't power flush the transmission in general. How about a 2010 Crown Victoria police interceptor. Is this still considered a modern car? Do you suppose they did power flashes all through its fleet life with the police department Achoo? And would you say I should just not do a power flush for the remainder of its life? It has 140 K right now. I got it at 138KI drive 1000 miles a year.

  29. I got mine flushed about 8 months ago. about 7k miles driven since. am I in the clear or should I start saving my money for a new trans?

  30. Like your informative videos. As a 2019 Honda Accord Sport 1.5T owner, what do you think of these CVT transmissions; I’m told Honda makes the world’s best CVT; it works fine, but I was just a bit curious as to the life span of these units? (I’m already considering upgrading to the 2.0T engine with the 10 spd auto transmission)
    Keep up the great videos! 👍

  31. hey scotty, i appreciate all your videos. I watch most just for understanding more and knowledge, i'm not even looking for specific things most of the time, you're super funny, you have the right knowledge and actually care about helping others.

  32. I always flush every 40-60 by using the pump in the transmission. It’s already pumping through thru the system just get a hose, bucket and a second person.

  33. What do you suggest doing with a Lexus RX 350 transmission. I asked the dealership to change the fluid and they said there was no need to do it. It's 2013 with only 30K miles on it

  34. Hi Scotty I just purchased a 2008 Volvo S60 2.5T with 73,000 miles and a 2012 Volvo XC90 AWD with 122,000 miles both are paid off cash with the idea of saving money and running both of these cars 200 -300,000 miles before I replace them again. I just watched this video and I’d like to know do you recommend having their transmissions cleaned and filters and fluids replaced? Also, what other maintenance recommendations do you have for these vehicles? I’m in south Florida, otherwise I’d bring them to you. Thank you.

  35. Scott are respected you have a lot of good points but let me tell youabout 19 quarts come out so something was wrong that means there was automatic transmission fluid in radiator fluid running it together which it saves me cuz I bought a red and it saved my problem I would have eventually

  36. I got a 1st gear that slips. I just give it a good rev. When the rpms drop it jerks into gear. It's been my work around for 55,000 miles 😆

  37. Scotty…..completely would flush my jeeps tranny every 30,000 miles. Had it since new. Still have it. 260,000 orig. engine and trans.

  38. See, this is a toss of a coin on a V6 Honda Accord. B7XA transmissions have this counterintuitive modular trans filter that's inside the trans body… And a well documented TSB about failures due to such. Mine started slipping and only has 3rd and reverse now.

  39. So the Ford dealership "Quick Lane" told me they only flush the transmissions, they don't drop the pan. I did have them do it on my 2015 Expedition, and so far I don't have any issues. Not sure where to go to get the drop the pan service, maybe the service side of the dealership would do it instead of the Quick Lane.

  40. You sound like Donald Trump trying to speak on politics when you talk about cars. You know inside the engine you have all sorts of explosions bing boom bang!

  41. I have to say I'm a little confused here. Because first he says to always change the fluid every 60,000 miles in any car, but then says not to because the dirty fluid keeps it from slipping.

  42. I feel like Scotty has made this video many times before. Good thing he keeps making it because people keep making this mistake.

  43. What about a manual transmission how often should I check my gear oil in it I have a 95 f150 with the 300 inline 6 In it the truck has 307k miles the clutch was changed at 150k gear oil was changed at the same time and has never been looked at since then but I have no problams with it ether

  44. Hi Scotty,
    I have a 1985 Toyota pickup 2wd.
    I got stuck in my yard in the mud and now it makes a whining noise underneath by transmission.
    What you think?

  45. Glad your rule doesn't seem to apply to manual transmission. The CRX i bought from ebay had manual transmission fluid that was as black as midnight – it was probably never ever changed for the 257000 miles it was driven.

  46. ZF Lifegaurd 6 fluid is $65 per litre. . . . 🙄 Ford flushed my ZF 6HP26 @ 135 000 klm and charged $438 dollars and they used standard red fully syn multifluid. Transmission now stuffed @ 161 000 klm. Local rebuild quote's are $5000-$8000. Having a rebuild done interstate with clutches that will run on Dextron 6 @$11 per litre. Moving forward plan is to change the fluid and filter every 30 000 klm my self.

  47. I see lots of cheap cars on facebook that say bad transmission. Can't you just hang the transmission from a tree and take it apart and clean it, then put it back together as new? Maybe replace some parts too. I got a set of screw drivers and some rope.

  48. When i took the Auto Mechanics program at vo tech in the mid to late 1990s, my instructor taught that: change transmission fluid and filter as per owners manual specifications. If in doubt then it should be done every 50k miles. If the fluid has more than that, drop pan, replace filter, and save old fluid. Take and run old fluid thru a screen, and pour back in. If you are a bit low after fluid check then top off with new fluid and you are good. I've done this over 20+ years now with 100% good results. The reason behind this is: ATF has very strong detergents in it. All new ATF will wipe out the friction material on the old bands and clutches.

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