I have heard this over the years and even experienced it myself. I heard that if you have an auto tranny that you haven't kept serviced at its regular intervals, then leave it alone. Somehow by changing the fluid, you "wash out" all this worn off friction material floating around in the fluid that actually helps the trans operate. Can anyone vouch for this? I didn't believe it when I first heard it so I changed the filter and fluid on a Cruisomatic. It failed a short time later. So I have a Ford AOD that has been sitting outside for years. I think the dipstick may have been left out for a time so I'm worried about what might be in the pan. I think it would be safer to drain it and refill before I start to run it. I suppose its one of those "darned if you do, darned if you don't" scenarios. Are there any procedures for preparing a tranny that hasn't been ran in a long time?
i beilieve it to be true...flushed an old 350 that was never serviced to my knowlege....made it about 50 miles after that...same with a 360 for my amx...did a flush on it and made it to the next house before the ringstarted clackin and finally stuck ...
so true..i dont know how many times a friend will ask if changin the fliud will stop it from slippin.....nope!!
I was just talking about that today. A friend had his 2002 Family car in for service and went along with the recommendation that the fluid be changed. A few weeks later he had to get a shift solenoid pack changed.
I definitely believe its true. Im sure it doesnt happen EVERY time, but it certainly does happen. #1-My dad was going elk hunting in montana and decided to change his tranny and engine oils before the trip. It was a year old chev pickup, about 60k miles on it. On the way there the tranny went out. #2-My moms chrysler sebring, only it went out about 2 weeks after the change. #3-when I was 14 I got my first pickup, 90 chev fullsize shorty stepside. Tranny worked great, changed the atf (just thought it would be a friendly gesture to the pickup ), and that tranny (700r4) went out within 500 miles. #4-my dad bought an elcamino at barrett jackson in FL last year, and the tranny pan gasket was leaking, so he replaced it. Somewhere less than 100 miles later I was driving it and quickly noticed I only had 1st gear. Fried. im definitely a believer.
The trans shop that wants to sell you a fluid change to see if it will help your already burnt trans is stealing from you. The damage is done. I have done fluid changes on 60's Ford trannys to have them die soon after. So the dont change it theory seems to work on them. Keep in mind the fliuds back then were formulated differently from today. Type F fluid is getting hard to find. That being said, when I worked at Acura and Honda dealers, if you had a slipping auto trans, we would flush it out by filling it 3 times and running it through the gears. We used Honda spec fluid. 8 out of 10 times it would satisfactorily fix the problem. Caused by running Dextron 2 instead of Honda fluid. If its been in an idle car, but still full, leave it be. If its open to the weather, you'll need to at least drop the pan to get the dirt and water out. Trans-x is worth a shot. I might get you by for a while.
I work at a GM shop and it has happened to customers. If they have a flush that is the only time I have seen it happen. If we drop the pan and replace the filter (exchanging less fluid) there has not been a problem. The failures have only happened on High mileage trannys that have not been serviced prior.
man i just pulled a turbo 350 outa a guys back yard he knew nothing about but said he woudent run it it had no dip stick tube and sat for 2 years open i puled the pan it was like brand new changed the oil and drove the shit outa it
i have a very good friend who is a national master tech for a major tranny company...we just had this conversation.... the risk of flushing or even changing the fluid ona bum trans is that the dramatic change of viscosity has the tendency to wash the carbon buildup off of the band and clutches causing a bigger slip.... he recommended NOT doing a fluid exchange (flush) except where the car got one at 36k and every 36k...(with regular pan drop and filter at every 12k)... its one of those procedures that needs to be done as part of the regular scheduled maintenence from day one.... thing is that many manufacturers are calling for 60, 75, or 100k mile service intervals on some new vehicle trannys...we have a trailblazer in our fleet with no provision to drain or fill the trans...non-serviceable according to the manual...100k servie interval! in that instance, a flush MAY be ok if the vehicle was driven normally and not abused. the tolerances and materials and lubricants they're using today area far cry from a turbo 350 and typeF!
Changing fluid will NOT hurt a good trans.Changing fluid on a questionable trans may or not help it.Always change filter.I have seen fresh fluid cause a varnished trans to break loose some hard varnish and stick VB .Real world advise ,change fluid before it ever turns brown.Could be every year on a plow truck,50,000 on a light duty auto.
In my opinion...changing the fluid will not hurt the trans...but a complete flush can remove some of the deposits holding the trans together and also the gaskets together for that matter. So...I'm always just changing the fluid in the pan...I've never completely flushed out an old trans while it was still in the car and working fine. My main concern is always to get bad burnt fluid out.
i always flush my trannys,by taking off a cooler line and running the engine while pouring fluid in the dipstick until the fluid is clear,i've done it for years and i did it on a fleet that i maintained for 10 years and never had a failure. all of these cars and trucks had that done every 35,000 miles.none had burnt fluid to start with though, when i was a kid i had a 65 impala witha powerglide,the fluid was black,so i changed it,it would not even move after that,so i drained the fluid out and put in 30wt motor oil,i drove that car 30,000 miles after that.true story! randy
I've heard this tale too but haven't had much experience with it. Funny thing is I just dropped my pan yesterday on a 60k tranny. It was pretty dirty and the magnet was covered in metal goop. I just replaced the fluid I took out and replaced the filter. We'll see how it goes.... worse comes to worse I can get that new tranny I want!
if there is clutch material in the oil, its already done. The added material in the oil, does help stop slippage. When you remove the material, the clutches will just slip, but it doesnt matter...it needed a rebuild anyway. Hopefully that makes sense
Yup, a good friend owns a tranny shop and I called him on this. He said that anytime he flushes a trans on a vehicle with neglect he gets a call back saying the trans failed shortly thereafter. He wont do them anymore because of the customers calling blaming him for the failure. (would you go back to a shop that did routine work on your car and the part they serviced fails right afterwords?)
This one was my friend's wife's car - I don't think she abused it and it didn't seem to slip, just wouldn't shift properly - probably a coincidence in this case.
Well, mine in my driver shifts goofy sometimes (700R4, usually the 1-2 shift is rough), but it leaks so much I don't see any reason to change it unless I put a filter on. When I got it it was so low that when I put it in overdrive it shifted up and down hunting gears until I gave up and left it in drive the rest of the way home. There was just enough fluid on the stick to give the illusion of having plenty in it - I added 3 quarts. I had a trans line let go on me on the road once, too, I had to unplumb the cooler to get by and it lost enough it was starting to slip a little in the 3 or 4 miles it took to find a gas station and get some ATF. Now I carry a gallon with me. It likes every so often when parked with the front higher than the back to make a big puddle right out the tailshaft, I haven't investigated to see if there's a seal there I need to change or what. I pulled a car trailer with a '53 Chevy ragtop 25 miles with it the other day plus drove it about 230 miles on top of that and it's still going. But I am sure sooner or later I will blow it out of there and have to get another. For now I just keep it topped off, and I've put 23,000 miles on it since that day I drove it home, towed trailer, flat towed cars, hauled all kinds of crap in the back - I had a Dodge that was run so low that when it warmed up it would stop moving, once before I got it, and when I got it and was on the way up to the parts store to buy ATF. I did a fluid and filter on it in the driveway and I got about 1200 miles out of it, still going when I sold it to a guy who wanted a parts truck. It too shifted odd, the kickdown lever seemed to be gummed up where it went into the trans, and I got lousy milage, but I guess that's normal for those. I did a F&F on one other car that was suspect, a 200R4 in a Pontiac wagon, I still have the trans - it got a factory reman motor at some point, had 110K on it when I got it, the engine and trans were really clean. Never any trouble there either. But I'd never flush an unknown trans - a filter and a few quarts new, sure, clean the junk out of the pan, and if it works don't mess with it.
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