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Technical Change auto tranny lube? Yes or no?

Discussion in 'The Hokey Ass Message Board' started by Greasyman, Mar 28, 2014.

  1. Greasyman
    Joined: Oct 23, 2010
    Posts: 172

    Greasyman
    Member

    There's a discussion on another car board about changing lube in in auto trannys. It seems there's a lot of talk about trannys going bad after a change. People attribute this to the bands needing the friction material floating around in the old lube to work properly. People also point out that many cars don't have a recommend change interval, the lube is allegedly lifetime. This even goes for older cars, someone said his '65 Vette didn't have a recommended change interval. Personally, I've changed lube on a couple of 904 Torqueflites I've owned and never had a problem. What's the word on this?
     
  2. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,792

    tfeverfred
    Member

    Memory makes me want to say that the change interval, for a TH350, was 30,000 miles. I'm probably WAY wrong, but it makes sense. Barring problems, it's basically fool proof. I check the level, color and smell in mine. If anything seems wrong, I change it. Transmission fluid doesn't see, or at least it shouldn't, all the hi-temps like engine oil does.

    As far as changing fluid & filter too much? I doubt that would be an issue. But stranger things have happened.
     
  3. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,492

    Rusty O'Toole
    Member

    Usually the only time people change trans fluid is when the trans is acting up. Sometimes it cures the trans, great. Other times it doesn't and they blame the fluid change. Ya right, it wasn't the 200,000 miles you drove with the old fluid, it was the new fluid that did the damage.

    Another problem is, that some transmissions are very finicky about their fluid. Certain Chrysler automatics MUST have the correct 7176 trans fluid. Some say you can substitute Dexron, you can't. Even though it says so on the dip stick and in the owner's manual.
     
  4. Pscott
    Joined: Jul 10, 2008
    Posts: 244

    Pscott
    Member

    If this were true, wouldn't the factory fill new trannys wth USED TRANS FLUID?
     

  5. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 8,718

    mgtstumpy
    Member

    Normal transmission range is between 180F- 250F with pan temperature @ 60mph being 180F. Any more that 20mins @300F and you could need some repairs. When towing a load the temperature can easily rise to 250F.

    Cruising at 60mph the pan temp could be 180F and then you pull a slight grade the temp will go to 200F+. Pull a long steep grade or tow and it could climb to 250F. If temperature climbs to 300F over a prolonged period serious damage could occur. Temperature fluctuation is normal however prolonged high temps will definitely shorten the life expectancy of your trans.

    Good fluid is pink, red is used and brown means you've waited too long. For optimum performance change the fluid, purge the system and change the filter every 15k miles (24k klms). For longevity used a quality trans cooler.
     
  6. tfeverfred
    Joined: Nov 11, 2006
    Posts: 15,792

    tfeverfred
    Member

    Well played.

    But I've read where engine oil, with about 1,000 miles on it, is working at it's peak. Could trans fluid be the same way? The more miles on it, the better?
     
  7. aaggie
    Joined: Nov 21, 2009
    Posts: 2,531

    aaggie
    ALLIANCE MEMBER

    I believe in maintaining my vehicles and the ones with automatic trans get fluid and filter changes at 40K. I have had three pickup trucks with over 300K miles and never had any problems.

    My current daily driver is a 2005 GMC Canyon with the 3.5 Liter five cylinder engine and 4L60 trans. At 12K, when I felt the rings were seated, I switched over to 5W-30 Mobil 1 oil and serviced the trans with Mobil synthetic trans fluid. The current odometer is 235997 and it is as strong as the day I bought it.

    It may cost a few dollars but it is far cheaper than a long tow or rebuilding a burned up trans.
     
  8. plym49
    Joined: Aug 9, 2008
    Posts: 2,797

    plym49
    Member
    from Earth

    I know someone who runs a limo company. I once asked about this. He said they regularly change engine oil and never changed trans fluid.
     
  9. oldolds
    Joined: Oct 18, 2010
    Posts: 3,140

    oldolds
    Member

    The guy who rebuilds my everyday driver type transmissions tells me that if it was changed on regular service intervals, keep changing it. If it was never changed ank has 159k on it leave it go, it now needs all that dirt in there to work. He is 70 years old and has been doing tranmissions about as long as I have been alive!
     
  10. Greasyman
    Joined: Oct 23, 2010
    Posts: 172

    Greasyman
    Member

    Ha!, that's what I asked. I said, what do they put in there at the factory, fluid from old taxi cabs? Someone said that the new trannies don't need the friction material in the fluid because there's plenty on the bands, but I don't know if I'm buying that.
     
  11. oldsjoe
    Joined: May 2, 2011
    Posts: 2,536

    oldsjoe
    Member

    I have heard that old wives tale about, if you wait too long then don't change it! I have to call BS! My Dad bought a BRAND NEW Oldsmobile in 1967 it was our one and only daily driver for over 5 years. Dad drove it to work and job sites all over the place, oil changes were done religiously mostly by Dad sometimes by the Shell station he frequented close to work. Routine maintenance was all preformed by Dad tune ups anti freeze changes brake replacement etc. But the transmission fluid was never changed at the owners manual recommendation so Dad also hearing this old wives tale never changed it or had it changed. transmission works flawlessly to this day. But when I inherited the car after Dads passing it had been sitting for over 10 years. i changed all the fluids in the car including the transmission. Like I said it works perfect to this day. So my opinion is if it's dirty change it!
     
  12. Ulu
    Joined: Feb 26, 2014
    Posts: 1,767

    Ulu
    Member
    from CenCal

    I believe the truth is this: new fluid is thinner & pumps easier.

    If a trans is worn, the hydraulic pressure will be a bit low.
    Also the friction bands/clutches will be a bit worn.

    Where the old thick ATF would create enough pressure to make them grab, with new thin fluid they often start to slip right away.

    And leak too.

    This is why mechanics will say to change the oil regularly, BUT don't change it on a high-mileage unit that doesn't slip. Just run it 'til it does, then rebuild it, which makes the most economic sense.
     
  13. For what it's worth, Guys- My OT daily driven Jap car has over 230k on the drivetrain. I looked into changing fluid before vacation, last year. Online and manuals said (there's no drainplug!) drain 3 qts- all you can- at a time and refill w/clean fluid. BUT it must be their brand fluid. Drive a while with that, and do it again. 3 or 4 of these swaps, if I recall was supposed to be the recommended procedure. Kinda Hokey sounding to me, but... so far so good. The Japanese brand dealer fluid was available around town. High as all Hell, but available. Still working fine.

    Actually, of course there is a drainplug- but it only lets about 3 qts. out at a time, if memory serves.
     
    Last edited: Mar 31, 2014
  14. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,455

    Ebbsspeed
    ALLIANCE MEMBER

    The word would be "yes".
     
  15. ahgarageohio
    Joined: Feb 6, 2008
    Posts: 182

    ahgarageohio
    Member
    from ohio

    I just had a trans rebuilt and asked my trans guy this very question. He said if the clutches have any glazing on them and you change the fluid it can wipe them out.
     
  16. elba
    Joined: Feb 9, 2013
    Posts: 624

    elba
    Member

    Change the fluid.. Look at the bottom of the pan of any transmission and you will see small metallic flakes. The flakes are from the flat bearings ( bushings ). Use a paper filter. Do not use the old brass filter. It will fall apart. Install a magnet. I use Type F in 350's and 400's
     
  17. 29AVEE8
    Joined: Jun 28, 2008
    Posts: 1,384

    29AVEE8
    Member

    Change it. If you regularly tow with it, change it twice as often.
     
  18. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,186

    sunbeam
    Member

    I have had problems after changing fluid in high mileage cars. when you change fluid there is a lot of fluid in the convertor that does not get changed. I tend to let sleeping dogs lye.
     
  19. gimpyshotrods
    Joined: May 20, 2009
    Posts: 18,031

    gimpyshotrods
    ALLIANCE MEMBER

    Every 20,000 miles here.
     
  20. indyjps
    Joined: Feb 21, 2007
    Posts: 4,127

    indyjps
    Member

    I've heard it too. Every daily driver of mine has a gm 4L60E and gets changed every 40K, just swap the filter, drain as much as possible and top it off. I had a trailblazer with 80K on it and never changed the fluid, it quit shifting, changed the fluid and all was fine. Made a believer out of me. Every Th350 I've had got frequent changes, most had stall converters so extra heat, change the fluid. The tale may be true on older trans or other makes, the only non gm vehicles I've owned had manual trans.
     
  21. squirrel
    Joined: Sep 23, 2004
    Posts: 48,326

    squirrel
    Member

    I usually end up overhauling the trans in my 55 when it's due for a fluid change...but it leads a hard life.

    My guess is that there are a few transmissions that don't like fluid changes (they're generally old and ready for a rebuild anyway), but most of them don't mind, in fact they might like the fresh fluid to keep the clutches working right, valves moving freely, etc.

    So, don't look for a "one size fits all" answer
     
  22. bigdog
    Joined: Oct 30, 2002
    Posts: 632

    bigdog
    Member

    new fluid is thinner & pumps easier.

    This is just wrong, as oil ages and breaks down the viscosty becomes thinner, not thicker. The only way it could get thicker is if it has so much crap in it that it's making it it thicker. If that's the case you've neglected the maintanance way to long already. Clean is always better then dirty.
     
  23. I agree to change it. I still think the reason people say it causes problems is because people think a trans service will fix a broken transmission. Someone has a trans complaint, gets it serviced then it blows up.


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  24. caton462
    Joined: Jul 17, 2013
    Posts: 176

    caton462
    Member

    About the only issue I have seen with changing very old fluid has to do with the new fluid having good detergent that caused the waxy film that had been stuck to the hot metal parts to flake off and stick a valve in the valve body. The actual oil of the old mineral oil fluids actually holds up very well, the additives, however, seem to die with heat and age. The anti foaming agent is important and when it no longer does it's job you can pump foam through the transmission which will take it out quickly. I usually flush the transmissions that have very old fluid with a solvent that emulsifies the crusty stuff and will run about 2 qts through the system more than it holds to make sure I get all of it out.
     
  25. every 50K for me. OR as soon as I buy another vehicle. Never lost a trans yet in 30 yrs
     
  26. PKap
    Joined: Jan 5, 2011
    Posts: 593

    PKap
    Member
    from Alberta

    I bought my Dad's old chev van as a work truck years ago. He only had it dealer maintained since new, and at 200k when I bought it, the trans fluid in the 700r4 had never been changed (lousy dealer). It was brown, gritty and burnt. My trans shop said that it would need a rebuild for sure, so may as well try to get a few miles on it, as new fluid would likely make it slip like crazy. I put another 190k on it, sold it still running fine at 392,000 on the clock.
    I still change my other ones around 40-50k, but if I get another cooked one, I am going to leave it.


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  27. drptop70ss
    Joined: May 31, 2010
    Posts: 1,172

    drptop70ss
    Member
    from NY

    Only thing I dont agree with is the transmission flushing machines which pumps out everything instead of just dropping the pan and changing the filter.
    I also stick to the rule that if the fluid has been in there for 100K miles and is still nice and red leave it alone. I believe that if the clutches have miles on them the clutch material in the fluid helps to keep them from slipping. Did over 200k on a grand prix automatic before selling it and just about 200K on my GMC truck. IMO if you must change it I would stay the hell away from the tranny flush machines, family member got talked into that with 100K on the car and it was dead in two weeks.
     
  28. Here's how I was taught.

    If you are planning on doing a Trans service- drain with intent of needing to reuse the fluid. That means cleaning the outside of the Trans so no contaminants get into the fluid, using a clean catch pan, and act accordingly. Once the pan is off, examine the pan for friction materials from the clutches, DO NOT clean the pan yet. If there is metal it doesn't matter what you do because it needs a rebuild in the future.

    If there is a significant amount of friction materials in the fluid, 50-75% of the old fluid should be reused and the pan not cleaned of the materials with a new filter installed. This of course is providing the fluid is not burnt or brown and stinky, which means it needs a rebuild. If there's only a small amount of crud then fresh fluid should be used.

    There's theory behind this that's backed by very sound reasoning and plenty of examples that prove it works. Cleaning the pan and fresh fluid in a Trans that shows a significant amount friction materials will almost certainly lead to complete trans failure in short order.
     
  29. tiredford
    Joined: Apr 6, 2009
    Posts: 525

    tiredford
    Member
    from Mo.

    Ha ha, If nobody changed fluid, where would you get used fluid?
     
  30. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,856

    Mike51Merc
    Member

    Yes, and if nobody changed fluid, why would auto parts stores sell the stuff?

    I've got a Ford AOD 4R70W that started to chatter during TC lockup. The symptoms were like driving over rumble strips. I thought I was in for a compete rebuild, or at least a new torque converter. Believe it or not, a fluid change completely fixed it. The old fluid wasn't burned, but it had broken down and lost some of the characteristics from the additives.

    I rebuilt a C4 and learned during the process that the clutch friction materials dictate which fluid to use. Old school friction plates need type F, the newer ones (kevlar) need Dex/Merc fluid. If you put Dex/Merc in an old tranny, you're gonna slip the clutches into oblivion.

    I repaired a CFT30 Ford CVT in a Freestyle/500/Montego. The fluid for that thing costs $12/quart and takes 10 quarts. If you use the wrong stuff or if you contaminate the fluid, the trans will be destroyed in no time.

    The moral of the story is the wrong trans fluid can ruin your day.
     
    Last edited: Mar 30, 2014

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