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Hot Rods transmission fluid

Discussion in 'The Hokey Ass Message Board' started by HOTRODPRIMER, Dec 23, 2017.

  1. I am to the point where I feel like the transmission fluid in the old Deuce beater needs to be changed,I built the car about 22 years ago,it's not slipping but I think it's past time to do some preventive maintenance.

    The question is what's the correct transmission fluid and how many quarts does it take to fill a 350 turbo. HRP
     
  2. KoolKat-57
    Joined: Feb 22, 2010
    Posts: 3,053

    KoolKat-57
    Member
    from Dublin, OH

    If just regular service with filter and gasket change, you would need 4 1/2 qts.
    KK
     
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  3. a complete flush and fill will take 11-12 quarts of Dextron 3
     
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  4. gimpyshotrods
    Joined: May 20, 2009
    Posts: 21,829

    gimpyshotrods
    ALLIANCE MEMBER

    Dexmerc seems to be working fine for me out here. Haven't seen Dexron 3 since forever.
     
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  5. Blues4U
    Joined: Oct 1, 2015
    Posts: 7,043

    Blues4U
    Member
    from So Cal

    Dexron III is actually an obsolete specification, and GM, who owns the Dexron name and issues the licenses will not license any more Dexron III. However, fluids meeting the spec are still available out there, they just have to word things a little differently, they cannot label it as Dexron III, but they'll say something like "can be used where Dexron III is specified".

    Here are a couple from the majors:
    https://www.valvoline.com/our-products/automatic-transmission-products/dex-merc-atf

    http://www.pennzoil.com/en_us/produ...6b2lsLzIwMTZuZXdzbGV0dGVyLz9sb2NhbGU9ZW5fdXM=

    https://www.valvoline.com/our-products/automatic-transmission-products/dex-merc-atf

    https://msdspds.castrol.com/bpglis/...3A1FD148025814500665523/$File/BPXE-ANM933.pdf

    https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=77329&docFormat=PDF

    Even Wallyworld carries a version:
    https://www.walmart.com/ip/Super-Tech-Automatic-Transmission-Fluid/16213433

    Note that Dexron VI is the current specification, and you can use Dexron VI in older applications that originally called for Dexron III, it is backwards compatible. The only downside to using a current Dex VI product that I know of is cost, Dexron VI fluids are full synthetic and cost more than mineral Dexron III fluids.
     
  6. It's an automatic! :eek: Just remove the entire thing and put standard in it's place! :p
     
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  7. the label on the O'Reilly bottle says meets Dextron 3 specifications
     
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  8. gimpyshotrods
    Joined: May 20, 2009
    Posts: 21,829

    gimpyshotrods
    ALLIANCE MEMBER

    Although popular, there is no T in Dexron.
     
  9. i'm sure glad you are on here , i don't know how i'd get anything done correctly
     
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  10. gimpyshotrods
    Joined: May 20, 2009
    Posts: 21,829

    gimpyshotrods
    ALLIANCE MEMBER

    I know, right:eek:
     
  11. BamaMav
    Joined: Jun 19, 2011
    Posts: 6,025

    BamaMav
    Member
    from Berry, AL

    If it hasn't been changed in 20+ years, I wouldn't mess with it now. May be an old wives tale, but I always heard if you didn't service a automatic trans regularly, it was better to just leave the old fluid in there since it was full of friction particles from the clutches. Supposedly when you took all those particles out the clutches wouldn't hold as good, and would burn out quicker. I can't say if it's true or not, but I do know I changed the fluid and filter on a high mileage trans once, and two weeks later it went to slipping, it had been fine for a long while before that. Might have just been a coincidence, or might have been due to changing the fluid, I don't know.
     
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  12. squirrel
    Joined: Sep 23, 2004
    Posts: 52,772

    squirrel
    Member

    If it were an overdrive trans, then maybe I'd consider leaving the fluid alone...but not on an old 3 speed auto like the TH350

    atf.jpeg
     
  13. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,326

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    If the old fluid is full of friction material, ostensibly helping the clutch packs grip, wouldn't that also eat up bushings and bearings? How is it that we think contaminated engine oil needs changing, but not the trans? I say change it.

    Ray
     
  14. jeffd1988
    Joined: Apr 12, 2016
    Posts: 537

    jeffd1988

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  15. BamaMav
    Joined: Jun 19, 2011
    Posts: 6,025

    BamaMav
    Member
    from Berry, AL

    Engine oil gets full of carbon and byproducts from combustion, trans fluid only has wear particles from the trans in it. The friction material probably does eat up the bushings and bearings, but at a lesser rate.
    Like I said in my original post, could be true, could be an old wives tale. Just passing on what I was told years ago, do what you think best.....
     
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  16. Yeah,like I said,outta sight outta mind.

    The automatic transmission's work so well you really don't pay them any attention unless they leak or start slipping,in this case I started thinking just how long ago it was rebuilt. HRP
     
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  17. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 10,773

    Johnny Gee
    Member
    from Downey, Ca

    Should have left the 22 year's out of your post. :p
     
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  18. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,326

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Great endorsement for TH350 and your rebuilder!

    Ray
     
  19. Why,it's the truth. HRP
     
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  20. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 10,773

    Johnny Gee
    Member
    from Downey, Ca

    When broken apart what your really asking here is this. What trans fluid to use because in the last 22 years things have changed. But some didn't see it that way. Truth is, we all see only what we wanna see.
     
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  21. Reading many articles I see where the recommendation suggest between 30,000 and 60,000 miles so I'm just a little over the recommended amount.:D HRP
     
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  22. driverquality
    Joined: Sep 17, 2017
    Posts: 22

    driverquality
    Member

    Ive rebuilt hundreds of automatic transmissions over the years, so have a little insight on this. Everyone’s opinion is different, but mine is change it with the cheapest ATF you can find. A TH350 is not a precision instrument (for example it has a screen instead of a real filter)like some of today’s units, so it’d probably work ok with engine oil if no ATF were available. While I agree the fluid doesn’t get full of carbon like engine oil, it does lose its friction qualities over time. Also, the detergents in the fluid wear out too. The “wives tale” has some truth to it, the slipping most likely happened sooner than it would have if it were left alone, but new fluid didn’t cause the trans to fail. All the new detergents likely “cleaned” all the crud out of the nooks & crannies, allowing it to circulate in the fluid instead of sitting dormant, causing the problem to happen sooner.

    It’s mechanical, so 2 things can be guaranteed:
    1. it WILL fail eventually
    2. proper maintenance will prolong the time before #1 occurs.
    -driverquality
     
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  23. I never believed that changing the fluid caused a transmission to fail,the story behind the tale is the transmission was on it's last leg and slipping and the damage was already done before the clean fluids were added. HRP
     
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  24. Mr48chev
    Joined: Dec 28, 2007
    Posts: 32,120

    Mr48chev
    ALLIANCE MEMBER

    I think that changing fluid might cause one to fail comes about because the majority of guys change fluid and filter when the trans acts up and then it fails not long after when it was to the point of failing anyhow.
    On the amount you put back in. I always put in three or four quarts and then start it and work the shifter through the gears a couple of times and then start checking and finish filling it to the right level. I put a lot of miles on my rigs though but that will change after the first when I retire on the second and don't drive 60 miles every day of the week.
     
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  25. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,321

    slowmotion
    Member

    BINGO!!
    Hold your cards please...:eek::D
     
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  26. Blues4U
    Joined: Oct 1, 2015
    Posts: 7,043

    Blues4U
    Member
    from So Cal

    #1 killer of automatic transmissions is heat, #2 is oxidized trans fluid that starts laying down lacquer and varnish deposits, causing valves and clutch apply pistons to stick and not move smoothly, which leads to slow shifts, which leads to worn plates. Depletion of detergents and dispersants adds to the problem of deposit buildup. Depletion of friction modifiers leads to aggressive wear of the clutch plates.

    The thing is, #1 (heat) drives #2.

    Yeah, it definitely helps to change the stuff out once in awhile, get rid of the nasty stuff and replenish the additives. I like that saying someone posted above, If it's red, save your bread. If it's brown, got to town. The problem is, by the time the fluid is brown it's already pretty nasty, better to change it while still red IMO.
     
  27. Change fluid and filter and she will be happy. Merry Christmas HRP.:)
     
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  28. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    The way I heard it growing up was similar, if it had a lot of miles and/or never been changed, leave it alone, new fluid will just cause trouble.
     
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  29. old sparks
    Joined: Mar 12, 2012
    Posts: 414

    old sparks
    Member

    to much being said. the man is right when he said oil is oil. I used 10 weight hydraulic fluid in a powerglide behind 1800 hp and it worked just fine. you do know they dyno racing engines with mineral oil in them
     
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