Added 1 qrt. 15W40 in TH400.....

Discussion in 'The "Juice Box"' started by 75Riv, Sep 3, 2020.

  1. 75Riv

    75Riv A.K.A. Harry Clamshell

    Here goes: finally getting my 68 Wildcat out of winter storage it needed ATF. Added a quart and started the engine and moved the car for about 100yards. When getting my tools and stuff I found out the quart wasn't ATF but engine oil. :eek::eek::eek: (don't ask). Left the car in storage wondering what my next steps would be.
    Will not be able to get the TH out from under the car at its present location. Emptying only the pan is a possibility.

    Is the oil completely mixed with ATF after starting and driving 30 yards and will they separate after a while?

    Which of the 2 is 'heavier'?

    How much of a residue will be harmful to the transmission?

    Any recommendations?
     
  2. Bens99gtp

    Bens99gtp Well-Known Member

    I would drain the pan, remove cooler line and blow out lines and cooler, refill, then take to shop that can do a transmission flush........and i would have them flush through 24 qts or so.

    These trsnnys are pretty forgiving. I'm sure ckean oil is better for them them than some of the black nasty fluid im slot if them
     
  3. docgsx

    docgsx It's not a GTX

    My trans cooler split inside the radiator tank in my van. My transmission filled up with coolant from the engine while I was driving 70 mph up the highway. I towed it to my friends shop and they flushed it. It took 15 gallons of flushing to get normal looking fluid again. that was a couple of months ago and I have been driving it several thousand miles since then. maybe there is hope for yours…
     
  4. lemmy-67

    lemmy-67 Platinum Level Contributor

    Transmission fluid is basically high-detergent machine oil, but is much thinner than 15W-40 motor oil....probably closer to 0W-20. If it was only in there for a short time, probably no to minimal damage, but definitely drain it & flush a few times.

    Once the engine is started, the stator vanes in the converter mix everything together, so the heavy/light oils have combined & colluded.

    I once did the opposite (put ATF into the crankcase) in order to clean out the gunk & bearing flash after the rods & mains were replaced. Lifters were certainly noisy, but only ran it for a few minutes, then put synthetic engine oil back in.
     
    TexasT likes this.
  5. knucklebusted

    knucklebusted Well-Known Member

    First, I'm not a transmission expert but I know the 400 is one tough transmission. Adding motor oil is certainly better than adding water to it. If it had no issues other than being 1qt low, I'm betting you didn't hurt it.

    The typical turbo 400 holds 6 qts and the converter holds 5 qts if it is all stock with a 13" converter. If you have a smaller converter or a deep pan, adjust accordingly.

    One qt of oil in an 11qt system is only 9%. Based on that, 1qt of 15W-40 mixed with 10qts of 0-20W (speculative) would yield 1.4W22. The motor oil additives would worry me more than the actual weight of the oil but not enough to panic. I'm betting you did no harm to the trans at all with such low run time.

    If it were mine, I'd drain as much as you can get out through the pan and the cooler lines. Then refill with your preferred transmission fluid. You'll probably be able to get at least 6qts out through the pan and the lines, maybe more if you let it drain overnight. Six qts of your original 11 will cut the motor oil contaminant level to less than 5%. From there I would drive it to a shop or another place you could manage to drain it again. Another 6 qt flush would yield only trace amounts of motor oil.
     
  6. Briz

    Briz Founders Club Member

    You should be able to do your own flush in and out of the cooler lines. I have a tool with a long hose that sucks fluids out. [​IMG]
     
    dan zepnick likes this.
  7. BQUICK

    BQUICK Gold Level Contributor

    What I do is disconnect trans outlet line and put a hose on it and have it dump into a 5 gallon jug that you can watch and see level. Start motor and add trans fluid using a gallon jug while watching 5 gallon jug to estimate amount. Do 2 gallons and run around and shut car off.
    Sounds a little crazy but works for me. Takes less time than dropping pan. granted you don't clean out pan or change filter but you do exchange most of the fluid. Actually more than if you drop pan.
     
    GS44667, Briz and buicksWILD like this.
  8. dan zepnick

    dan zepnick Well-Known Member

    We have one of these at work. It works great on oil changes on these cars with lower engine covers.
     
  9. buicksWILD

    buicksWILD Well-Known Member

    That actually sounds brilliant to me.
     
  10. silvergs72

    silvergs72 silvergs

    Yep I used to do that in a Ford high boy truck that I put a BBB and th400 in. I would go wheeling and get in water pretty deep. Trany would take in water and start shifting funky. Stop and pull a trany line off the radiator and get a couple of gallons of trany fluid that I carried with. Start the truck and watch the color of the fluid coming out of the line. Kept pouring in new until the "pink milkshake" turned red again. Put line back on and top it off. I know it happened at least a dozen times over 10 years and the trany never gave me any issues at all. They are tough!!!!
     
    Fox's Den and SpecialWagon65 like this.
  11. 1972Mach1

    1972Mach1 Just some M.M.O.G. guy.....

    I blew the pump seal out of my F250 with a 460/E4OD towing an enclosed trailer 45 miles from home. Smoke billowing out the back, trailer drenched in red fluid looking like a murder scene. All I had in the back of the truck was about 10 gallons of used 15w40 and 20w50 oil I was going to give to my buddy with an oil burner for a furnace in his shop.....Filled the trans with the used engine oil and took off. Made about 15 miles, refilled, and repeated. Pulled the trans after I got home, cleaned everything out, replaced the pump seal, and drove it for another 25,000 miles after that. Trans finally gave out at 180,000 miles on the truck, and now has a reman in it.
     
  12. Matt69olds

    Matt69olds Well-Known Member

    A quart of engine oil in the transmission is better than running it a quart low. However, I would suggest getting the engine oil out. I have no clue what long term effect engine oil would be on transmission seals and parts, but better safe than sorry.

    Remove the lower cooler line at the radiator. Connect a hose to the radiator, and have the other end of the hose in a 5 gallon bucket. Start the engine, and pour in trans fluid as the bucket is filled with the crud flushed out of the trans, converter and cooler. When you see clean red ATF that looks like what your pouring in, stop the engine. Reconnect the cooler line, drop the pan, change the filter, refill, and relax.
     
  13. 75Riv

    75Riv A.K.A. Harry Clamshell

    Should have come back here earlier; thanks for all your informative replies. Was able to drain most of the fluid through cooler line, filled up, drove to a nearby shop, drained again, flushed and poured fresh ATF. Up and running again. Thanks!!!
     
    SpecialWagon65 and knucklebusted like this.
  14. Mart

    Mart Gold level member

    Co worker years ago said disconnect out line from trans at radiator and start engine, let it pour out in 5 gallon pail till it starts to spit air. Shut it down and fill trans back up. Said you get all the fluid out of trans & convertor. Said it doesn't run dry long enough to burn anything up & it works! All the internals still have a film of fluid on everything.

    Just can't remember if he started engine and put trans in drive or left it in park waiting for fluid to run out and start to spit air....
     

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