Pwr Steering Fluid in Trans

91Toranado_Geek91Toranado_Geek Member Posts: 3
edited July 2021 in Oldsmobile
4T60E Tranny. Hi y'all. I have an oil cooler for my trans and my power steering. in doing major repairs I replaced all the lines. I accidentally crossed 2 lines so the power steering and tranny fluid were circulating together. I didn't know and added 2 1/2 quarts of pwr st. fluid. I've flushed the tranny twice since correcting the lines. will the pwr st. fluid harm the tranny? How many times should I flush it? Using Dexron VI synthetic. Tranny fluid looks ok now, just a little thin. I am going to flush it 1 or 2 more times unless I get different advice here. Thanks for any input.


  • thecardoc3thecardoc3 Member Posts: 5,570
    The power steering fluid has additives that keep the seals softer than what the transmission fluid would and it's viscosity is slightly higher. Other than that the two fluids are very similar (transmission fluid is an acceptable choice for power steering systems in a lot of cars) so if you had to accidently cross contaminate two fluids this oops is likely to be far more forgiving than a lot of others. In thinking about this what you accomplished is pretty close to adding an off the shelf transmission fluid additive, without all of the additives. At this point I would just advise you to run it. If it is going to do any harm you aren't going to prevent it at this point by going through any more fluid.
  • 91Toranado_Geek91Toranado_Geek Member Posts: 3
    Thanks cardoc3, that eases my mind a little. I'm just going to fill it today and see how it runs. This flushing was getting quite expensive! Felt like I was just flushing my money down the drain. :D Ha Ha. Seriously though, each flush cost me about $50, And when it happened I had brand new fluid and filter in it. So I'll know something soon. I'll let you know the outcome.
    Thanks again!
  • 91Toranado_Geek91Toranado_Geek Member Posts: 3
    Update: when this happened it had brand new tranny fluid in it. So in the end I ended up draining that and flushing it twice with new fluid and then I filled it with new fluid and drove it a few miles and the tranny is shifting just fine. After I put more miles on it if it acts up I'll let you know, otherwise all is OK. power steering is doing fine too.
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