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Ok, thoughts on an aftermarket trans cooler?

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by steved, Apr 8, 2013.

  1. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    I agree synthetic vs conventional fluids is a big difference in cold or warm weather operations I dont know Dextrons temp range I do know at one time in military vehicles it was the only extreme cold weather recommended trans fluid for any mfg vehicle. Not sure if that still holds true.
  2. steved

    steved Former Member

    There are a lot of hydraulic systems that spec ATF if the temps are supposed to get really cold. This truck (read: transmission) won't even break 90*F if its really cold unless your running slow and the converter unlocks a lot. I've noted that it won't lock the converter until the trans reaches about 70*F.

    Isn't Dex6 a thinner synthetic ATF when compared to Dex3? I'm probably going to do a pan drop when the time comes...not really sure what I'll use. I've already had to add to it (mystery fluid disappearance), and used Castrol Dex6. Probably hook up with the local Amsoil guy and see what he can do for me.

    On a side note, I scored a new/unopened 5-gallon pail of Amsoil 75w140 SVO a few weeks back for $50...gotta love Craigslist.
  3. j cat

    j cat Rockstar 3 Years 1000 Posts

    DEXRON VI is a slightly lower viscosity fluid. very close to the toyota transmission fluid they have used for many years. I believe that cold weather with the DEXRON III does cause slippage . with these newer transmissions it is true that if the fluid does not get hot enough you will get the delayed up shifting . with older vehicles that do not have this type control you will not have this effect.

    one thing I did notice with a very large cooler on my 1984 was in the winter the tranny cooler caused the engine to run too cool and I lost some heat out of the heater. I had to block 50% of the radiator to get my toes warmed up in the below 20 deg f temps.

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