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Opinions on synthetic transmission fluid.

Discussion in 'The Garage' started by Derf00, Jul 8, 2003.

  1. Derf00

    Derf00 1/2 ton status

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    I am going to p/u my new 700R4 from Phoenix Transmissions tomorrow. The builder highly recommends using synthetic fluid.

    I am very anxious to see how this transmission performs. All of the local transmission shops either said you can't beef up a 700R4 or they would only rebuild back to factory specs.

    Any opinions about the synthetic fluid would be appreciated.
     
  2. yunit

    yunit 1/2 ton status

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    My rebuilder told me to use synthetic and recommended Redline or a good Dexron III, so I got a Castrol Dexron III synthetic. I even put the Castrol in the 700r4, in my 92 blazer and she runs real nice.
     
  3. 88Silverado

    88Silverado 1/2 ton status

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    The synthetics can take a higher temperature than the standard type. Thats about it. I know of several shops that recommend NOT using synthetic because they have seen some differences in shifting quality between the two and the big cost difference.

    The big thing that kills transmissions is improper maintenance. How many people do you actually know that service their transmissions or even check their fluid to see if its low or looks/smells burned. You should service it (filter change) every 15000-30000 miles (remember, this only adds 3 quarts of fresh fluid. Theres still 8-9 quarts of old fluid still left in the converter and such) and once a year flush the complete system out (including converter).

    I ran synethics for years, now I buy the cheap stuff or whats on sale (lately its been a case of Chevron ATF at Costco for $11.50) and service it often. That basically works out to 1 case per year for standard filter maint and one case a year for a full 12 quart system flush. Thats about $35/yr including filters for a well maintained tranny. Thats pretty cheap.

    I would recommend installing a magnetic filter in the return line of a new tranny for the first 1000 miles or so to catch any left over metal and breakin debris.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah I'd have to agree, standard fluid lasts 100K plus when people don't maintain their rigs, I'd guess synthetic ATF is at least double the cost of standard stuff, meaning you could change it at 50K miles and still come out as good as with synthetic.

    Of course, it likely has better lubricating properties than standard, and reduces power loss some miniscule amount, but I doubt it's worth it. JMO
     
  5. mastercraftkpk

    mastercraftkpk 1/2 ton status

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    If you are going to run the risk of getting water in your tranny, the synthetic fluid may be a god idea.

    Although it is more $$$ for synthetic, it may save you from cooking a tranny w/ H2O.

    Whatever your going to do, slap a good tranny cooler on your unit. Heat kills trannies.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif
     

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