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T-5 what gear oil to use?

Discussion in 'The Hokey Ass Message Board' started by felix37, May 24, 2009.

  1. felix37
    Joined: Dec 20, 2008
    Posts: 82


    I have just instaled the t-5 behind my flatty and used the technical info that was posted on the HAMB.The article said that the 86-87 non world class should use straight 70-wt oil,not ATF.My question is where do you find this stuff? I have tried O'reilly's,autozone,GM and I'm currently at the NSRA nationals this weekend and the AMSOIL guy's are here and they don't know of such a thing,they did recomend synchromesh gear oil.can anyone help!! thank's jonathan
  2. I read several T-5 threads, and the general consensus seems to be; run synthetic ATF in all of them.
  3. Wildfire
    Joined: Apr 23, 2006
    Posts: 831


    I just put Dex/Mercon in mine.

    Everything I've read says Dexron III, supposed to be the same as what I used.
  4. ALL World Class T-5 use ATF oil and NOT heavy gear oil or Redline MTL! All NON-World Class T-5 use 70 wt gear oil. We recommend high quality Synthetic oil as it lasts a long time and over a larger operating temperature.

  5. t5stang91
    Joined: Dec 20, 2008
    Posts: 300


    i use royal purple , but i beat the shit out my stuff
  6. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don

    I run an old second hand non WC T5 behind a flatty, I run plain old Dexron ATF. Been beatin the crap out of it for years. Check the level once a year and look underneath for oil spots.
  7. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    The original NWC did call for 70wt gear oil. Later, most of the mfgrs didn't differentiate between WC & NWC when specifying ATF.

    I run synthetic ATF even in my NWC boxes and have done for years. No issues for me so far. Shifts are smoother & easier with the ATF vs the 70wt oil.

    Some folks do report good results with Redline's MTL or GM's synchromesh in the NWC trannys...
  8. Snarl
    Joined: Feb 16, 2007
    Posts: 1,639


    Factory GM shop manuals say ATF regardless of year/application or WC/NWC.

    Synthetic ATF seems to be the preferred oil to use.
  9. 61falcon
    Joined: Jan 1, 2009
    Posts: 772


    i run fords motorcraft mercon V, its a synthetic atf.
  10. bill3337
    Joined: Sep 30, 2007
    Posts: 231


    I tried synthetic in mine, but actually liked the feeling of it better with GM ATF in it, so I drained it and refilled it with Dextron III, although I do use a little additive in it.
  11. The factory sticker on the side of the case of the one I've got says to use Dextron.
  12. George G
    Joined: Jun 28, 2005
    Posts: 1,274

    George G

    I used GM Syncromesh transmission oil.
  13. TBone69
    Joined: Aug 21, 2007
    Posts: 819

    from NJ

    I always ran syntehtic ATF in my 90 LX Mustang. I tired synthetic 70 weight once but it didnt shift as smooth.

    I used to drop the clutch at 5 grand with slicks and never had a problem with the ATF.
  14. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,406

    Flat Ernie
    Tech Editor

    That's a WC T5 - do NOT run 70wt in that one...
  15. gas pumper
    Joined: Aug 13, 2007
    Posts: 2,955

    gas pumper

    I use redline MTL. in my 2 NWC T5's. no problems.

    The Mustang kids I knew ran regular ATF and beat the shit out of them and occasionally lose 3rd gear due to driver enthusiasm, not lubricating problems.

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