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GM Synchromesh Trans fluid...thumbs up

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  • GM Synchromesh Trans fluid...thumbs up

    Using this fluid was an old trick I used in my Mustangs to smooth out the gears. I added this to the SS before a road trip this weekend and felt a significant improvement in feel. Noise seemed to lessen as well but it may have been my imagination. $10 a quart from a GM dealer.

    I believe, but not 100% sure, that the Penzoil Synchromesh is the same stuff but can be bought for about $5 a quart from any auto parts store.
    2008 BMW E92 335i 6MT

  • #2
    I use this in my Tib. It's great stuff. Definately a difference in shifting. And it's good for trannies with weak synchros.
    1987 300ZX Turbo - ... php?t=3114
    2001 Tiburon Turbo 60-1 270whp/268tq

    No cupholders? Where am I gonna put my beer????


    • #3
      I don't know if they are from the same mfg or not, but the Penzoil is certainly compatible with the specs. I've heard countless people say to use the syncromesh. It seems to be highly regarded by most tranny shops.

      I have used Redlines stuff and it works quite well. Same results on a T5 and a 30A.


      • #4
        I have tried both and the redline is at least as good as GM's branded synchromesh. Really no difference from the driving perspective... I would buy whichever is easier to find or cheaper, which for me is the redline.


        • #5
          You should at least make sure that the GM stuff is good for GL-4 applications . . .

          I just put some Royal Purple in my 71C. Shifts much better, quiter gears, and second gear works when cold again.
          [strike:ff0tp92h]1984 300ZXT[/strike:ff0tp92h]
          [strike:ff0tp92h]1986 300ZX 2x2 NA2T[/strike:ff0tp92h]
          2000 Porsche Boxster
          2007 Toyota Yaris


          • #6
            I've found that when cold the GM synchromesh is better then the redline. There is redline in my car now. But will switch soon.
            Gone - 1988 Shiro
            2004 BMW 330Ci
            2005 BMW 330i
            1991 Twin Turbo Z's (Red and Black)


            • #7
              bemis wrote: You should at least make sure that the GM stuff is good for GL-4 applications . . .
              True, I've both heard and read that of the GL-5 lubricants will cause premature blocker ring failure if used in our (and many other) manual transmissions.


              • #8
                if I remember.... the gl-5 stuff reacts with the bronze