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I run the AMSOIL Synchromesh in my 1990 track car and it holds up great. I get smooth engagement on every shift, including the occasional no lift shift. The fluid comes out clean with no visible metal deposits or signs of the transmission wearing too quickly.
I changed the oil in my '90 ZF after 23 years and 50K miles. It was performing "like new" when I asked my chevy dealer to flush and refill. The cost was $200 for GM synchromesh manual oil. It continues to shift like new with no anomalies.
Since new it has growled in first gear which Chevy told me was normal. You learn to love it talking to you
There's apparently truth to this considering feedback from users of the "recommended" MTF or even lightweight shockproof fluids by Redline. From what I've read over the years, it's about split equally between MTF and the lightweight fluids they sell. Redline would recommend the MTF -- if you called them. Ironically, the lightweight is closer to original stock GM (ZF) fluid viscosity.
I recently came across another post from a member who had horrible gear rattle from their ZF box. They called Redline and they recommended a thicker GL4 which the poster said substantially quieted their box. I'd be hesitant to go too thick on gear oils, some say they get spongy shifts from the thicker oil making a pad between the synchros and the cone of the gear. It really becomes the Goldilocks conversation about what is thick enough to protect but thin enough to get out of the way. On the bright side, my ZF seems to have self healed a needle bearing; i've been sweating bullets the past few days thinking about that potential rebuild bill
07-10-2018, 12:39 PM
