The many causes and confusions regarding Tremec gear rollover noise are well-chronicled, but what eludes some is how to actually suppress the sound of a rattling five or six-speed.
Luckily, American Powertrain (AP) eats, sleeps, and breathes Tremec transmissions. Their intimate knowledge of how these precision beasts actually work has helped more than a few customers negate the noise of a heavy duty geartrain.
“Fluid choice is often the single biggest improvement you can make. The goal is a fluid with proper friction characteristics and enough viscosity to damp gear oscillation,” says their recent tech blog post.
Appropriate options include Dexron III, Mobil 1 ATF, and, of course, Tremec’s own HP-MTF. The latter is factory-recommended for TKX or Magnum boxes and we at Mopar Connection Magazine would agree after Project Brazen, Editor-in-Chief Kevin Shaw’s TKX-equipped 1969 Dodge Charger, made the switch to HP-MTF last year.
Increasing idle RPM can also quash some clatter. It usually doesn’t take much; a bump of 50 to 100 RPM can be enough to smooth out a chopping cam’s torque pulses, thereby lessening the amount of torsional imbalance going into the gearset. Similarly, a heavy steel flywheel, high-quality harmonic balancer, and proper drivetrain alignment will dampen transmitted vibration too.
“Most rollover noise is harmless, but abnormal sounds should be investigated,” AP cautions. Any grinding, whining, or racket when the clutch pedal is depressed merits much deeper investigation. Those could point to problems way more severe than rollover noise. These Tremecs are tough, but not unbreakable, so lend it your ear.
