What's a Tranny Mount?
A tranny mount (abbreviation for
transmission mount), is an integral part of the suspension which
isolates the harshness and vibration from the road when you drive
your car. To understand the technicalities of the tranny
mount, there are a few items that should covered.
Vibration Absorber
First and foremost, the purpose of a
tranny mount is to isolate vibration from the interior
cabin. Without it, your interior cabin noise will
increase to the point where it would be uncomfortable to drive any
distance longer than down to the local 7-11.
Deflection Fighter
The tranny mount is also used to
combat transmission "movement" during driving. Since
the transmission is connected to the back of the engine, it is the
engine which is doing the twisting when one accelerates or decelerates
(engine braking). Since the engine has it's own mounts (motor
mounts), the transmission also has it's own. Whereas some
movement is expected, too much movement will cause the transmission
to become misaligned with the interior of the car. When the
transmission is not in the same position, it may lead "mis-shifting"
(shifting into the incorrect gear). Generally, a mis-shift
causes an engine to over-rev and cause extensive internal
damage. Especially in an E36 M3, it generally means a few
thousand dollars in repairs.
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typical rubber mount squish
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mount
with Transmission Mount Enforcer
cup
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The Ideal Mount
The ideal tranny
mount will both absorb vibration as the factory intended as well as
minimize the amount of transmission movement during spirited
driving. By firming up the tranny mounts, you're gear shifts
will become more precise than when you car was new from the factory.
Our bushings even incorporate the small notch required for
certain models including E46 330i/Ci 6-speed.
Hundreds of
drivers from daily driven cars to full blown race cars have gained
the benefit of the TME with near elimination transmission
movement. Speedvision teams such as TC Kline, Turner
Motorsport, and ERT to name a few, have all benefited from the TME.
Are you next?
Option
1 - street cars and street cars that see track use:
Black neoprene
transmission mount bushings. These offer excellent drivetrain motion
control Available with or without transmission mount enforcer cups
(combination of bushings and enforcer cups strongly recommended for
E36 M3).
Black neoprene transmission mount bushings shown with optional
enforcer cups.
Option
2 - street cars that see heavy track use, dedicated track
cars:
Red urethane isolated transmission
mount bushings, which are replacing our previous-style red
neoprene. These are fully isolated, having two seperate mounting
bolt hardware pieces embedded in the material just like the black
neoprene and OE BMW bushings. The urethane is a higher durometer
(stiffer) material than the neoprene and offers nearly the same
drivetrain motion control as a solid delrin or aluminum mount, but
with significant vibration isolation. That last detail makes it a
better choice for a track car that is occassionally street-driven,
where cabin noise is a concern. While UUC does expect some
vibration transmitted into the cabin, initial user reports say that
it is minimal and certainly acceptable.. Transmission mount
enforcer cups not required.
Option
3 - dedicated track, road race, and drag race cars only:
Red urethane bolt-through transmission
mount bushings are the strongest choice. A single bolt through the
entire piece eliminates any possibility of bushing material failure
even under the most abusive conditions. Offers effectively the same
drivetrain motion control as a solid delrin or aluminum mount, but
with some vibration isolation to reduce vibratory stress on
mechanical components. Cabin vibration significantly lower than
delrin/aluminum solid mounts, but still noticeable. Transmission
mount enforcer cups not required.
Options 2 and 3 should be augmented with matching UUC isolated
urethane engine mounts:
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