Trick Tranny Tips
Words and photos by Steve
transmission builder Steve Oldani specializes
in modifying powerglide transmissions for bracket
racers who want their trans to "hit" the tires
harder in the hope that they will get those
.005 to .007 reaction times necessary in the
ultra-competitive environment of professional
bracket racing. Some of the racers that Oldani
does transmission work for include Super Comp
multi National event winner Paul Pittman and
Super Gas National event winner Carl Root.
Oldani recently modified a powerglide and detailed
what he did to try and improve its performance.
He graciously shared a few of the tricks he
does to his trans, along with some photos. We
thought our readers might find this information
The first change to the transmission was
to replace the 1.76 billet gear set with
a 1.80 straight-cut BTE gear set to effectively
put a lower gear in a car without buying
a new rear gear ratio.
Another major area to improve is the valve
body. The transmission came with a single-passage
transbrake and I modified the case by adding
a second reverse feed hole and a modified
TCI Pro Tree transbrake.
The TCI brake was improved by internal and
external milling, to allow a faster release
time for Pro Tree racing.
In addition to the dual-feed case modifications,
I also added two bleeds for the reverse
circuit, which will allow a more consistent
setting of the brake, because they allow
trapped air to quickly be exhausted from
behind the reverse piston.
One bleed hole is added from the "crescent"
area under the rear cap of the transmission.
Another is drilled through the reverse piston
itself, and it is then installed with the
bleed hole indexed at the 12-o'clock position
in the case. These both have proven to be
major benefits to reaction time and consistency.
low gear servo was added as well. The servo
allows a better seal against the higher
pressures needed to apply the brake.
As preventative maintenance all of the seals,
gaskets, and friction materials inside the transmission
were replaced. The transmission is now ready
for the next race.
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