Text and Photography by C. Asaravala
It is no
coincidence that AOD spelled backwards is DOA. The Ford
transmission is plagued with slow shifts, poor downshift
response, and an
overall lack of performance. The fact is that if you
want to racing with an automatic transmission, you are
better off with a C4 or even a C6. However the AOD,
being a four speed overdrive, is the only choice for
those wanting to maintain highway cruisability without
having to lift their left foot. So what can be done
to make the AOD more enjoyable? Well, you can go out
an spend $1500 to $3000 on a race prepped, manually
shifted and virtually bulletproof AOD. But who has that
kind of money? The other option is to install a high
performance shift-kit. Shift kits have been around for
a while, and several companies make them. However the
quality of the kits vary tremendously, almost in proportion
to how much work that is involved to install the kit.
The super cheap ones may have you replace a spring or
two, eliminate a check ball here and there, and install
a new separator plate. This will result in hard tire
chirping shifts, but will do nothing for extending the
shift points, or reducing downshift time. Furthermore,
the cheap kits wont make the transmission more durable,
and actually are likely to increase wear. Contrary to
some beliefs, a hard shifting automatic is not always
desirable. Unless the clutches and bands are upgraded
as well, a hard 'banging' shift is going to accelerate
wear of the internal components. That is why it is important
to get a shift kit that offers an upgrade in performance,
as well as increasing durability.
We did our
research on 'do it yourself' AOD shift kits, and found
that TransGo offered the most comprehensive kit to meet
out needs. We wanted a kit that would provide firm,
but not annoyingly harsh, shifts. We also wanted to
extend the shift points in 'D' by 1000 rpm. The stock
AOD, at part throttle, will shift from 1 to 2 at a ridiculously
low 2200-2400 rpm. The 2 to 3 and 3 to OD come just
as quick. We'd like to extend this out to into the powerband
a bit, so the engine isn't bogging a hundred yards off
of a stoplight. We also wanted the ability to hold gears
to any rpm at wide open throttle, as well as downshift,
quickly, at any rpm. The TransGo Performance Shift Kit
(PSK-AOD) offers all of that and more. Gil Younger of
TransGo pioneered the whole idea of "shift kits"
over 35 years ago, and thus they've put a lot of engineering
and research into these kits. Their tag line is "firmness,
control, durability", and we definitely got all
of that with the AOD kit.
They also make kits for the C4, C6, AOD-E and
FMX. Also available are fully manual shifting
for full competition.
The AOD kit runs about $130.
We installed the kit in our 1988 Mustang, using their
video and detailed instructions, and the results exceeded
our expectations. The shifts are firm, and the shift
points have been raised all across the board. At wide
open throttle, in "D", the transmission upshifts
at 4900rpm. Shifting manually, the engine seems to rev
quicker, and the transmission responds immediately to
the gear switch, with an affirmative bark of
the tires. Manual downshifting has improved big time.
Instead of the endless delay between moving the shifter
and waiting for the rpms to climb, now the tach responds
The install takes the better part of a day, so plan
ahead, and more importantly, be patient and meticulous!
Valve bodies are mysterious chunks of aluminum,
full of very tiny parts. Don't lose anything or leave
something out, otherwise your transmission is toast!
Take your time, go over the instructions and video beforehand,
then tackle the job with confidence.