Allison 2000 for AT545 swap

[dave diamond]

A couple of folks have asked so:
Following up on an old thread i have my trans working well now.
took it for a short 100 mile round trip the other day and i think it
is going to be everything i wanted it to be. My main concern was
reducing noise ( my cummins is in the front) it has done that very
well. the engine noise at 65 mph (about 1800 rpm versus previous
2500) is no longer an irritation for me. My next most important
objective was to get a stronger transmission that would handle more
than the 240HP that the at545 is rated for, the 2000 is rated for
300HP. In addition, it looks like my fuel mileage will be at least
10% better, i think i can get 15% increase with a little more
tweaking and a little more experience. i know that the locking
torque converter will give me better engine braking for mountains but
don't know how much better until i get a chance to take a trip
there. I love the way my bus shifts and drives now. very glad i did
this and i highly recommend it.

the mechanical part of the installation was very simple. the 2000 is
only . 75 inch longer than the at 540 series so most likely you will
have enough travel in your slip joint to accomodate it. i have a 3
piece drive shaft with 2 carrier bearings. the carrier bearing
brackets were slotted but i had to lengthen those slots by .75 inch.
I removed the flexplate adapter ring from my at545 and bolted it to
the torque converter of the 2000 and it fit both there and to the
flexplate on the engine with no modification required. Now it was
time to jerk out the old one and bolt in the new one.

my parking brake is on the rear of my transmission. i was able to re-
use it but the fulcrum for the activating lever on the 2000 is built
into the tailshaft at the 3 o,clock position instead of 12 o'clock on
the at540 series. you will need to buy or build some new bracketry.
ordered 2 brackets from bluebird for a total of $28 and was able to
re-use everything else. I also bought a dipstick and tube from blue-
bird ($70)

I built a very simple bracket for my transmission shift cable clamp
out of a short piece of 1.25" square tubing and 1.5" angle. i bolted
that bracket to the 2 frontmost bolts on the pto cover plate. i
bought a clevis from a local hardware store and cut off one side and
put it on the end of the trans shift cable rod and used this to
connect to the existing shift arm on the 2000. This clevis must have
1/4X28 threads (1/4" fine threads)I. had previously tried to just
use the arm off my at545 but found that the connecting hole in the
at545 arm was too far from the fulcrum and kept me from having enough
travel to get both park and 1st gear. I drilled a new hole closer
to the fulcrum but still couldn't get it to adjust correctly, by the
way, if you try to drill the old arm you will have to heat it to
take out the temper before you can drill a hole in it. the 2000 arm
has a shorter throw so less travel is required at the selector to get
all gears selected.

that is about all that is required mechanically for the swap assuming
you buy a used trans that has the correct converter housing. for my
5.9 cummins i needed the sae3 housing and mine came with the sae2
housing even though i was assured twice that it had the sae3. i
bought a used housing and all the gaskets and o-rings i needed from
TKTsales.com for less than $200 and i shopped around until i found an
allison transmission repair specialist that did the labor and checked
their work on a dynamometer for $200. the salvage yard that sold me
the trans agreed to reimburse for changing out the housing, so this
was all at their expense.

Since my trans is a model 2400, it has a parking pawl so i spent an
additional $200 at bluebird on a shift selector with the park
position to take advantage of this feature. My old shift selector
did not have a park position on it.

i contracted with TKTsales.com for a Transmission Control Module with
the appropriate programming and the wiring harnesses for the
transmission and a J1939 data harness to allow engine and
transmission to communicate. Ted at TKTsales also provided loads of
advice (he is an allison dealer). If you have an older non-
electronic engine, you would not need the data harness but you would
probably need to buy a throttle position sensor (about $300) to
communicate with your transmission control module. You will have to
negotiate the price of the control module, programming, wiring
harness, etc. with Ted.

If you have an electronic engine, you will need to get a couple of
parameters changed in the computer for it. In my case, i only
needed to change 2 parameters. Changed top gear ratio from 1.00
to .74 and next gear down to 1.00. I took my ECM off and took it to
a diesel engine shop and they made the parameter changes for $45.
The nearest Cummins dealer said they would charge me a minimum of
$225 to do this.

I paid $1600 for my used transmission delivered and the total cost
of the swap was less than $2800. This was about twice the price of a
differential gear change and much better in my opinion as i still
have my old gears for mountain climbing and i have the overdrive that
will allow me to go 80MPH if i want plus i have a locking torque
converter for better engine braking and i have a trans that is rated
for more power. I also have a very lightly used AT545 with 42K miles
on it that i will eventually sell to recoup some of this
cost. .before i started i asked for quotes on a turnkey swap and was
quoted $12-15K.
dave diamond