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.http://www.powertraincontrolsolutions.com/content-4.html

pricey....but it'll solve your problem.

~:~
MarshMonster
~:~

   I'd guess that IF your harness and computer are from a 2001 GM product,
it will have plugs for a 4L60E tranny, unless it is for a bigger truck with
the 4L80E tranny.  I'm betting that the 4L80E has the same fittings/wiring
as the 4L60E trans.  These plugs consist of one 2-wire plug to connect to
left(driver's side) rear of tranny where the VSS is situated(provides
signals for factory speedo & cruise control), and another 4(+?) wire plug
that plugs down onto an upward-facing connector about 2/3 towards the front
of right(passenger) side of tranny, which make up the connectors that tell
the solenoids when to actuate shifting--both up and downshifting.
   Good luck & if you have problems, print out these 4 wiring diagrams(for
the '95 truck)  from like Mitchell 1 On Demand--you'll need the
transmission-, the cruise control-, the PCM-, and the instrument
cluster-diagrams.  If you know what harness "Canada Post" used, it'd be nice
to have those same 4 diagrams for that application.
   At the worst, you may need the '95 truck PCM and harness.     BTW, a
well-built 700R4 trans, same overdrive characteristics,  would be a heck of
a lot easier to wire up--virtually none; just install a $75-100-kit from
Summit which makes that trans shift from vacuum.  HTH & good luck, s

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Answers to yer questions....
Then.....comments to follow...
whether you want them or not.

1)
The computer doesn't know what year the tranny is.........
and the tranny is'nt going to confess it.
2)
Who knows....
I mean....you haven't stated what harness was sent to you.
If it's a 4L80E harness....then yes.
If it's not...then no.
3)
Again.......who knows.
You haven't stated if the computer is for a 4L60E, or a 4L80E.
If it's for a 4L80E..then yes.
If it's for a 4L60E..then no.
4)
I have NEVER, EVER, NEVER...even once..heard of a "soft shifting
clutch".
and...95 to present trannies all have the same amount of solenoids in
them
on each model number.  Be it 4L60E, or 4L80e, or....th125c.
5)
Your original shifter will be fine....if.....you're willing to modify
the linkage
set up.  And note.....I mean fairly extensive modification.
.
.
.
Now.....
some ~Random Thoughts~

this dudes done went and bought a crate eng. with a computer for a
4L60E that IS NOT going to work with a 4L80E tranny...NEVER!!  EVER!!
never,never,never,never,.......ever.
and I don't care what Tom says.

this dudes harness is for a 4L60E.
the above ever,nevers apply.
so does the "Tom says" statement.

this dude ain't got a clue who Tom is.

this dude reeeeeeeeeellly ain't got a clue....or......
he's got deep pockets........
in which case....
he should have bought a 3500 series Parcel truck with the setup he
wanted.
and......he'd be frustration ahead.....and at about the same price.

Tom ain't got a clue either.....that's why he ain't posted yet on this
thread,
cuz......well all know he's read it.......cuz....he's jest that way.

~~End......Random Thoughts~

Suggestions to the OP.......

check out the link I sent you.....it's yer easiest option with the
setup you've got.

 I'm fairly convinced, but you have'nt stated, that the harness and
computer
that were shipped to you are compatible with a 4L60E tranny.

The computer will think it's commanding a 4L60E, which has different
gear
ratios than the 4L80E tranny!!!!!!   Not to mention the fact that the
two units
have different "case" connectors that CAN NOT be interchanged.

You asked about "soft shifting clutches".  The is no such thing.
What you "may" have heard, or "may" be thinking of, of "may" be
associating this terminology with.....is the fact that newer trannies
have what is called....."Pulse Width Modulated" torque convertor
apply.  Now.....you've got a 2001 computer...it's logic "should have"
PWM programming.  I say should......because as I stated earlier, you
have yet to state for fact that the computer is from GM.  I'm jest
a.s U Meing that it is.
   Now.....here's the deal.....that pwm computer isn't..........

fk it.

do a google.

or.......

jest stick the damn 400 back in it and drive the damn thing for what it
is....
a piece of sheet.

sorry so frank.
sorry so cold.
sorry .......but you've done this thing to yerself.

and...
you've either got more money than sense.......
or...
you're too dang ignorant to understand what yer attempting to do.

okay.....
so i lied........
i'm not sorry.

but honestly......
you asked for it.

~:~
MarshMonster
~sips his crownroyal.......and ponders ignorance.....is it reeeely
bliss,
or is it.........well.......jest ignorance~