Throttle Valve Cable Adjustment

[Heath Wade]

I've read several pages about adjusting the TV cable to change shift points.
These pages all extol the benefits but don't mention any possible drawbacks.
I would like to make this change but I don't want to hasten the demise of
this already weak transmission. Can anyone give me some insight into what I
can expect in terms of reduced life expectancy or wear if I make the change?

Thanks,
Heath

[Jerry]

Which transmission and vehicle you talking about?

Jerry

[jetski junkies]

It's not the throttle cable you need to mess with, but the kickdown cable, or
linkage going to the tranny off the accelerator linkage.

Perry

[Gary Glaenzer]

it's a throttle cable, because 727's/ 518's don't use a modulator, the cable
does both, but is called a 'throttle' cable

the only transmission still in use that has a 'kick-down' cable is the old
TH 350; that's all it does, is kick it down at full throttle.

C4's and C6's have a kickdown lever, not a cable.

A4LD's have a throttle cable, AND a modulator, the cable adjusts shift
points, the modulator adjusts line pressure.

TH400's have a modulator only, KD is accomplished by a solenoid that is
operated by a switch on the linkage (or ECM in later models).

NOW......what is this person attempting to DO?

jetski junkies <Perr...@ix.netcom.com> wrote in message
news:3979B0FF...@ix.netcom.com...

[Heath Wade]

Sorry for the lack of info guys. It was late and I was tired. I've got a
98 2WD QC 318 with automatic transmission. I don't like the factory set
shift points. I want to tighten the TV cable (move the cable towards the
firewall) in order to increase the RPMs when the shifts occur. My questions
is how will this affect the life expectancy of the tranny.

Thanks,
Heath
Heath Wade wrote in message <8lbe7i$9c3$1...@slb3.atl.mindspring.net>...

[Gary Glaenzer]

in general, later & firmer shifts (what you want) will make a unit last
longer.....less slipp during shifts.

Heath Wade <heath...@mindspring.com> wrote in message
news:8lcf3p$aqm$1...@slb2.atl.mindspring.net...

[Mean Gene]

Well, if the result is a higher shift point, firmer shifts with less
slippage, and quicker down shifts, the result would be less heat and
clutch wear in the transmission.

My suggestion would be to try adjusting it and watch for any undesirable
results.

The TV cable was mis-adjusted on mine at the factory and the truck
slipped excessively going into third and would not downshift to second
at full throttle even if you slowed to 20 mph before flooring it. I
noticed the mis-adjustment on the test drive and it was adjusted to my
satisfaction before delivery. It will now down shift to second at speeds
in excess of 60 mph. It shifts about 4,900 at full throttle now with
little slippage going into third at full throttle. The convertor locks
at 35 mph in 3rd and goes into OD at 43 mph with light throttle. I have
a 360 w/3.55 gears and 245 tires.

Gene K
Decatur AL
'00 GG300EC
'01 Dodge 1500 CC 2WD

[John Kunkel]

Heath Wade wrote:
>
> I've read several pages about adjusting the TV cable to change shift points.
> These pages all extol the benefits but don't mention any possible drawbacks.
> I would like to make this change but I don't want to hasten the demise of
> this already weak transmission. Can anyone give me some insight into what I
> can expect in terms of reduced life expectancy or wear if I make the change?

The most noticeable effect of changing the TV cable adjustment is the
upshift timing in relation to the throttle setting. If the adjustment is
loosened the trans will upshift early for a given throttle setting.
Conversely, tightening the cable will cause the trans to upshift later.
Other than a "seat of the pants" feeling, there isn't a lot of benefit
of changing the setting.
Loosening the cable for earlier shifts lowers the internal pressures and
can, if taken too far, eventually cause excessive slippage and premature
failure. Tightening the cable for later shifts can cause premature
forced downshifting leading to excessive wear.
John

[360view]

To really get the scoop on the throttle cable adjustment to
control kickdown and line pressure inside a 727/518/46RH/46RE
Torqueflite automatic transmission - go to a Borders Bookstore
and look at the book:

Chrysler Performance Upgrades
by Frank Adkins
ISBN 1-884-089-40-2
published by CarTech in 1999 as item SA-60

The automatic transmission chapter in this book is the best I
have ever read on Torqueflites and has plenty of photos and
simple tables of what tranny parts actuate to make gear changes
happen.

It has a great explanation of how the front clutch and kickdown
band can 'fight each other' during the 'soft shifts' that
Chrysler engineers designed to please grandmothers. It also
explains how the rear 'sprag' can lockup during wheelspin and
then explode when the next gearshift comes 100 yards later.
Adkins even details when and why Chrysler went from the
original "kickdown linkage' to the 'Throttle Valve Cable' you
see on modern Magnum engined trucks. You can read this chapter
for free in 30 minutes at Borders, or buy the whole book for $20.

Adkins explains the pros/cons of tranny wear based on shift
firmness/speed/band adjustment/shift kits/etc.

The throttle cable adjustment that you ask about is a worth
while thing to do if your automatic is shifting at too early in
rpm or if the downshifting is happening at too light a throttle
when it should not. Otherwise do not make the adjustment - it
is not the major factor in tranny wear rate.

If you do decide to experiment with the cable - mark the
original spot on the cable at the clamp with a bit of paint and
let the paint dry. Also measure the distance from the end of the
cable to the clamp and write this down for safekeeping so that
you can go back to the original distance. Marking the cable
with a pen or magic marker doesn't work well and can be rubbed
off. Don't adjust the cable more than one sixteenth of an inch
at a try.

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