frank,
you are right. The Jet chip must change the pulse width modulation of the
governer solenoid. This essentially applies the regulated pressure to the
delivery port for "distribution" to the rest of the transmission. Its like
a chopper regulator in an electronic circuit. it can either be W/O and
deliver full pressure, or modulate the pressure by rapidly opening and
closing, say 0-100% duty cycle. The addtl. 7 lbs is coming from this
solenoid by starting at a higher duty cycle, ie: 30% instead of 0. In
reality, the 7lbs "extra" was always there at the hydraulic pressure
regulator. Its now applied sooner and 100% is also applied "sooner"
(according to Glen provided I didnt slaughter his explaination). If you
increase the regulator pressure, then the Jet chip would give you 7lbs + the
additional Lbs from the adjustment. This, as described by Glen at transgo,
will "confuse" the transmission and could cause it to not upshift into
3rd/4th depending on load and a few other things (it apparently gets
complicated, just look at the hydraulic schematic). He did say that it does
not really damage the trans per se, but will cause you to hit the rev
limiter and not shift (not a good scenario) Jet is right, you are right,
and Transgo appears to be right, at least it doesnt seem to me like anyone
is in disagreement. And this only applies to 44/46 RE transmissions, not
the RH or 3500s, 727s 904s etc...
Bruce
At 11:48 AM 7/31/98 -0700, you wrote:
>I'm gonna try this one more time. Again I must say that transmissions
>are not
>what I would consider my strongest point. I called JET again and they
>assure
>me that they DO control shift pressures and thay actually increase it by
>approx.
>7 psi. If they do, then this should increase shift firmness. I'll check
>the the
>service manuals (outputs from the computer), again tonight.
>
> Frank
>
>> -----Original Message-----
>> From: Holloway,Frank T [SMTP:Frank.T.Holloway@kp.org]
>> Sent: Friday, July 31, 1998 9:11 AM
>> To: 'dakota-truck@buffnet.net'
>> Subject: RE: DML: Shift kit update, need more info obviously
>>
>> Hay Bruce,
>>
>> I may have given you some incorrect information yesterday. JET told me
>> that
>> their chips DO modify shift points and firmness. I had no reason to to
>> disbelieve
>> them. I generally spend my time on engines (and if the trans works,
>> don't mess with
>> it). I spent some time in the service manuals last night, the only
>> thing
>> the computer
>> does in regards to the tranny is the 3rd 4th (overdrive) upshift and
>> downshift and converter
>> lock-up. The computer looks at two items to control these, vehicle
>> speed, and temperature.
>> The above is just a simple activation and de-activation of a a
>> valve.No
>> line pressure change.
>> Normal upshifts and downshifts are controlled by throttle position via
>> a
>> machanical linkage.
>> It is highly unlikely the the modifications performed by JET would
>> indeed make enough difference
>> in throttle position to change shift points.
>>
>> Frank
>>
>> > -----Original Message-----
>> > From: Bruce Bridges [SMTP:bbridges@alarismed.com]
>> > Sent: Friday, July 31, 1998 7:26 AM
>> > To: dakota-truck@buffnet.net
>> > Subject: Re: DML: Shift kit update, need more info obviously
>> >
>> > gene,
>> > what mechanisim is used to modify the line pressure via computer?
>> Ive
>> > checked the 46RE schematic and cant find a PID regulator or any
>> means
>> > to do
>> > this. There is a mechanical (hydraulic) regulator the should "fix"
>> the
>> > maximum pressure under any condition though... I have missed
>> something
>> > obviously. The transgo guys will be getting a call...
>> > Bruce
>> > At 07:25 PM 7/30/98 -0000, you wrote:
>> > >While not entirely familiar with how the Chrysler computer controls
>>
>> > >transmission line pressure, I AM familiar with the way GM does it.
>> > The
>> > >PCM on most late-model GMs only handles part-throttle line
>> pressure.
>> > WOT
>> > >shifts are not effected.
>> > >
>> > >That is where shift kits come in. They help the WOT firmness and
>> > speed
>> > >of the shift, as well as through the entire operating range of the
>> > >transmission. Of course, with the mods you make to the tranny with
>> > the
>> > >shift kit, it is usually recommended you do NOT modify the line
>> > pressures
>> > >with a computer program, as at part throttle, line pressures tend
>> to
>> > be
>> > >so high that they can cause damage and premature tranny failure.
>> > >
>> > >Gene Beaird
>> > >98 Flame Red CC R/T
>> > >95 DGGM Impala SS
>> > >
>> > >>The JET (both Stage I & Stage II) chips do firm up the shifts and
>> > change
>> > >>
>> > >>the shift points. Don't no know about the rev. or top speed
>> > limiters,
>> > >>give them a call.
>> > >
>
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:09:17 EDT