RE: Re: Looking for highly tech. info. about OD

From: Bernd D. Ratsch (fasstdak@hotmail.com)
Date: Thu Jul 15 2004 - 20:04:27 EDT


Bob.

I posted an answer to your OD question in another topic. Here's the reply:

I did some research on the OD function and there is no OD Engage/Disengage
function in the PCM (myth). It's controlled via speed, throttle position,
load, and the switch on the shift lever. Lockup can occur even when the
switch is disengaged (locks up the converter in 3rd rather). All the switch
does is disable 4th/overdrive gear (5th in the 45/545RFE transmission).

My bet, since it's random...is that you have a bad switch or solenoid
(OD/Clutch solenoid pack). I dbl-checked without shop foreman on this and
he agrees on this as well.

Switching the OD button to OFF forces lockup in 3rd gear rather than in 4th.
(Lockup can occur even in 2nd though in specific scenarios.) As for the OD
memory location in the PCM and how it "remembers"...myth.

- Bernd

-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bob Tom
Sent: Thursday, July 15, 2004 1:39 PM
To: dakota-truck@dakota-truck.net
Subject: Re: DML: Re: Looking for highly tech. info. about OD

At 11:18 AM 7/15/04, you wrote:
>Other option is race WITH OD on. I'm assuming you are bracket racing.
>Times will be slower, but at least consistant. TonyC

I've been thinking of doing that for this weekend's bracket races for the
consistency. Years ago, I would, on "occasions", forget to set OD OFF and
run at least 2/10s slower :-) The way it is now, I would even be hard
pressed to earn a point in the Jr. Dragster class :-P

Bob



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