Looking for advice on overdrive (4R100) - Diesel Forum - TheDieselStop.com
'99 & up 7.3L Power Stroke Engine and Drivetrain Discussion of the '99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 08-09-2018, 02:59 PM Thread Starter
Junior Member
 
Join Date: Jul 2018
Posts: 23
My Photos: (0)
Feedback Score: 0 reviews
Looking for advice on overdrive (4R100)

When I bought by SuperDuty 350 back in June it was my first Diesel. The previous owner said he always turned OD off when coming to a stop, and turned on around 40 mph.

Is this a pretty normal practice or just being over cautious? And maybe he meant for driving around town at slower speeds, not sure. Thanks
Big Horn is online now  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 08-09-2018, 03:24 PM
RT
Lifetime Supporting Member
Lifetime Supporting Member
 
RT's Avatar
 
Join Date: Dec 2009
Location: Texas
Posts: 13,781
My Photos: (0)
Feedback Score: 0 reviews
Clicking the OD button does provide some engine braking - seems to keep the converter locked up as well as the coast clutch on deceleration. That's probably why he was doing it. Definitely not required and won't make anything last longer except your brakes. I wouldn't mess with it.

2003 F-250 XLT Crew Cab 7.3L, Chrome BigTex Grille Guard, Quad pillar - 3 ISSPRO gauges (trans, pyro, boost) and DP-Tuner F6; Roush fuel pressure / temperature / oil pressure gauges, Ford Severe Duty AIS, 31 row 6.0 transmission cooler, ScanGauge II, Marinco mod, Walker BTM

I wonder if clouds ever look down on us and say, "Hey, look - that one is shaped like an idiot!"
RT is online now  
post #3 of 9 (permalink) Old 08-09-2018, 04:39 PM
Senior Member
 
Join Date: Dec 2002
Location: Tucson, Arizona
Posts: 321
My Photos: (0)
Feedback Score: 0 reviews
I've wondered whether having the overdrive function default to being off and found once that there was a modification to do that. It was called the DT301 Intermotive Duratrans Programmable Overdrive Controller. So you install this thing, I guess, and by default, the overdrive stays off and you use the button to turn it on when you want it on. Has anyone installed that?

Bob

2000 F350 4x4, AIS, 203F Tstat, SS EGR Tube
robertth is offline  
 
post #4 of 9 (permalink) Old 08-09-2018, 04:39 PM
Senior Member
 
FleetMan's Avatar
 
Join Date: Aug 2001
Location: Western WA
Posts: 1,929
My Photos: (0)
Feedback Score: 0 reviews
When towing or descending long grades, I will normally disengage the OD to take advantage of the additional braking forces. If you are going to employ this practice, disengage the OD before starting down the hill and your speed builds up to the point you need to apply the brakes to slow down to about 5 mph below your desired coast speed. Repeat this cycle until you feel comfortable reengaging the OD and going on your merry way.

------------------------------------------------------------------------------------
Early 99 F250 PSD (XLE4) XLT, Extended Cab, Short Bed, 4X2, BTS Trans/TC, 3.73 Limited Slip, Transfer Flow 48 Gal. Mid-Ship Tank
Western WA - Member since August 2001

Last edited by FleetMan; 08-09-2018 at 04:43 PM.
FleetMan is offline  
post #5 of 9 (permalink) Old 08-09-2018, 07:25 PM
Lifetime Supporting Member
Lifetime Supporting Member
 
bigb's Avatar
 
Join Date: Nov 2003
Location: Arizona
Posts: 1,309
My Photos: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by FleetMan View Post
When towing or descending long grades, I will normally disengage the OD to take advantage of the additional braking forces. If you are going to employ this practice, disengage the OD before starting down the hill and your speed builds up to the point you need to apply the brakes to slow down to about 5 mph below your desired coast speed. Repeat this cycle until you feel comfortable reengaging the OD and going on your merry way.
Does the TC unlock when you hit the brakes? And will it re-lock when you take your foot off the brakes? With OD disengaged of course.

Brian, Tucson, Arizona
02 F350 4x4 CREW 7.3 160K, BFG Rugged Terrain 285s, AIS, Isspro pyro, boost & tranny temp pillar pod, Dipricol coolant temp, ELC, Isspro EV-2 Fuel Pressure & HPOP, Dieselsite boots, coolant & tranny filters & 203* Stat, 6.0 Tranny Cooler, ITP pre pump tank mod, Bellowed Up Pipes, Riffraff Frx, netbook mount with AE, GPR LED, Stancor, Red Head steering gear, Battery Tender & 2 Marincos.
bigb is offline  
post #6 of 9 (permalink) Old 08-10-2018, 04:26 PM
Senior Member
 
FleetMan's Avatar
 
Join Date: Aug 2001
Location: Western WA
Posts: 1,929
My Photos: (0)
Feedback Score: 0 reviews
The torque converter stays locked up all the time, descending grades on the highway and steep hills in town. Examples, westbound I-84 going into Pendleton, OR or the James Street hill in Kent, WA.

------------------------------------------------------------------------------------
Early 99 F250 PSD (XLE4) XLT, Extended Cab, Short Bed, 4X2, BTS Trans/TC, 3.73 Limited Slip, Transfer Flow 48 Gal. Mid-Ship Tank
Western WA - Member since August 2001
FleetMan is offline  
post #7 of 9 (permalink) Old 08-11-2018, 10:20 AM
NYB
Senior Member
 
Join Date: Mar 2008
Posts: 873
My Photos: (7)
Feedback Score: 0 reviews
Quote:
Originally Posted by bigb View Post
Does the TC unlock when you hit the brakes? And will it re-lock when you take your foot off the brakes? With OD disengaged of course.

YES. But it depends on the PCM calibration. Some calibrations commanded the TC to unlock every time the service brake pedal is touched, regardless of OD engagement or disengagement, and irrespective of speed.


I have one of those calibrations. And I have a TC lock/unlock indicator LED that provides visual confirmation when the TC is locked, unlocked, or in the process of locking (the pulse width modulation command circuit flutters the LED indicator light when engagement is in process). These calibrations are typically earlier model years, model year 2000 and below.


On the other hand, some PCM calibrations factor in vehicle speed before unlocking the TC when the service brake is touched, and do not unlock right away if the vehicle speed is above approximately 40 mph, even if the brake pedal is touched. On these calibrations, if the vehicle speed is below X (where X is around 35 mph) and the brake is touched, then the TC will unlock. These calibrations are typically found in later model years, 2001 and above.


Nowadays, one cannot go by earlier or later model year to determine calibration. Too many people run chips and/or tunes where the calibration is modified. Even where folks report that they are running on their so called "stock" tune setting in their Hydra or flip chip or programmer, that "stock" tune is often a simulation of a stock tune, not the actual stock tune of the base pcm. And the simulated stock tune can be based on a more popular stock PCM calibration that has been found over the years to be preferable.


And one of those calibration preferences is preventing the TC from unlocking any time the service brake pedal is touched. The way Ford transmission engineers initially programmed TC unlocking on brake application has frustrated many Super Duty owners who, while descending a grade, just want to tap the brake briefly for a touch, say when someone in front of them turns on their turn signal to switch into their lane. They don't want to suddenly gain MORE speed as their transmission free wheels into a fluid coupling while they are barreling down hill with a trailer at 55 mph.


Tuners know this, and have either tuned that annoyance out of their simulated stock tuning, or have selected a later Ford calibration upon which to base their entire tuning platform. And this is what makes BigB's question hard to answer based on other user reports with their model year. Because unless the person reporting knows the base calibration of their tune (even in the stock setting), or knows whether or not their PCM has ever been changed or flashed (which might rely on continuous ownership of their truck since brand new), it isn't possible at this point entering into the 20th year these trucks have been in service to know.


But 19 years ago, we DID know, and we did comment, on this very forum, how much it sucked having the TC unlock immediately on service brake application. Aftermarket products (ie, Banks Smart Lock), home spun solutions (ie TC lock/unlock switches), and numerous tunes were created to surmount this problem until Ford finally fixed it.
NYB is offline  
post #8 of 9 (permalink) Old 08-12-2018, 05:58 PM
Lifetime Supporting Member
Lifetime Supporting Member
 
bigb's Avatar
 
Join Date: Nov 2003
Location: Arizona
Posts: 1,309
My Photos: (0)
Feedback Score: 0 reviews
Thanks for that very detailed reply NYB! I'll need to watch TC Slip on Torque Pro next time I am mountain driving!

Brian, Tucson, Arizona
02 F350 4x4 CREW 7.3 160K, BFG Rugged Terrain 285s, AIS, Isspro pyro, boost & tranny temp pillar pod, Dipricol coolant temp, ELC, Isspro EV-2 Fuel Pressure & HPOP, Dieselsite boots, coolant & tranny filters & 203* Stat, 6.0 Tranny Cooler, ITP pre pump tank mod, Bellowed Up Pipes, Riffraff Frx, netbook mount with AE, GPR LED, Stancor, Red Head steering gear, Battery Tender & 2 Marincos.
bigb is offline  
post #9 of 9 (permalink) Old 08-12-2018, 10:45 PM
Senior Member
 
Join Date: Aug 2007
Location: California
Posts: 1,517
My Photos: (0)
Feedback Score: 0 reviews
Quote:
Originally Posted by NYB View Post
YES. But it depends on the PCM calibration. Some calibrations commanded the TC to unlock every time the service brake pedal is touched, regardless of OD engagement or disengagement, and irrespective of speed.


I have one of those calibrations. And I have a TC lock/unlock indicator LED that provides visual confirmation when the TC is locked, unlocked, or in the process of locking (the pulse width modulation command circuit flutters the LED indicator light when engagement is in process). These calibrations are typically earlier model years, model year 2000 and below.


On the other hand, some PCM calibrations factor in vehicle speed before unlocking the TC when the service brake is touched, and do not unlock right away if the vehicle speed is above approximately 40 mph, even if the brake pedal is touched. On these calibrations, if the vehicle speed is below X (where X is around 35 mph) and the brake is touched, then the TC will unlock. These calibrations are typically found in later model years, 2001 and above.


Nowadays, one cannot go by earlier or later model year to determine calibration. Too many people run chips and/or tunes where the calibration is modified. Even where folks report that they are running on their so called "stock" tune setting in their Hydra or flip chip or programmer, that "stock" tune is often a simulation of a stock tune, not the actual stock tune of the base pcm. And the simulated stock tune can be based on a more popular stock PCM calibration that has been found over the years to be preferable.


And one of those calibration preferences is preventing the TC from unlocking any time the service brake pedal is touched. The way Ford transmission engineers initially programmed TC unlocking on brake application has frustrated many Super Duty owners who, while descending a grade, just want to tap the brake briefly for a touch, say when someone in front of them turns on their turn signal to switch into their lane. They don't want to suddenly gain MORE speed as their transmission free wheels into a fluid coupling while they are barreling down hill with a trailer at 55 mph.


Tuners know this, and have either tuned that annoyance out of their simulated stock tuning, or have selected a later Ford calibration upon which to base their entire tuning platform. And this is what makes BigB's question hard to answer based on other user reports with their model year. Because unless the person reporting knows the base calibration of their tune (even in the stock setting), or knows whether or not their PCM has ever been changed or flashed (which might rely on continuous ownership of their truck since brand new), it isn't possible at this point entering into the 20th year these trucks have been in service to know.


But 19 years ago, we DID know, and we did comment, on this very forum, how much it sucked having the TC unlock immediately on service brake application. Aftermarket products (ie, Banks Smart Lock), home spun solutions (ie TC lock/unlock switches), and numerous tunes were created to surmount this problem until Ford finally fixed it.
Fascinating! Now I know the answer to a question I had wondered about for years. Why my truck maintains a constant speed without gaining speed while going down hills.

2001 F350 XLT 4X4 crew cab, dual rear wheels, long bed, black, 7.3l turbo diesel, automatic transmission, 4.10, shift on the fly, running boards, sliding rear window, 38 gal fuel tank, Odyssey extreme 65-PC1750T batteries, Michelin LTX-MS2 rear tires, Sumitomo Encounter front tires, Shell Rotella Ultra elc, 11,500 gvwr, 20,000 gcwr, 7500 gvw, completely stock, 114,000 miles when purchased, now has 240,000 miles, repairs so far: two starters, batteries, cps, brakes, tires, alternator, ball joints, locking hub, wheel hub, AC compressor, serpentine belt, power steering pump, driver's side window, ignition switch, o-ring, Spectra premium radiator, water pump, fan clutch, fan blades, thermostat, thermostat housing, tensioner. Stolen twice so far, but recovered both times with major damage.

2005 Nomad Rampage toyhauler made by Skyline. 11,500lb gvwr.
DonWarkentin is offline  
Sponsored Links
Advertisement
 
Reply

  Diesel Forum - TheDieselStop.com > 1999-2007 Ford Super Duties > '99 & up 7.3L Power Stroke Engine and Drivetrain

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Diesel Forum - TheDieselStop.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome