Ever wanted to use 4 LO gear in 2WD?
#1
12-31-2011, 11:31 PM
Ever wanted to use 4 LO gear in 2WD?
Sometimes over the years, I've used the lower gearing in my '77's transfer case using 4WD LO but simply leaving the front hubs unlocked for short pulls on pavement where I just wanted to use a very light throttle, but didn't need 4WD. Like moving loads of mulch or gravel or a loaded trailer up grade. Maybe you just need to haul the family and all the gear up Grandfather Mountain?
Same isn't so easy on my '07 FX4 as you all know. I thought of it sometime back, but I guess I didn't give the idea sufficient thought.
But then this past week we went to visit my BIL in Ga. and one evening, while sitting on the sofa chatting, watching a movie, looking through some stuff on my laptop in a saved file, I saw a copy of this thread I had pasted there last year. Almost immediately, a solution occurred. So simple too!
So I did a little bit of looking at other files, a Ford information sheet and my service CD for 05 and 08 F-150s .... and below is my idea.
So ...... that's where I'm at now, might fool with it tomorrow if it gets warm enough here.
Any thoughts?
Same isn't so easy on my '07 FX4 as you all know. I thought of it sometime back, but I guess I didn't give the idea sufficient thought.
But then this past week we went to visit my BIL in Ga. and one evening, while sitting on the sofa chatting, watching a movie, looking through some stuff on my laptop in a saved file, I saw a copy of this thread I had pasted there last year. Almost immediately, a solution occurred. So simple too!
So I did a little bit of looking at other files, a Ford information sheet and my service CD for 05 and 08 F-150s .... and below is my idea.
How to use 4WD LO reduction gearing in Transfer Case without locking IWEs
____________________________________________
Quoted from page 2 Ford publication 308-07A-1 ---- AND also on my Ford 2008 service CD "Transfer Case 4WD" Pg 2 of 131 ...same wording. (also see Ford 2008 service CD "Transfer Case 4WD" Pg 10 of 131 for more info on IWE Solinoid)
Let us say that I interrupt the wire (path) from IWE Solinoid to PCM on the ground side and install a simple two way DPDT switch,
use side 1 taps for IWE Solinoid wiring.
An "On(Off)On" type DPDT switch with center "off" position would kill the ground to the IWE Solinoid when parked in center position, thus causing the IWEs to lock independently of the PCM or dashboard 4WD switch position. Not sure that this has a practical use?
See "2008 Wiring", page 24 diagram, bottom right on Ford F150 CD.
Integrated Wheel Ends Solinoid has two leads off of it.
The above would all use just one set of the contacts or taps of a DPDT Switch.
Use the side 2 taps to activate a simple indicator lamp to light when the switch is flipped to keep IWEs open ( away from PCM control ).
____________________________________________
Quoted from page 2 Ford publication 308-07A-1 ---- AND also on my Ford 2008 service CD "Transfer Case 4WD" Pg 2 of 131 ...same wording. (also see Ford 2008 service CD "Transfer Case 4WD" Pg 10 of 131 for more info on IWE Solinoid)
Originally Posted by Ford Publications
The IWE system uses vacuum hubs that engage the front wheel hubs to the front halfshafts or disengage the front wheel hubs from the front halfshafts.
The IWE solenoid receives engine vacuum from the vacuum reservoir.
When the 4-wheel drive system is in 2WD mode, the 4x4 module (PCM) supplies a ground path to the IWE solenoid to apply vacuum to the integrated wheel ends (disengaging the front hubs from the front halfshafts). In 4WD mode, the 4x4 module (PCM) does not supply the ground path to the IWE solenoid, vacuum is not applied to the integrated wheel ends and an internal spring keeps the front hubs engaged to the front halfshafts.
The IWE solenoid receives engine vacuum from the vacuum reservoir.
When the 4-wheel drive system is in 2WD mode, the 4x4 module (PCM) supplies a ground path to the IWE solenoid to apply vacuum to the integrated wheel ends (disengaging the front hubs from the front halfshafts). In 4WD mode, the 4x4 module (PCM) does not supply the ground path to the IWE solenoid, vacuum is not applied to the integrated wheel ends and an internal spring keeps the front hubs engaged to the front halfshafts.
use side 1 taps for IWE Solinoid wiring.
- bring lead from PCM to "A" tap ( #2 below, Red lead to PCM )
- bring ground lead from IWE Solinoid to center tap,( #2 below, Red lead from IWE Solinoid )
- take a lead from "B" tap to ground.
An "On(Off)On" type DPDT switch with center "off" position would kill the ground to the IWE Solinoid when parked in center position, thus causing the IWEs to lock independently of the PCM or dashboard 4WD switch position. Not sure that this has a practical use?
See "2008 Wiring", page 24 diagram, bottom right on Ford F150 CD.
Integrated Wheel Ends Solinoid has two leads off of it.
- #1 Pink / Lt Blue lead goes to S105 and Fuse 11 which is a 10 Amp and "hot all time" at top rt page. ( See "Electrical Component Locations" Pg 18 of 49 and S105 location extreme right rear eng comp )
- #2 Red lead goes to #16 (circuit # 605 ) on Powertrain Control Module (PCM ) 4X4 SOL CONTRL C175B rt rr eng comp top left page. (C175B is in Harness 12A581 and shown in "Electrical Connector Views" Pg 25 of 179, 20 ga wire ) and this is the wire the PCM grounds / opens to control IWE Solinoid.
The above would all use just one set of the contacts or taps of a DPDT Switch.
Use the side 2 taps to activate a simple indicator lamp to light when the switch is flipped to keep IWEs open ( away from PCM control ).
- fused + power wire to bulb, then wire from bulb to switch center tap on side 2.
- take a lead from "B" tap side 2 to ground.
Any thoughts?
#2
01-01-2012, 04:18 AM
#3
01-01-2012, 12:52 PM
Tylus, I have the one CD that covers 04-08s, forget where I got it ..... maybe even from you? I don't rightly recall now ...... but Thanks for the confirmation!
I didn't know 250 guys were doing it.
To anyone that reads this thread and contemplates doing it ...... one thing to keep in mind is you are doubling torque applied to the rear driveline.
It's not a great idea to use the mod for WOT on hard pavement like drag racing, burnouts, etc ...
... as the low gearing in the TC was intended more for crawling on less than high traction surfaces I think.
But for moving weight at low speeds, it can reduce heat and stress on a transmission and allow less throttle to be used.
Thread
Thread Starter
Forum
Replies
Last Post
Bowie
1999 - 2003 7.3L Power Stroke Diesel
6
07-01-2014 07:10 AM
Iceman8984
1999 to 2016 Super Duty
9
07-10-2004 07:35 AM
