FAD delete, running out of options

[EbyCreek]

What signal does the FAD need to operate? Is it just a constant 12V? What is the current draw? Any wiring insite?

I’d like to be able to toggle my FAD manually to give me 2Lo… poor-man’s ATLAS.

This is how I added a FAD to my 392. Yours will be different as it sends a signal to the computer.

Pin 1 is Battery Positive (Ignition)
Pin 2 Controls Activation of the FAD... short pin to Ground to engage the FAD
Pin 3 is a return signal back to the DTC Module of a sensor of the position of the FAD actuator (not used for manual control of FAD on 392 Wrangler)
Pin 4 is Ground

Pin3 will send a voltage greater than 7.22 Volts back to the DTC Module to indicate
that the FAD was successfully engaged... if this is not true... then the FAD module is bad

So basically if you want to control the FAD manually...
Connect Pin 1 to Battery Positive (controlled by the ignition so you don’t power FAD constantly)
Connect Pin 4 to Ground

Engage FAD with a switch connected to ground on one side... and to Pin 2 on the other side

Here are the results:
Transfer case in 2wd FAD disconnected:
Pin 2: 12v
Pin 3: ~6.6v


Transfer case in 4wd FAD connected:
Pin 2: Ground
Pin 3: ~3.3v

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[JMP]

So converting from a stock functioning fad, would I only need to remove wire 2 from the stock wiring harness and rig it to a SPST switch to ground?

Will the computer freak out because it doesn’t see wire 2 anymore?

 

[EbyCreek]

I don't know. It would be a trial and error thing. Good luck

 

[Jtphoto]

Sounds like too much work for something that’s not beneficial.
Best to just do away with the FAD and run a one piece axle. Take all the weak components out of the equation.
If you are doing the FAD fix to gain mileage don’t bother. If you are doing it because of a driveshaft vibration, the FAD is not the fix.
FYI all Wrangler 392 and all Rubicons and Willys 2024 and up no longer have a FAD.

 

[EbyCreek]

The reason I added the FAD to my 392 was because of the aftermarket front driveshaft lube requirements. I have skid plates and Tom Woods recommends that his driveshaft CV joints should be greased every oil change. Adding 2 hours to the oil change to remove the skid plates and front driveshaft was to big of a pain in the ass. So for me having the FAD and reducing the CV lube requirements was worth it. If you are running a smaller lift with the factory front driveshaft then I would agree it's probably not worth it.

 

[Jtphoto]

The reason I added the FAD to my 392 was because of the aftermarket front driveshaft lube requirements. I have skid plates and Tom Woods recommends that his driveshaft CV joints should be greased every oil change. Adding 2 hours to the oil change to remove the skid plates and front driveshaft was to big of a pain in the ass. So for me having the FAD and reducing the CV lube requirements was worth it. If you are running a smaller lift with the factory front driveshaft then I would agree it's probably not worth it.

What makes it better with the FAD? You can run a double cardon driveshaft without a FAD. If you are getting vibes your pinion angle isn’t right.

 

[EbyCreek]

The lube requirements not a vibration problem.

 

[Jtphoto]

The lube requirements not a vibration problem.

Ok still not sure how the FAD has anything to do with lube requirements or driveshaft.

 

[EbyCreek]

The driveshaft lube requirements is based on miles. If the front driveshaft is not turning during your highway miles and only turns when you put the Jeep in 4WD. You have to use the Tazer to force 2WD along with the FAD keeps the front driveshaft from turning. This is if you have a fulltime 4WD as we do on the 392 Wrangler.

 

[Jtphoto]

The driveshaft lube requirements is based on miles. If the front driveshaft is not turning during your highway miles and only turns when you put the Jeep in 4WD. You have to use the Tazer to force 2WD along with the FAD keeps the front driveshaft from turning. This is if you have a fulltime 4WD as we do on the 392 Wrangler.

That makes sense.
To be honest I’ve had many trucks and Jeeps with double cardan driveshafts and only service them once a year. I put on between 20,000-30,000 miles a year. My JK had over 200,000 miles on it, over 100,000miles of that with a JE Reel double cardan driveshaft that never failed with a once a year service.
interesting that they would require it to be greased that often.

 

[EbyCreek]

See attached lube requirements from the Tom Woods website. If they ever lock up the damage can be catastrophic.

 

[Jtphoto]

Yes I’ve seen what happens. Same can happen if you tag the driveshaft on a rock and put a slight ding in it. There are a lot of tell-tale signs before they fail that bad.
Regular inspection especially after wheeling trips is important no matter how often you grease them.

 

[ArmyRN]

The TrueTracs are installed front and rear. Today is Wednesday, I'll pick it up on Friday. Kept the XR gear ratio 4.56. Total cost almost $4,000.

They used the Mopar FAD delete plate which I supplied. I have a Tazer in the Jeep, so I "deleted" the FAD in the computer (front axle "no").

One thing interesting. He told me my rear diff axle oil was a little burnt, and a carrier bearing was looking bad. So of course he replaced it. Probably caused by me flat towing my 3000lb flatty on a couple short trips (<100 miles each) and a 1500 mile round trip to Idaho and back on the highway. And then towing my 1500lb (when loaded) lil' adventure trailer all around Vancouver Island BC 1500 miles all total (about 1000 miles on the island itself).

TrueTracs require pure dino oil. No synthetics, no additives. I believe they put in 75/140w oil.

So we'll see how it feels driving it. Technically I shouldn't notice any difference.

 

[roaniecowpony]

Since I'm probably over 100:1 onroad vs offroad, I decided to keep FAD, even though I wanted to do rock crawling. I wasn't ready to move up to D60s or other large axles. So, I put in Dana chromoly axles and for the front, I used a combination of modified Dana chromoly axles and a RCV inner chromoly shaft and collar. Essentially, kept the OEM configuration, but with all chromoly shafts. My big worries with my setup are the OEM diffs with 2 spider gears and the FAD housing fracturing. As for trussing (such as Artec and Motometal style trusses), I just don't think they add a lot of strength. Castings tend to fail in tension. The top mounted truss does little to address that.

 

[ArmyRN]

So far so good. I've got a couple hundred miles on it now with the TrueTracs front and rear and the MOPAR FAD delete plate up front, and no issues. I don't notice any extra drag, MPG seems the same, and no funny feelings in the steering wheel.

I put it in 4WD the other day briefly just to see if any dash lights would come on. Nope. Tazer took care of the FAD signals up front.

This is the reason I didn't buy a Rubicon - I wanted to have TrueTracs front and rear instead of the Rubicon lockers. Bring on the snow.

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