FAD vs CAD trivia question ❔

[982500h]

Just something that I've been wondering since I first heard about the FAD on current Jeeps. When did the Center Axle Disconnect (CAD) become the Front Axle Disconnect (FAD)? Years ago it was common on some vehicles to have either auto hubs or CAD. Now everyone talks about FAD. Best I can tell is CAD and FAD are the same thing. And no, I don't believe FAD is more descriptive. CAD has always referred to the front axle, and I can't think of any vehicle that has had rear CAD. While FAD clarity comes from describing the front axle, CAD clarity is the method of disconnecting at the center of the axle--versus at the hubs.

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[GATORB8]

Maybe vacuum vs electric?

 

[brewski]

Does anyone besides Jeep call it FAD? It could simply be a marketing term for Jeep. Kinda like how DCT transmissions are never called DCT, but every brand has their own acronym for it, PDK, DSG, etc
The YJs had a CAD (IIRC) which was problematic and it could be jeep avoiding that marketing disaster.

 

[982500h]

The YJs had a CAD (IIRC) which was problematic and it could be jeep avoiding that marketing disaster.

True. That would make sense because many early CAD (not just Jeep) were vacuum operated and had a terrible reliability reputation. Of course, auto hubs weren't much better.

 

[GATORB8]

Does anyone besides Jeep call it FAD? It could simply be a marketing term for Jeep. Kinda like how DCT transmissions are never called DCT, but every brand has their own acronym for it, PDK, DSG, etc
The YJs had a CAD (IIRC) which was problematic and it could be jeep avoiding that marketing disaster.

Current Ram 3500 calls it FAD in the parts catalog. 1500 is a short "axle" with CVs for the IFS, look like it's "Front Axle Locker Actuator".

Not sure on the Ford SD, My last F150 had Vacuum Actuated Hubs (IFS). IIRC auto hubs on the TTB Bronco.

 

[grimmjeeper]

CAD was a thing in Jeeps back in the 80's. Jeep dropped it completely though in favor of "normal" axles and ran them from the mid 80's until the JL came out. So more than 30 years without a disconnect.

The XJ had a disconnect that's a lot like the current setup as far as location goes. But it was vacuum operated. The full size Jeep Wagoneer in around 83-84 actually had the mechanism cast into the differential housing on the passenger side. It too was vacuum operated. It also only came with the Selec-Trac transfer case (NP228 and NP229 back in the day). If you got Command-Trac (NP208) you got manual locking hubs instead. The J10 and J20 pickups were the last of the Jeep axles with the NP208 and locking hubs in 1988. After that, the pickup was discontinued. The Grand Wagoneer continued through 1991 but with no CAD (and fixed hubs).

It wasn't until the JL came out that the "FAD" name came to be in a Jeep. It may have shown up earlier in Ram trucks. No idea why they changed the name from CAD to FAD but they did.

 

[982500h]

It wasn't until the JL came out that the "FAD" name came to be in a Jeep. It may have shown up earlier in Ram trucks. No idea why they changed the name from CAD to FAD but they did.

Now I'm really curious when the first use of FAD occurred on any vehicle.

 

[GATORB8]

Now I'm really curious when the first use of FAD occurred on any vehicle.

Maybe the GM 8.25 in 98? Don't really see the abbreviation though, just "front axle disconnect".

 

[Nailgun]

Maybe the GM 8.25 in 98? Don't really see the abbreviation though, just "front axle disconnect".

GM first used it on the 8.25 IFS in 1988 with the launch of the 4th Gen C/K series. The design remains almost unchainged to this day with a few minor revisions to the actuator motor. Originally it used a expanding 'wax' material that when heated, moved the fork....then upgraded to a simple gear driven electric motor. It's been very durable.

I worked a GM actuator into my Jeep YJ to create an electric CAD that operated similar to the vacuum system.

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