Jeep front axle disconnect

RenegadeT

RenegadeT

no shirt,no shoes,no dice
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What magic innovation was discovered at Chrysler/Jeep in the early to mid 90s that prompted them to eliminate the front axle disconnect system on Dana30 front axles? As far as I know, there was no change in the transfer cases, besides the vacuum switch that sent a signal to the front axle shift fork solenoid. The front axle carriers are all the same, and the wheel unit bearing hubs may be different part numbers (for different thickness/offset brake discs and knuckles), but they are still all just bearings.

I have an 87 XJ and will be swapping in an engine/trans that will need a 23-spline NP231. I forgot about this vacuum disconnect nonsense, but my new 231 will probably not have the vacuum stuff. To get 4x4, I might lock the front axle shift fork to the locked position for now, then later swap in a one piece long shaft and seal, pull the disconnect mechanism, maybe drop a Locrite in while I have the carrier out to install the seal. So besides not having a dash light telling me 4x4 is engaged, will there be any downsides. I don't think so, but I'm really just kind of curious why AMC introduced the front axle disconnect system in the first place.
 
Fuel mileage gains I have to assume. Back in my dealership days we NEVER saw failed/worn front driveshaft centering balls on disco Jeeps. Less parts spinning = more MPG
 
The magic of long term testing.

I'd always assumed that the long term durability of the transfer case internals were in question, as the use of non-lockout hubs wasnt widespread. After they had enough experience to say it wouldn't be an issue, they ditched the disconnect for a fairly significant cost reduction.

Edit: "non-issue" should read as "acceptable" in engineering speak.
 
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