question 4x4 on the fly engagement

[sjwelds]

The electric shift models have a clutch that will spin the front driveshaft to speed with the rear allowing the shift collar to engage without hubs being locked

Thought so. My 06 F150 4x4 is that way. Pretty sure the hubs lock after the driveline is up to speed. IIRC in the owners manual it says not to engage at speeds higher than 55 mph for that reason.

Anyhooooo not sure what the point would be of engaging on the fly without the hubs locked. Won't do any good.

JM2CW

 

[hce]

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Anyhooooo not sure what the point would be of engaging on the fly without the hubs locked. Won't do any good.

JM2CW

Older automatic hubs were engaged by the driveshaft turning.

 

[sjwelds]

^^^ Ah yes...

 

[jim_22]

The manual t-cases are considered shift-on-the-fly (4HI ONLY). The auto hubs are centrifugal, and are engaged BY the driveline. That is, when in 2WD, the front driveline is not turning, the hubs freewheel. When you shift the t-case to 4HI, the t-case engages the front driveshaft, the front axles shafts start to turn, and this locks the auto hubs. When you shift back to 2WD, the auto hubs remain locked, so the front driveline continues turning. You have to reverse for a few feet (8 feet, IIRC) to unlock the hubs.

Indeed, my truck wants a pretty good kick backwards to disengage.