Locking Hubs On A Rear Dana 44

Well, now I'm really confused.

JW, if the transfer case should "fall into gear" while being flat towed it will spin up the transmission. And if the transmission is also in gear it will spin up the engine. I've seen a crankcase ventilated by a connecting rod from that very scenario (not a Jeep). Wouldn't happen if the transmission is in neutral.

jeepdaddy, why should the mainshaft spin if the transfer case is in neutral? By definition, "neutral" means the driveshafts are disconnected from the transmission.

What am I missing?

 

It's called parasitic drag. It's where the fluid moving around a gear can make it spin. When the rear driveline spins, it moves oil around in the t case. This can other gears to spin due to the fluid motion. If it causes the bullgear to spin, then the transmission mainshaft spins as well. Putting the transmission in gear eliminates this.
A lot like putting a fan in front of another fan and then turning it on.

 

Right. I wondered if that could explain it. Bigger effect than I expected. Thx.

 

I'll say the drag difference could be significant. Don't forget when the D18 is placed in NEUTRAL, the front driveshaft is locked to the rear (at least with a single shifter transfer case). This causes the front driveline to spin during flat tow with the rear driveshaft connected.
For this reason, I always disconnect the rear for flat tow.

 

Twin stick D18 is one stick for front live vs dead
the other is high, neutral, low
That's what allows the 2wd low with a twin stick when you remove the pill allowing 6 combinations of 2,4 / H,N,L

If you pull the rear driveshaft off entirely to flat tow you can lock the hubs and put it in 4wd to drive around (or stay if your transfercase parking brake works)

Towing with the Expedition it was a 10% difference in fuel economy without the rear driveshaft vs turning the rear shaft, parking brake, and transfercase output.
The windshield was a greater difference at 15%
(It'll get better mpg towed than on it's own)

 

OK; that's why I qualified my response.
I couldn't remember if the twin sticks were entirely independent or not.
My old Power Wagon had two sticks. It had to have the front axle stick fully engaged (pulled back) prior to pulling the high/neutral/low stick back.
And I understand the pill removal trick, but that's for advanced users...otherwise case damage could occur.
Gosh, the only reason I pulled up this old thread was to research more about the WARN full float conversion kit.

 

Yeah, I'm not sure anymore in factory form it was 09 when I pulled the pill on mine.

I thought the pill allowed 2wd neutral having a relief in the high-neutral rail... The entire concept of the interlock drives me nuts, the t-98 allows the same load on the rear axle with granny hi 2wd, and the little Surry Gala has an entire transfercase locked in low without a front differential at all?

Anywho, it's easier to reassemble without and makes parking the 4000lb camper a big slice O' pie.