5.0 awd transfer case

[SoNic67]

My 99 gets a solid 17 mixed driving and will pull almost 20 when it's mostly highway. I hooked up an ultra gauge and it shows 22-23 while cruising and my truck is almost stock (CAI and side exit catback with all 4 cats still in place). So I can definitely see his findings being true after doing the drive train mods.

My AWD gets 16.5 mpg mixed driving and 18-19 mpg on highway (depending of the actual speed).
If I stay at 60mph or drafting right behind a tractor trailer, I get 20mpg

 

[masospaghetti]

Probably because you're basing this off his driving habits vs what Ford said the 2wd was. I bet if he drove a 2wd version he would net better than Ford shows it got on the highway.

My 99 gets a solid 17 mixed driving and will pull almost 20 when it's mostly highway. I hooked up an ultra gauge and it shows 22-23 while cruising and my truck is almost stock (CAI and side exit catback with all 4 cats still in place). So I can definitely see his findings being true after doing the drive train mods.

You're missing the point. He's claiming that he went from 17/18 MPG to 23/24 MPG because he switched from a BW 4404 to the 4406 with manual hubs. He's attributing a huge gain in efficiency to this.

My point is that there's no way that swap will improve efficiency this much. You could remove ALL of the 4WD equipment and only gain 1 MPG (as shown by Ford's MPG numbers). The 4406 is still lugging around the front axle, bearings, driveshaft, and all of the moving parts inside the transfer case itself. And for what it's worth - the MPG penalty for Explorers with 4406's compared to 2WD setup was larger than the penalty between 4404 and 2WD. Different engines so it's not the perfect comparison, but I fail to see ANY compelling evidence that the 4406 will improve fuel economy.

 

[1997XLTRollover]

You're missing the point. He's claiming that he went from 17/18 MPG to 23/24 MPG because he switched from a BW 4404 to the 4406 with manual hubs. He's attributing a huge gain in efficiency to this.

My point is that there's no way that swap will improve efficiency this much. You could remove ALL of the 4WD equipment and only gain 1 MPG (as shown by Ford's MPG numbers). The 4406 is still lugging around the front axle, bearings, driveshaft, and all of the moving parts inside the transfer case itself. And for what it's worth - the MPG penalty for Explorers with 4406's compared to 2WD setup was larger than the penalty between 4404 and 2WD. Different engines so it's not the perfect comparison, but I fail to see ANY compelling evidence that the 4406 will improve fuel economy.

Ah ok I see your point. I'd like to know where all the other guys who did the swap are haha. In some of the swap threads guys are saying they got a nice improvement in power and mpg. If there's no real improvement I won't do this swap to my truck. If there is then I probably will.

 

[1997XLTRollover]

Ok let's see what happens here. Please don't turn this thread into a debate thread, but if you did actually do the swap and have your own data please post it up.

http://www.explorerforum.com/forums/showthread.php?p=3437290#post3437290

 

[imp]

A Simple Planetary Explanation

If ya wanna settle this bunch of questions about a "Planetary Gear Differential", here it is.

In a drive axle, the differential has to offer an infinite number of "ratios" between the two wheels. This ranges from one wheel spinning and the other standing still (the "highest" ratio") to both wheels spinning at equal speeds, when the "ratio" between the two wheels is then zero.

A planetary gearset only provides ONE ratio between input and output, thus, it could not serve as a true differential. We need to understand the meaning of "differential" as used in general: "A difference in speed between input and output power sources". imp

 

[masospaghetti]

The planetary gearset in the BW4404 allows for a infinite range of ratios so it would qualify as a true differential.

The VC provides a torque split but cannot transfer 100% of the torque to either axle, thus, there will be situations where there will be wheelspin and a difference in axle speeds. Otherwise, the 4404 would either be ON or OFF.

 

[imp]

The planetary gearset in the BW4404 allows for a infinite range of ratios so it would qualify as a true differential.

The VC provides a torque split but cannot transfer 100% of the torque to either axle, thus, there will be situations where there will be wheelspin and a difference in axle speeds. Otherwise, the 4404 would either be ON or OFF.

Please explain how a planetary gear-set can provide an infinite range of ratios? If it did, how or why would they call out a single reductionratio for a planetary?

If the sun gear is the input, and the planet carrier is held stationary, the reduction is 1:1; the whole thing turns at the same speed.

If the input is applied to the planet carrier, and the sun gear is held, the outer ring gear will revolve in a direction reverse to that of the planet carrier.

If the input is applied to the sun gear, and the outer ring gear is held stationary, the planet carrier will rotate in the same direction, but at a ratio determined by the relative numbers of teeth between sun gear and planet gears.

How in the hell can you say there are an infinite number of ratios available? Are no members held against rotation? imp

 

[masospaghetti]

It's hard to explain without having the TC open in front of me. From an operational point of view, the TC would not work if it only allowed a single fixed ratio. Ignore the VC; that would mean the front and rear axles are locked together in a fixed ratio, all the time.

I rebuilt my BW 4404 last year but I don't remember exactly how it was put together.