What do you maen by lockouts. This is an all time AWD. Locking hubs are impossible. Someone correct me if I am wrong in my thinking, but to use the lockouts without destroying the transfer case, you would need a conventional transfer case and all the headache involved with installing it. In my opinion, that would be a step backwards. This is a minivan, not a jeep.

 

There is only one stock AWD aero in Lugansk, 4.0 Auto.

Other have manual t-case, locking hubs, one of them has solid front axe, like RB's aero....

.... about awd vechicles.... Better off-road ability - longer walk to find a trucktor ore bettter tank to tow toyr truck out of deep mud.....

 

I was thinking of some form of manual locking transfer case to be used with the front hubs that can be disengaged. But it's sounding like a lot of hassle to install these parts.

Thanks to Rick for the explanation of the planetary differential. But I'm still trying to picture the drives: The planetary cluster is driven by the engine from the front of the gear set, then on the back side, the sun gear drives a chain that drives the front prop shaft, but I'm not sure how the ring gear then delivers power to the rear drive train.

However, it seems to me that another way may work better: The sun gear connects directly to the rear drive shaft, while the ring gear drives the chain through an attached gear. This makes more sense to me in another way: The planetary cluster, being of greater effective diameter than the sun gear, will have a >1 torque multiplication factor driving it, and the ring gear, being of a larger diameter, will have a <1 torque multiplication on it, thus achieving the difference in torque split. Then I can see a clutch pack between the sun shaft and ring gear that's engaged by an electromagnet to lock the two together.

While I really like the AWD of my Aero, I do not believe that it will work very well off-road.

 

few rigs off the dealers' showroom floors will work well off-roading without major mods

too much easily torn off or broken $10,000 plastic. too many lines and wires hanging down to be torn off. $500 aluminum wheels look like hell after one rock gouge. most run too hot in ultra slow speed driving and overheat with cooked tranny and engine.

Hummer H1 maybe

 

I heard that T-case of Ranger ore explorer may be used on aero to make on demand AWD. I dont remember what auto-hubs fit aero, but I know it is possible. Here enthusiasts use parts from local junk yards, where american trucks are very rare so they often use UAZ axes, becouse they were designed for military purpuses and it is easy to put manually-locking diff. inside them.

About my friend's aero. When all the diffs are locked his van wont turn on skid road. Slowly runs straight with front wheels turned to lock......

 

OK, for starters, if the internal gear was connected to the front drive chain and the sun was connected to the rear driveshaft (without changing the tooth numbers on them), then you'd wind up with a 67/33 split, with the majority going to the front. This is certainly a viable alternative for some applications, but it effectively make the Aerostar behave like a FWD vehicle. No more power-on oversteer, that's for sure. It would also substantially increase the duty cycle of the Dana 28 front axle and reduce it on the 7.5" rear axle. Not ideal, at least not with a much heavier front axle. There are ways to route the outputs so that they both exit out the rear of the differential concentricly, with the internal gear connected up the middle with the sun output around it. It's more complicated then I can explain readily though. But trust me, that issue isn't a real big deal. There are far more complicated cases out there then the Aerostar's.

Yes, without the clutch to lock the center, you're stuck with 3 open diffs. Well, unless you can an LSD in the rear. But if both rear wheels were on ice and spun, without the clutch you'd just sit there. If one front wheel is also on ice, even with the clutch, you're still going to sit there because there's nothing to transfer additional torque to the one front wheel with traction. So you'd spin three wheels. The only way out of a three-wheel traction loss is to have a locking feature or a high-performance LSD front, center, and rear. Then you're covered regardless of which wheel looses traction. Unfortunately, we no options for the front axle, given that it's a ******* that's unsupported by the aftermarket. If the Ranger/Explorer SLA front axle could be adapted to the van (it's very similar), then that would open up a couple of options for LSD/lockers and gear ratios...

The transmission in the Aerostar is the same A4LD/4R55/5R55 depending on year as the Ranger and Explorer had. So the transfer cases from those vehicles would bolt straight up. So, if you wanted a manual-shifted 2 speed case, you could do it, assuming you found a nice spot to poke the shifter up through the floor. You could also use the on-demand Explorer case that has an electromagnetic clutch (similar to the Aerostar's) to engage the front axle when needed, and defaults to RWD when not. But you'd have to keep live hubs for that to work, unless you wired it with a simple manual switch like was discussed for the Aerostar transfer case clutch.

I think that covered all the key areas. If not, oh well...

 

If the Aerostar were remade, I think they should go with a design similar to the dana 28, but I do think that LSDs should be used on both the front and rear axles. The transfer case itself should be a little bit stronger, and there should be a switch inside that defaults to the auto position, which would cause it to behave like our van do now. But the switch could also be set to a lock or offroad position, that locks the unit in place without burning out the clutch. It should remain in that position until you either turn it off, or until you turn the vehicle off in which case it defaults back to auto. And then of coarse you can disable it by unhooking the control module. For 95%+ of the users out there, this would be the best setup. Exactly the same but better.

 

I concider Manual T-case + manual hubs to be the best solution. Our company owns one small AWD truck of '70s. Manual tranny, manual T-case, manual hubs. All the summer hubs are in off position, all the winter in on position. Tranny and T-case were never rebuilt (so reliable). In front axe bearings and joints are replaced every 3-4 years.... Good reliable solution.

 

Yes, manual t-case and hubs are reliable, but the AWD system is safer. On top heavy vehicles, manual locking can be very dangerous on dry pavement. Vans are designed for a different type of people and driving than trucks and SUVs. Vans are used by soccer moms who rarely know how to drive a stick these days. The AWD system on the Aerostar is reasonably reliable as is, most problems are related to failed speed sensors.

 

What exactly makes a manual locking hub very dangerous on dry pavement?

 

1. Tranny may be damadged
2. Van may loose its ability to stay on curve
3. All 4 wheels may skid in case of too widly open throutle. Releasing gas pedal may cause more skidding.

But what a reason to use locking on dry surface???? There are different purpose of different AWD systems. Ones are made for deep mud like Jeep CJ, HMMV, russian UAZ, GAZ66, well known ford F250 with manual tranny, other are designed for snow, like Niva, ZIL 131, Ural Truck... Many cars have AWD for better stability, fast acceleration and safety on skid roads, loke Volvo S-series AWD, Ford Focus AWD, Audi Quatro, Subaru, Mercedes S600 4matic....

AWD of aero is a compromise. It is made for better off-road ability, but designed for driving by soccer moms who used to drive old good RWD sedans with autos, and just becouse 70% of torque is given to rear axe to prevent skidding of all 4 wheels if soccer mom press gas pedal too much. She may be knows whot to do if rear axe skids, but if all the axes skid she must know what axe skids faster and what direction to turng steering wheel.... 50/50 AWD gives driver more abilities, but driver must be trained well. I used to drive Niva w/o any ASR, ABS, SBS and ESP. I know what is it

 

It is also much easier to roll a vehicle that is locked in 4WD high on dry pavement. The binding can preload the suspension and litteraly spring that thing over. I have actually seen this happen. Granted in the experience I saw the driver was not that skilled, but he had the truck locked in 4WD high, was going about 45. He too a sharp turn, and you could see the truck lean a little bit and then snap inwards as the tires slipped to release the tension, which then leaned back outwards a bit further, snaped back in again, and then leaned right over and rolled twice. He had made similar dirt on dirt before, but on dirt is is constantly releasing the bind through smaller amount of slippage without the violent release as found on pavement. Just by watching this, you could clearly see what happened. The more top heavy the vehicle, the more likely this is to happen. Also, the larger the tires the more liekly this is to happen.

 

That's great guys, and as an LSD & AWD system engineer I'm familiar with why you don't lock a diff or transfer case on dry pavement. My question was:

What exactly makes a manual locking hub very dangerous on dry pavement?

 

Exessive tire wear, t-case damage, U-joints and CVs damadge....

 

I don't know that a manual locking hub is dangerous in particular. If you leave the front axle locked it could reduce your turning radius, but beyond that I don't think that would be an issue.