Torsen Rick is right, believe the man who builts and sells stuff Tougher than Ford.

Aero's have a weak marginal AWD system that is not designed to run with the transaxle clutch in lockup all the time.
You will know when the clutch kicks in by the computer. The first time it did on me I was pushing snow with the front bumper and slide off the road somewhere I should not have been, Oh S???, sat there for awhile red faced, put it back into drive, eased the gas on, the AWD clutch kicked in, the wife laughed from joy and away we went, right around a big real 4wdr Bronco that was in over his head and not going anywhere.
turned around and got the hell out of snowed in Dodge.

Transfer Case System, E-4WD
The Dana TC28 transfer case (7A195) is mounted on the rear of the transmission (7003) and operates full time. The control module, located under the driver's seat, actuates the transfer case clutch under adverse conditions.
The electronic four-wheel drive vehicle has engine torque available to all the wheels on a full-time basis. This improves vehicle handling and traction during difficult driving conditions.
The control module senses wheel slip and locks up the interaxle differential as necessary via an electromagnetic clutch. This is an automatic function and does not require any driver input.

The transfer case receives engine torque through the transmission. One third of the torque is sent to the front axle. Two thirds of the torque is sent to the rear axle. This torque split favoring the rear axle allows the vehicle to handle in the manner of a rear wheel drive vehicle but with the response of a front wheel drive vehicle. This function is made possible by use of a planetary gear differential.
The planetary gear differential delivers torque to the front and rear axles while allowing both axles to turn at different speeds. This is especially important when the vehicle is turning because it prevents driveline "wind-up." During difficult driving conditions (wet or slippery roads) the transfer case can send all necessary torque to the front or rear driving axles to maximize vehicle traction.
The control unit senses when a wheel is slipping and activates the electric clutch assembly in the transfer case. The electric clutch consists of an actuator coil, an armature and clutch pressure plates (7563). When the clutch pressure plates are compressed, the front and rear wheels rotate at the same speed and the front planet (7A398) does not operate. The control unit engages the clutch for approximately 3.3 seconds and then releases it. If wheel slip continues, the clutch will re-engage after approximately .5 seconds and will continue to cycle as long as slip conditions exist. The driver may notice a slight pushing or bumping sensation as vehicle traction increases.
The control unit will not allow the clutch to engage when both of the following conditions are present: the vehicle is going 8 km/h (5 mph) or faster and the service brakes are applied. Also, the clutch will not engage when the transmission selector is in the park or neutral positions.

 

I wouldn't say that the AWD system was weak or marginal. The axles are, for sure, but the AWD system itself was pretty state of the art in 1990.

Given the electronics of the time, it did a pretty good job, and the full time center diff gives the vehicle better dynamic behavior then an on-demand part time 4WD system would have. In truth, there are a number of modern AWD vehicles on the market today that have conceptually very similar AWD systems, improved only by the use of modern electronics and sensors. It was actually somewhat a head its time.

From what I was told by the Aerostar's AWD system chief engineer (who we now work with on new projects at Ford), the clutch was fairly beefy and had good torque capacity. I think the only problems with the AWD system as a whole are the dated electronics...

 

for what the aero awd system was designed for, it is adequate, winter highway snow icy driving with no real operator control and little or no maintainance. most still on the road have probably never seen a front diff. or transfer case oil change.
most owners get into trouble and difficulties trying to use them for unintended uses with resulting failure

for any real 4 wheeling, the aero is less than adequate and weak. heavy deep mud, deep 12" + snow, deep ruts, pulling or towing a disabled rig on rough logging roads for a distance.

 

I'll give you that, but that isn't what the design intent is. The same could be said for the AWD in an Audi S4. And yet that car (and its AWD) does what it was intended to do very well... Why on earth would you get an Aerostar to go mudding?

 

don't ever take on a V8 Audi Quattro AWD on a logging road even with a 580 ci stroker Ford F250 4wdr
the A6 is a real sneaker. German wolf in sheep's paint and body.
Ford losses every time even in the mud.
there is an owner's group that races (unofficial) here in the Cascades range, no speed or traffic enforcement of course.

 

That's the one I need. Thanks for taking the time to look up and post the numbers for me. I appreciate it. How much do you think shipping will be to zip code 19543? Thanks!!

Ian

 

Bump.......

 

sorry, been offline for a while due to gardening and stripping the spare parts van, PM me an address and I'll get it on it's way ASAP

 

sorry for the delay, it's been sitting in a jiffy bag on the sofa awaiting one of us to hit a post office, should be sorted after this weekend.

 

Thanks for the update, and I look forward to it's arrival. Thanks again!

 

The module arrived yesterday (thanks again x.l.r.8...I'll get a check out to you for the shipping costs asap). I plugged it in today, and am still having trouble. The origional problem with the driveline bind-up is gone, but it's still flashing Code 2 (I even disconnected the batter for a few minutes to try to clear it), and the RABS is acting goofy. The ABS has been acting goofy since I unplugged the module...pulses real hard and has been busting apart shoes...and it's still doing it with the new module. Anyone have any ideas or should I just set this thing of fire and be done with it?

 

Just jumping on board here as I also have AWD issues. So let me get this straight. You just replaced the AWD module and improved things. I do not know how that relates to the ABS circuitry. Maybe someone can enlighten me on that. But at this time I would move your repair to an ABS issue (replace that module) .

 

I'm assuming (and we all know what that spells. lol) that it's related to the AWD module, because the ABS seems to be a piggy-back system to it...the rear vehicle speed sensor that that reads the tone ring on in the rear differential and controls the ABS module is tied into the AWD harness, and the brake problems began when I removed the AWD module. Also, I'm not getting the ABS light (lights up upon start up as it should, but doesn't remain on or flash a code).

 

Ramtuff:

I don't think the AWD system has anything to do with the ABS. The ABS uses the speed sensor on the rear differential. The AWD system uses two speed sensors, front and rear, and both are located right on the Transfer Cases. You may have a problem with one of the sensors on the Transfer Case. Just unplug the wiring and remove them from the TC, very easy to do. The sensors have three prongs on each. probe the resistances between the prongs. They should be about 1000, 2000 and 3000 ohms respectively, within 200 ohms or so. If not, they are busted.

Regards

 

My aero is 2wd but this poor guy does have a point about the expense. Is it possible to simply install a switch on the dash to engage 4wd. Sounds kind of cool to me with no computer demons to deal with.

Ken