Blown
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I thought I would start a thread here, will help me organize and it might help someone else. I am going to try and swap-in a Ford Aerostar Dana 28 Tranfer Case. I want AWD, do not need 4lo, and should still have the ability to lock the transfer case for really slippery or deeper stuff. My thought is better handling and no rear wheel spin.
The 1997 Ford Aerostar got a new 5-speed automatic transmission for '97 (the 5r55e). The 5-speed came only with the 4.0-liter engine, which was standard on E-4WD Aerostars. My rig has the 5r55e so it should bolt-up.
Aerostar E4WD system (my summary and cut n paste from http://www.ford-trucks.com/forums/460401-aerostar-transfer-case.html:
"Aero's have a system that is not designed to run with the transaxle clutch in lockup all the time. The electronic four-wheel drive vehicle has engine torque available to all the wheels on a full-time basis (All Wheel Drive). 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. AWD is made possible by use of a planetary gear differential. For 4wd a control module senses wheel slip and locks up the interaxle differential as necessary via an electromagnetic clutch. 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. When the clutch pressure plates are compressed, the front and rear wheels rotate at the same speed and the front planet does not operate giving a 50/50 split to the front and rear axles.
Regarding the clutch engagement duration, the word I have from the Aerostar's former AWD system engineer is that engaging it manually with a switch would actually be a little easier on the clutch, since it had a fair amount of torque capacity and that leaving it engaged (in foul conditions and such) would potentially extend the life of the clutch because it would eliminate the continuous slippage from repeated engaging/disengaging that you might encounter on a bad road...The auto system would engage for 3 seconds, disengage, then reengage if it sensed slippage I think under 5mph. The on, off, on, off must have made for a weird jerky ride when it got traction."
The 1997 Ford Aerostar got a new 5-speed automatic transmission for '97 (the 5r55e). The 5-speed came only with the 4.0-liter engine, which was standard on E-4WD Aerostars. My rig has the 5r55e so it should bolt-up.
Aerostar E4WD system (my summary and cut n paste from http://www.ford-trucks.com/forums/460401-aerostar-transfer-case.html:
"Aero's have a system that is not designed to run with the transaxle clutch in lockup all the time. The electronic four-wheel drive vehicle has engine torque available to all the wheels on a full-time basis (All Wheel Drive). 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. AWD is made possible by use of a planetary gear differential. For 4wd a control module senses wheel slip and locks up the interaxle differential as necessary via an electromagnetic clutch. 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. When the clutch pressure plates are compressed, the front and rear wheels rotate at the same speed and the front planet does not operate giving a 50/50 split to the front and rear axles.
Regarding the clutch engagement duration, the word I have from the Aerostar's former AWD system engineer is that engaging it manually with a switch would actually be a little easier on the clutch, since it had a fair amount of torque capacity and that leaving it engaged (in foul conditions and such) would potentially extend the life of the clutch because it would eliminate the continuous slippage from repeated engaging/disengaging that you might encounter on a bad road...The auto system would engage for 3 seconds, disengage, then reengage if it sensed slippage I think under 5mph. The on, off, on, off must have made for a weird jerky ride when it got traction."
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