All-Wheel Drive and "Park"
#1
All-Wheel Drive and "Park"
Greetings! Another forum has hashed this over to the point that I can get little out of it.
The claim is that AWD as used on Explorer will allow the vehicle to "creep" forward or backward, if it is on an incline with trans. in "Park".
I have maintained the claim cannot possibly be true.
Would anyone comment, please? Need clarification! Thanks!
impish
The claim is that AWD as used on Explorer will allow the vehicle to "creep" forward or backward, if it is on an incline with trans. in "Park".
I have maintained the claim cannot possibly be true.
Would anyone comment, please? Need clarification! Thanks!
impish
#3
I used to have an exploded view of these transfer cases that show the input and rear output shafts were directly connected, with the front output shaft being driven off the rear through a fluid-clutch mechanism. I can't find it right now. Maybe someone else has one they can post.
Anyway, I have heard about the drift theory before. If the truck drifts in park on a hill, it isn't the AWD transfer case. Unless the rear driveshaft has been removed. I had this happen to a friend's Explorer a couple years ago, and he drank the Kool Aid over this theory of design flaw and was ready to sell the truck for scrap. Ended up being a problem in the tranny.
Anyway, I have heard about the drift theory before. If the truck drifts in park on a hill, it isn't the AWD transfer case. Unless the rear driveshaft has been removed. I had this happen to a friend's Explorer a couple years ago, and he drank the Kool Aid over this theory of design flaw and was ready to sell the truck for scrap. Ended up being a problem in the tranny.
#5
I told them "bull****", and they tried to talk me out as some kind of un-knowledgeable fool!
Here's what I think: Only way the viscous clutch can allow torque flow to the front driveshaft is if it's INPUT feeds off the transmission output shaft, and it's OUTPUT feeds torque to the front driveshaft, while the rear driveshaft is ALSO receiving torque from the trans. OUTPUT. This means in PARK the rear wheels are locked to the park pawl in the trans., and the front driving system takes NO PART in the operation of "Park".
They actually went so far as to INSIST that if the front driveshaft is REMOVED, there will be NO PARK action atv all, in "Park", and the vehicle will ROLL!
Whaddaya all think? I expect to test this gibberish when I get back home (next April) where I have a '98 V-8 AWD with screwed-up steering waiting to be fixed (it still drives). Thanks for your input! impish
#6
What they say is true of the AWD system on an Aerostar, but the Aerostar and the Explorer do not use the same AWD system. Perhaps that is what they are basing their information off of. In you remove the front driveshaft on an AWD Aerostar, the vehicle will roll, but not only that, it will only move in gear until the planetary lockup overheats and fails.
As I said, the setup on the Explorer is not the same unit, the Explorer is a more solid unit, much heavier duty, and it does engage the lockup on the rear driveshaft, specifically to address the issues learned on the Aerostar.
Point #2 in agurment against these ignorants. Neither the Aerostar nor the Explorer use a viscous clutch. Both designs use a planetary that functions much like a locking differential. They will allow a slightly different shaft speed on the front a rear, but if that allowable difference is exceeded, typically 5%, an electronically engaged clutch locks the gears, creating a 1:1 direct drive ratio on both shafts. This design will allow the shafts to spin at slightly different speeds, but it won't turn unless both shafts are free to spin.
If they are trying to bash Ford, the AWD system used in many of the Astros and Blazers is a viscous clutch. The viscous clutch does not give a direct drive to the front shaft. That setup is unlikely to creep either unless the rear driveshaft is disconnected.
As I said, the setup on the Explorer is not the same unit, the Explorer is a more solid unit, much heavier duty, and it does engage the lockup on the rear driveshaft, specifically to address the issues learned on the Aerostar.
Point #2 in agurment against these ignorants. Neither the Aerostar nor the Explorer use a viscous clutch. Both designs use a planetary that functions much like a locking differential. They will allow a slightly different shaft speed on the front a rear, but if that allowable difference is exceeded, typically 5%, an electronically engaged clutch locks the gears, creating a 1:1 direct drive ratio on both shafts. This design will allow the shafts to spin at slightly different speeds, but it won't turn unless both shafts are free to spin.
If they are trying to bash Ford, the AWD system used in many of the Astros and Blazers is a viscous clutch. The viscous clutch does not give a direct drive to the front shaft. That setup is unlikely to creep either unless the rear driveshaft is disconnected.
#7
Any '96-2001 5.0 AWD Explorer or Mountaineer will creep if the front drive shaft is removed. We on the "other forum" know whay we are talking about. The "other forum" has been around for more than 10 years.
I had it happen on my 97 Mountaineer a few years ago when I had to replace my drive shaft.
I had it happen on my 97 Mountaineer a few years ago when I had to replace my drive shaft.
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#11
And now Ford gives us the car based pieces of junk. They should have dropped the Explorer name. It's like Chevy bringing back the NOVA name for their early 80's Toyota built scrap.
#12
Just chiming in only as an observer. I own a 96, but it is the auto 4WD. With that being said, I also own a 2001 F350 and a 77 F150 with 9" lift and 40" tires. To say that the Exploders ended with the 02 model based on independent suspension is ludicrous. The front end on the 95 and later is a farce. If you include them in the "real" category, then you are already including a souped up car suspension as viable in a 4WD. If it is good enough for the front, then it should be good enough for the rear. Call them what they are, an AWD grocery getter that can tow a trailer. Of course, you can also tow a trailer with your front wheel drive Buick, but that doesn't make it a truck. The Exploder is still a decent and capable vehicle for what it was designed for, that is, mainly driving around on the roads, and the independent suspension allows it to do that admirably.
#13
Just chiming in only as an observer. I own a 96, but it is the auto 4WD. With that being said, I also own a 2001 F350 and a 77 F150 with 9" lift and 40" tires. To say that the Exploders ended with the 02 model based on independent suspension is ludicrous. The front end on the 95 and later is a farce. If you include them in the "real" category, then you are already including a souped up car suspension as viable in a 4WD. If it is good enough for the front, then it should be good enough for the rear. Call them what they are, an AWD grocery getter that can tow a trailer. Of course, you can also tow a trailer with your front wheel drive Buick, but that doesn't make it a truck. The Exploder is still a decent and capable vehicle for what it was designed for, that is, mainly driving around on the roads, and the independent suspension allows it to do that admirably.
Second one was a '99 2WD with a 5-speed manual. Not a lick of trouble with that baby, either! (Both '96 & '99 were OHV V-6s).
Could not resist an '04 4WD with SOHC V-6, 92K on it, seller desperate, had taken a job in Alaska, left Expl. with mother-in-law in Missouri. Wanted $9,000, I bought it for $7,000, a good buy, I figgered. It is immaculate cosmetically. Torque Converter Solenoid bombed at 101K, I replaced the module of them, put in new juice, it's running beautifully.
But, all this is going off-thread. Sorry. Thanks for the input! impish
#14
I have a 1997 Explorer All Wheel Drive...
I have over 175k on mine and have had no problems with the drive train. It is (by far) the best vehicle I have ever driven in snow and ice. It's actually difficult to make it slip! I have driven it plenty of times off road, as well, and it has never left me stranded. I'm not comparing it to a rock crawler or a hard core 4X4 with 40" tires, but it does well for what it's designed for.
I have never had a problem with it creeping on an incline in park. How can it creep when the parking pawl is engaged inside the transmission? The following information is accurate for the AWD transfer case:
All Wheel Drive (Borg Warner 4404)
DESCRIPTION
The all-wheel drive transfer case is a two-piece aluminum, chain driven, viscous clutch type unit. This produces a system in which all-wheel drive is always activated. All-wheel drive transfer case is automatic and has no external controls.
The viscous clutch is a torque distribution device. It is non-repairable. The internal construction of the viscous clutch consists of alternating plates that are connected to the front and rear outputs of the transfer case. The viscous clutch is filled with a high viscosity fluid which flows through slots in the plates. The resistance to shear causes the plates to transmit torque at the needed ratio. The ratio that torque is transmitted at is approximately 35% front and 65% rear.
A front differential compensates for the difference between the inner and outer wheels. However, when one driveline component travels farther than another, there will be driveline or torsional windup that must he released.
OPERATION
Torque is transmitted through the input shaft to the planet carrier assembly. Torque flow continues through the gear ring to the rear output shaft. Torque also flows from the planet carrier assembly to the sun gear shaft, which is splined to the drive sprocket. The drive gear is connected to the driven sprocket by the drive chain. Torque continues through the driven sprocket to the front output shaft flange. The viscous clutch provides the connection between the gear ring and the sun gear shaft.
There are four transfer cases available for the Ford Explorer 1995-2001:
BW 1354 Manual Shift, 4X4
BW 1354 Electric Shift, 4X4 (push button 4WD)
BW 4404 Viscous Drive, AWD
BW 4405 Electronic Shift, Auto 4X4
I have never had a problem with it creeping on an incline in park. How can it creep when the parking pawl is engaged inside the transmission? The following information is accurate for the AWD transfer case:
All Wheel Drive (Borg Warner 4404)
DESCRIPTION
The all-wheel drive transfer case is a two-piece aluminum, chain driven, viscous clutch type unit. This produces a system in which all-wheel drive is always activated. All-wheel drive transfer case is automatic and has no external controls.
The viscous clutch is a torque distribution device. It is non-repairable. The internal construction of the viscous clutch consists of alternating plates that are connected to the front and rear outputs of the transfer case. The viscous clutch is filled with a high viscosity fluid which flows through slots in the plates. The resistance to shear causes the plates to transmit torque at the needed ratio. The ratio that torque is transmitted at is approximately 35% front and 65% rear.
A front differential compensates for the difference between the inner and outer wheels. However, when one driveline component travels farther than another, there will be driveline or torsional windup that must he released.
OPERATION
Torque is transmitted through the input shaft to the planet carrier assembly. Torque flow continues through the gear ring to the rear output shaft. Torque also flows from the planet carrier assembly to the sun gear shaft, which is splined to the drive sprocket. The drive gear is connected to the driven sprocket by the drive chain. Torque continues through the driven sprocket to the front output shaft flange. The viscous clutch provides the connection between the gear ring and the sun gear shaft.
There are four transfer cases available for the Ford Explorer 1995-2001:
BW 1354 Manual Shift, 4X4
BW 1354 Electric Shift, 4X4 (push button 4WD)
BW 4404 Viscous Drive, AWD
BW 4405 Electronic Shift, Auto 4X4
#15
I will have to agree with Mountain Man...
When he said, "IMO the Explorer died in 2001. One independent suspension is one too many let alone 2.
And now Ford gives us the car based pieces of junk. They should have dropped the Explorer name. It's like Chevy bringing back the NOVA name for their early 80's Toyota built scrap."
The '95-'01 still have a full frame under them and are a half ton truck - capable of carrying as much weight as a Ranger pickup, and the AWD's can tow more than a Ranger. After '01 they went to a uni-body "car-like" design which is why I have no intention of getting rid of mine in the foreseeable future. What's more is, up to '98 they still had steel bumpers in the front for more security in a wreck. Before I got my pickup, I once hauled 1,256 lbs of bricks in the back of my Explorer without any problems.
And now Ford gives us the car based pieces of junk. They should have dropped the Explorer name. It's like Chevy bringing back the NOVA name for their early 80's Toyota built scrap."
The '95-'01 still have a full frame under them and are a half ton truck - capable of carrying as much weight as a Ranger pickup, and the AWD's can tow more than a Ranger. After '01 they went to a uni-body "car-like" design which is why I have no intention of getting rid of mine in the foreseeable future. What's more is, up to '98 they still had steel bumpers in the front for more security in a wreck. Before I got my pickup, I once hauled 1,256 lbs of bricks in the back of my Explorer without any problems.