Why no "Auto" function Transfer Case?
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Elder User
Joined: Aug 2006
Posts: 634
Likes: 2
Why no "Auto" function Transfer Case?
Would be nice to have a better transfer case, rather than just a straight up "Part-Time" unit. Basically a "Full-Time" (center differential) system for more on-road options with no driveline windup. 
Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
Full-time 4x4 requiring a center diff would make the transfer case much bulkier and heavier, and would add cost to the truck. There would also need to be some method of controlling center diff slip - whether viscous coupling, multi-plat clutch, or manual lock. Pickup truck customers seem pretty content with part-time systems. Part time systems are also easier to make more durable.
Cargo Master
Joined: May 2007
Posts: 3,336
Likes: 4
From: Western New York
The Ramcharger and Trailduster Chrysler offerings from 1971-79 both offered full time 4wd models. They featured the NP203 fulltime transfer case with a center differential. In spite of its heavier design for fulltime service the chains and sprockets would wear and eventually the chains would jump under even mild acceleration sending a heavy jolt throughout the vehicle. They were very expensive to rebuild and normal life was between 75K-100K miles. These models also featured an innovative front wheel bearing system which was also prone to failure. Two sides of a large cast iron sphere held the bearing which had to be shimmed to hold the race and the tapered rollers together and support the weight of the vehicle and keep the front camber correct. There used to be a lot of these running around with a "knock kneed" appearance since it was a trial and error method of shimming by disassembling and re-assembling the housing and a generally disliked and misunderstood repair. These repairs were best accomplished with a "For Sale" sign.
Junior User
Joined: Oct 2012
Posts: 68
Likes: 0
From: Hunter
The Ramcharger and Trailduster Chrysler offerings from 1971-79 both offered full time 4wd models. They featured the NP203 fulltime transfer case with a center differential. In spite of its heavier design for fulltime service the chains and sprockets would wear and eventually the chains would jump under even mild acceleration sending a heavy jolt throughout the vehicle. They were very expensive to rebuild and normal life was between 75K-100K miles. These models also featured an innovative front wheel bearing system which was also prone to failure. Two sides of a large cast iron sphere held the bearing which had to be shimmed to hold the race and the tapered rollers together and support the weight of the vehicle and keep the front camber correct. There used to be a lot of these running around with a "knock kneed" appearance since it was a trial and error method of shimming by disassembling and re-assembling the housing and a generally disliked and misunderstood repair. These repairs were best accomplished with a "For Sale" sign.
Cargo Master
Joined: Aug 2010
Posts: 3,221
Likes: 63
One word - economy.
As to the NP 203/205 - where you guys getting your info on the NP203 being junk?
Cargo Master
Joined: Aug 2010
Posts: 3,221
Likes: 63
The Ramcharger and Trailduster Chrysler offerings from 1971-79 both offered full time 4wd models. They featured the NP203 fulltime transfer case with a center differential. In spite of its heavier design for fulltime service the chains and sprockets would wear and eventually the chains would jump under even mild acceleration sending a heavy jolt throughout the vehicle. They were very expensive to rebuild and normal life was between 75K-100K miles. These models also featured an innovative front wheel bearing system which was also prone to failure. Two sides of a large cast iron sphere held the bearing which had to be shimmed to hold the race and the tapered rollers together and support the weight of the vehicle and keep the front camber correct. There used to be a lot of these running around with a "knock kneed" appearance since it was a trial and error method of shimming by disassembling and re-assembling the housing and a generally disliked and misunderstood repair. These repairs were best accomplished with a "For Sale" sign.
Tuned
Joined: Jun 2016
Posts: 463
Likes: 86
On this topic, how does one optimally handle an up hill, unprotected left turn, across traffic, in slick (wet) conditions?
The light duties w/ a rear LSD and "4-Auto" can squirt across the street like a scalded cat but I'm concerned about how to do this in a much heavier Super Duty.
This might seem like a corner case but I run into it every day.
The light duties w/ a rear LSD and "4-Auto" can squirt across the street like a scalded cat but I'm concerned about how to do this in a much heavier Super Duty.
This might seem like a corner case but I run into it every day.
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Cargo Master
Joined: May 2007
Posts: 3,336
Likes: 4
From: Western New York
I did not say it was junk. I did say there was a common problem of chains and sprockets wearing and hence the tendency for the chain to jump on the sprocket prematurely to the life of the vehicle. I helped a friend change one out under 100K miles and another friend in a driveline shop said they were being brought in regularly for rebuild and often times replace after drivers failed to fix them in a timely manner after the chain started jumping. The whole system although a reasonable idea limited the trucks to 8-10mpg with the 360 engine. The 318 might have been a little better but there was a lot of iron to spin just to go straight down the road. And yes it was an inexpensive way for New Process Gear to create a full time 4WD.
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Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
On this topic, how does one optimally handle an up hill, unprotected left turn, across traffic, in slick (wet) conditions?
The light duties w/ a rear LSD and "4-Auto" can squirt across the street like a scalded cat but I'm concerned about how to do this in a much heavier Super Duty.
This might seem like a corner case but I run into it every day.
The light duties w/ a rear LSD and "4-Auto" can squirt across the street like a scalded cat but I'm concerned about how to do this in a much heavier Super Duty.
This might seem like a corner case but I run into it every day.
Alternately, add weight. The truck will behave with much better.
Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
I did not say it was junk. I did say there was a common problem of chains and sprockets wearing and hence the tendency for the chain to jump on the sprocket prematurely to the life of the vehicle. I helped a friend change one out under 100K miles and another friend in a driveline shop said they were being brought in regularly for rebuild and often times replace after drivers failed to fix them in a timely manner after the chain started jumping. The whole system although a reasonable idea limited the trucks to 8-10mpg with the 360 engine. The 318 might have been a little better but there was a lot of iron to spin just to go straight down the road.
Cargo Master
Joined: May 2007
Posts: 3,336
Likes: 4
From: Western New York
On this topic, how does one optimally handle an up hill, unprotected left turn, across traffic, in slick (wet) conditions?
The light duties w/ a rear LSD and "4-Auto" can squirt across the street like a scalded cat but I'm concerned about how to do this in a much heavier Super Duty.
This might seem like a corner case but I run into it every day.
The light duties w/ a rear LSD and "4-Auto" can squirt across the street like a scalded cat but I'm concerned about how to do this in a much heavier Super Duty.
This might seem like a corner case but I run into it every day.
Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
One thing I prefer about part-time 4x4 is you get an idea about conditions and traction before you need 4WD. If you're sliding all over the place or aren't making it uphill very well, time to engage 4x4 and you are well aware of the slippery conditions. In the past, when I drove Land Rovers with permanent 4x4, you never really felt how slippery it was because they went so well, but that could lull you into taking a corner too fast or not leaving enough time for braking.
JMO
JMO
Cargo Master
Joined: Aug 2010
Posts: 3,221
Likes: 63
I did not say it was junk. I did say there was a common problem of chains and sprockets wearing and hence the tendency for the chain to jump on the sprocket prematurely to the life of the vehicle. I helped a friend change one out under 100K miles and another friend in a driveline shop said they were being brought in regularly for rebuild and often times replace after drivers failed to fix them in a timely manner after the chain started jumping. The whole system although a reasonable idea limited the trucks to 8-10mpg with the 360 engine. The 318 might have been a little better but there was a lot of iron to spin just to go straight down the road. And yes it was an inexpensive way for New Process Gear to create a full time 4WD.
I would say my experience was probably limited to trucks under 100K. I specialized in engines and drive trains and although a did do a few of those 200 pound ,monsters I would say compared to the rest of the heavy repairs I did the ratio was relatively small.
Thinking back I would guess I did as many of the cast iron transfer cases that I did of the Dana 60 and 70 axles - very few.
Tuned
Joined: Jun 2016
Posts: 463
Likes: 86
Sometimes I start in 4x4 and pull out straight to get moving, disengage 4x4, and then make the turn. The momentum carries me through. Works best with manual 4x4 shift, though, because you can disengage quicker.
Alternately, add weight. The truck will behave with much better.
Alternately, add weight. The truck will behave with much better.
Tuned
Joined: Jun 2016
Posts: 463
Likes: 86
Sounds like the extra bed weight should take care of the scenario for me.
