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.

 

I agree, but the Ford "auto" option in the F-150 is not really full-time 4x4...more like the front wheels quickly engage when slip at the rears is detected.

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.

 

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.

 

You beat me to it. The NP203 was a terrible unit in comparison to the 205.

 

One word - economy.

As to the NP 203/205 - where you guys getting your info on the NP203 being junk?

 

I guess all these deficiencies showed up after my 20 years working for a several of Dodge Chrysler Plymouth dealers.

 

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.

 

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.

 

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.

 

Land Rover ran full time cases for almost all of their models ever sold in the US. The permanent 4x4 Range Rover Classic used a center diff with a chain and viscous coupler unit...made by Borg Warner. Worked very well, but could fail after 100k miles. However, the Land Rover built case in the Discovery's and Defenders was gear-drive, 3.32:1 low range, and had a mechanical lock. Those were utterly indestructible and when my chain snapped on my '92 Range Rover, I replaced it with the Land Rover case from a Discovery.

 

At least for me I do not own a heavy duty truck to drive it like a scalded cat. If I were to want that performance I would start with 300 pounds in the bed over the axle so the tires were not being ground off at every intersection.

 

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

 

My purchased new 1978 Power Wagon, short bed 360 was a 12-14 MPG truck.

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.

 

Makes sense - thanks!

 

For sure - use right tool for the job and all that. I'm just concerned about being quick across that unprotected left once a day.

Sounds like the extra bed weight should take care of the scenario for me.