Offroad Marketing Part Time Kit?

Tore into the NP203 for a rebuild. Was expecting 100% stock because that was what the PO told me, which at the time seemed odd. There were manual locking hubs installed and he told me he did this to save MPG back in the 80's. I asked if the transfer case was converted at the same time - he said no. Well found this installed. From what I can tell from some google searching it appears this was patented by a company called Offroad Design. But beyond on that I cannot find anything else. How popular were these compared to the full shaft conversion?

And now I am facing a dilemma. I am in the process of converting it back to full time 4WD (OEM set up). I already secured and installed OEM axle hub slugs. But now with this conversion installed I am missing the 4 spider gears and thrust washers. They seem to be available at National Drivetrain for about $100 total. Wondering if this is still the right path forward. The truck will not be a daily driver, just something for weekend cruising and fun. I like the idea of bringing it back to OEM and the full time 4WD. Fuel economy is of no consequence for its intended use. Thoughts?

Also, for anyone who has done one of these conversions. It appears there is a spacer, 2 thrust washers and a torrington bearing installed with the conversion. These are all present. But I am assuming none of these belong in there if I convert back to OEM. Is this correct?

Offroad Design is a current company that specializes in 4x4 squarebody parts. The biggest supplier of those kits used to be Mile Marker and there was 2 different versions. One was more involved to install, but was said to be more durable. I also know there were some minor internal design changes with the 203, and you have to have the right parts to convert back to full time 4x4.

I'm not sure of any other details as I've never done the swap myself.

From my experience with ORD they’ll be happy to answer your questions.
I can’t see paying to swap back to full time 4x
Doesn’t make any sense to me, even if you don’t mind about MPG today maybe you will 10-15 years down the road.
Maybe you wanna drive to the mud/ mountains. Besides mpg big tires locked in 4x on the road just sucks

I would leave it as it is. Your truck is going to drink gas with the added drag on the driveline. Full time 4×4 chews up the front tires also.

Driving a full time case is nothing like driving a part time case shifted into 4 high. There's give between the front and rear, it's not as extreme wear on parts like everyone makes it out to be.

I had a Power Wagon years ago with the NP203 AWD. It's a different driving experience. My understanding at the time was... The 203 has an open differential that can be locked for true 4wd so it doesn't bind in AWD HI or LO like say a 208 or 205 or a 241 or 261 driven in 4H or 4L. It will bind in HI LOC and LO LOC because the diff is locked making it regular 4wd.

hatzie said:

I had a Power Wagon years ago with the NP203 AWD. It's a different driving experience. My understanding at the time was... The 203 has an open differential that can be locked for true 4wd so it doesn't bind in AWD HI or LO like say a 208 or 205 or a 241 or 261 driven in 4H or 4L. It will bind in HI LOC and LO LOC because the diff is locked making it regular 4wd.

Click to expand...

Exactly, when they are in Hi or Low the power goes to which ever wheel wants to lose traction. NOT fulltime at all, worked well when locked in.

Sorry, my mistake and typo. The company that originally patented this kit was Offroad Marketing corp.

The picture in the patent matches my part(s) exactly (fig 5) -



Seems the inventors were Karol & Teddy Vanzant.



Here is a link to the patent -

https://patents.google.com/patent/US4304317

OK, one more fun tidbit I also found by searching on the inventors names. Seems they sued Mile Marker for patent infringement and lost. So it would seem they invented this type of part time conversion, but felt it was stolen by MileMarker (or Skyjacker). Interesting.



https://law.justia.com/cases/federal/appellate-courts/F2/915/1583/94634/


Nonetheless, I am still planning to start a search for the 4 planetary gears and misc. From some other searching I did find at least 1 post where the author was quite critical of this particular conversion because of the wear on the planetary 'cross' (where the planetary gears ride). I can see how that could happen pretty easily, but luckily mine is in good shape. No wear or marks whatsoever. I am wondering whether just locating used 203 chain section might be better/cheaper. With so many split over the years to steal the gear section for 205 doublers, I expect they should be plentiful and cheap. Will do some eBay and Craigslist searching....

I never liked how my trucks drove with the full time 203 case. It was really hard on the front end when driving on the street. Both of my trucks in the early 90's had the Mile Marker kits with the replacement output shaft. Unfortunately, they don't sell that kit anymore. It replaced everything that is shown exploded in Figure 4.

I agree, leave the part time kit and the lockouts in it, they make the truck drive a bunch better by keeping the front axle unlocked until you want or need it.
Mark

I ONLY support returning the truck to OE as both GOD and the General (Motors) intended.

I had the 203 stock and swapped a 205 twin stick from offroad design as soon I had the money. I didn't like the feel of the 203 in 4hi. It was kind of unpredictable as power is send to the tire with lowest resistance.
I had open diffs too, but installed limited slips with the 205. I really like the rwd with limited slip which I use most of the time.Ride sway better than before.
I would keep the 2d conversion.
Just my 2 cents.

Thanks for the input from everyone. New plan. I am going to move ahead with putting the 203 back into the truck, in full time 4WD form, and will replace it with a 205 after the resto is complete. This will buy me some time to deal with gathering up the 205 and associated parts for the 205 swap.

The reason I am sticking with the short plan on converting back to full time 4WD is because I think it will be cheaper. I have already sunk money into locating and installing a good set of OEM slugs for the frt axle. At this point all I need for finish the full time conversion is a set of planetary gears, or a complete used diff. Given all of the 203's that have been divided for use as doublers I am assuming tracking down a used diff section should be easy and cheap. Having said that so far I can't find anything.

Does anyone have a used 203 diff or know where I can find one? I cannot seem to post in the 'wanted' section.

Thanks.

Most 203's have been scrapped by now.