NP203 Part Time Conversion Questions
 

I'm looking to purchase either the mile marker 502 part time conversion kit with manual hubs or the full shaft replacement kit to convert my np203 to part time four wheel drive. After reading some walkthroughs on the conversion and a video overview I'm feeling confident enough to take on the project myself on my DD. If I do the conversion (shaft or 501/502 kit) with the transfer case in my truck how long can I expect it to take?

After talking to a mechanic my dad has used he said he's had experience converting them saying it would cost a couple hundred bucks because you have to tear the transfer case apart and it takes hours. From what I've read though people say with the transfer case outside the truck you can swap the components in an hour if you know what you're doing. This makes me doubt taking it to someone and wasting my money.

Looking though the walkthrough on colorodok5, http://coloradok5.com/milemarkerpt.shtml and watching this short video to see what I'm up against, , I don't see this being a multiple hour, couple hundred dollar job.

So, if I go to tackle this by myself I have one very newbish question having never worked with drivelines before. How do I disconnect the drive shaft like the first step in the coloradok5 walkthrough shows?

Also, for four wheel drive vehicles it looks like the speedo gear is inside the transfer case, is this correct? My speedometer is currently 20% or so off because I have a 67-72 on a later 73-? frame. Would anyone know what color /teeth speedo gear is needed to make a 67-72 speedo work with an np203? Or should I just use the gear ratios/tire size and comparison of my speedo with a GPS to find the number of teeth I'd need (I'm planning on getting larger 33" tires right after the conversion)?

Any info/tips with the conversion and the speedo gear swap would be appreciated, thanks!

Edit:

I also forgot, which would be recommended for just a daily driver application, the 501 kit or the full shaft replacement?
Also how and how easy is it to replace the factory slugs with manual lockout hubs?

Re: NP203 Part Time Conversion Questions
 

Stop and think what a shop charges for Labor $50.00 Plus per hour , thinking into taking it R&R plus the time to do the conversion.Do you have the tools and jack to lower the T-case down ,do you have help? By not knowing how to take down the drive shaft I would buy a Service Manual and start reading to make sure you want take it on.

Re: NP203 Part Time Conversion Questions
 

Here are the instructions for the Doug Nash shaft kit I had installed in the 80's . MM now has the rights and the instructions look the same except for the name. You don't have to remove the transfer case or tear it completely a part, only the back two aluminum housings. Since I would be working without a lift, I would budget 4 hours, including cleaning up the parts, etc. A shop that does it all the time might be able to do it in a couple of hours.

From what I have read the shaft is better than the other type which relies on a wafer bearing to maintain clearance and end play. When the bearing goes, things move and back things happen like broken cases. But there are a lot of them out there and guys swear by them. Do your research and come to your own conclusion. Mine was in my DD from 85 to 2000 for around 60,000 mile and saw lots of off road use hunting, etc. with no problems. My biggest hassle was the crappy shifter, a search will turn up my conversion to twin stick.

While it is out you can replace the speedo gear, do a search there has been a discussion on how to figure out which one your want.

The hubs are easy, pull the slugs and follow the instructions with the hubs. Again, do a search, there have recently been a couple of threads with some good tips on hub R&R.

Re: NP203 Part Time Conversion Questions
 

i've had both milemarker kits, do the shaft if anything, it eliminates a ton of annoying driveline slop the 501 kit has which only gets worse with wear. have a service manual and time and patience if you wanna tackle it yourself getting the transfer case out is the easy part

Re: NP203 Part Time Conversion Questions
 

Another vote for the shaft. I had the 501 kit in my 78 blazer and blew the case into a million pieces... Hubs are no big deal. Get a good set of snap ring pliars.
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