Need some clarification on the Mile Marker NP203 conversion kits

[mw67rs]

We I go the NP203 our of the truck. The transmission and engine will come out next. While I have the NP203 out I was considering using the Mile Marker shaft conversion kit to add part time 2wd. I have done some research on the kits they offer and it appears they sell a kit that utilizes locking hubs to achieve part time 2wd and another kit that changes out a shaft assy in the 203 to achieve part time 2wd. I have read that the shaft replacement kit is stronger.

Now my questions, with the shaft replacement kit my understanding is the engine will only drive one drive shaft and some of what I have read makes me think it drives the from drive shaft but I am not clear on that. The other differential and drive shaft will still be driven by the wheels but not the engine. Can locking hubs be installed in the un-driven wheels so they don't take up hp to drive the differential etc?

Thanks to anyone who can help clear this up for me.

[RIDE-RED 350r]

I don't see how any changes made to the 203 T-case would make it so the front wheels would cease to spin the front axles, diff, and front drive shaft..

I would think you would need to convert to lock-out hubs to accomplish this. Without lock-outs, there is no mechanism to disconnect the front driveline from the spinning of the front wheels.

Seems to me the T-case conversion makes it so you can isolate drive to the rear axle only for a "partial" conversion (for lack of a better word). To make the complete transition to part-time 4wd and fully neutralize the front driveline during 2wd use, the lock-out kit should do the trick.

I don't know how kosher this is, but I remember growing up as a kid my dad would pull the front drive shaft out of his '76 K-5 and put the 203 in Hi-Lock in summer. He never liked how it acted when turning tight on hot pavement in summer with the 203 I guess. I was pretty young so I don't remember the details.

[jlk]

http://67-72chevytrucks.com/vboard/s....php?p=3698306

[cadillac_al]

I always figured it was a marketing gimmick to trick people into thinking they were going to save gas. You don't save hardly any gas and all those front drive parts are designed to last 200k miles anyway. It made Mile Marker a bunch of money but didn't help anybody really save any gas or wear and tear. My GMC with 203 has 170K miles and still has original ball joints and U-joints and gets 11 mpg highway and 10 mpg around town. I don't consider it bad since my Dad's 2013 C10 only gets 17 MPG on the highway.

When I go to back into a trailer on some wet grass or off camber ground I never have to worry if the truck is going to slide because it is always in AWD and ready to work. It will go through plenty of mud effortlessly in AWD. The mud would have to be pretty deep for you to need to lock it in 4WD lock; the same with snow. The greatest transfer case ever built is very under-appreciated and too often de-nutted.

[motornut]

I've got a kit in my 78 not sure what type tho.
I've got manual hubs up front.
Locked in 4X4 with (hubs unlocked)I get no drive threw the case.
4H (hubs unlocked) I just get rear.
I shift it to Lock4X4 with hubs unlocked to lube it.
When I changed the rear U-joints,axle out,had to be Locked in to move the truck

[77K10Silverado]

Do they even still sell the shaft kit anymore? I can't find it unless used. Anyone have a link?

[enaberif]

Shaft is not manufactured anymore. If you want to do the part time kit its slugs and you just pull off the tail housing.

Also there are variations to the NP203 that if you have an older unit you may need a spacer where the newer version does not.