1978 Chevy 4x4 1/2 ton

I believe you can put manual lock out hubs on a 1978 Chevy.

Brian

There is probably nothing wrong with the transfer case- the New Process 203s are just a REAL BITCH to shift and the linkage rods inside can be stripped if you really force the shifter.

When I first bought my truck 10 years ago I thought mine was frapped too, a logger friend hopped in and it actually shifted like silk for him, whereas I hadn't been able to get to square one with it. Admitted I still find occasionally mine will lock up in 4WD and it can be a frustrating experience to release it.

I replaced my NP203 once with a Lo Miles rebuild,( 3 man job to lift and bolt in), it was exactly the same to shift as the original, I had wasted my time and money.

If the driveline is stock it's probably a full time 4WD (No manual Warn hubs on front wheels) and will cost you about 1-2MPG over a selective part time 4WD (with manual or automatic hubs) to run.

First of all, lube up the exposed linkage on the upper right side of the transfer case, check to see that the linkage is adjusted correctly and that the plastic bushings are not worn through, there are two holes in the shifter linkage frame that a drill bit should slide through frame-linkage and other side of frame when adjusted correctly in neutral 2WD

Once that accomplished, FIDDLE with the shifter while you reverse at least

50 ft., foreword a similar distance, all the time the vehicle is moving you are trying to gently bump it out of 4WD, when the driveline torque is eventually eliminated it will POP out. My 78 chevy3/4 ton (same transfer case) has always been FUN, sometimes I speedshift from HI to LO 2WD sometimes I have turn the engine off and crank the starter to get it into HI or LO, sometimes I have to HOLD the shifter into 4WD-LO over some washboard before it will stay in 4.

You can remove the front driveshaft and leave it in 4WD,that will work, but if you put it into 2WD the planetary gears in the transfer case are unlocked and the front shaft stub only will spin, and the rear driveshaft will not turn.

In order to convert the New Process 203 to part time 4WD you have to buy a kit for the transfer case differential and install the locking hubs on the front axle. Warning though, with the NP 203 converted to part time it doesn't get full lubrication and MUST be run once every 1000mi or so in 4WD to give ALL the bearings a good splash of fresh oil.

Remember keep fiddling and fiddling with the old bugger and it will probably surprise you by complying. Those NP203s were used by Ford, GM, and Chrysler, they are lying around allover the country, worth about $50.00 - if you can get that much, (do you want one?) and you probably know someone (farmer, hunter, logger, etc.) who knows these

200lb cast iron beauties well enough to give it a good "talking to", after that, you just practice till you figure out what it likes and doesn't like to do.

If it's truly locked up you might try jacking up one wheel, get someone to apply shifter pressure while you rock the wheel back and forth, there may be water inside and the dogs could be rusted to the shaft.

Let us hear how you make out. Spud

More info:

You can find a lot of info by entering "NP203,NP_203, or New_Process_203" into Google Web, then Images, then Groups.

Spud

You can install a part-time kit in the transfer case and shorten it's lifespan or swap it out for a NP205. The 203 is a full-time case which spins the front shaft constantly.

I checked on what you explained to do to get it out of 4x4, but the transfer case just doesnt have 2HI in it, the selector knob only reads 4h-N-4L, and it only clicks three times starting with 4h then back to the seat for 4Lo this truck is a gas drinker, I think it gets about 40miles to half a tank of gas.

>

Best way to do it is to drop the NP-203 transfer case and find an NP-205 to put in it. Then go buy a set of lock-out hubs and install them on the front axle.

Tony