77 4WD Truck

if you've got auto hubs, back up more than the length of the vehicle to disengage them. if you don't and are in 2wd, the front axle won't be recieving any power, but will be driven by the road.

-Bret

IIRC, the '77 didn't have the option of 'autolock' hubs - they were manual lock or just a solid sprag (you couldn't unlock 'em). That doesn't mean that someone didn't add the autolocks later though, but can you describe what the cap on your hubs looks like? Is it silver and flat with 6 bolts around it? Is it silver and flat with no bolts around it? Is it any random color with an I shaped handle in the middle?

Jeremy

Hi Bret, Yea, I tried that, and they still seem to be engaged. I'm thinking maybe they're solid(always on).

Thanks!

Gregg

That's the New Departure 203 chain drive transfer case, pretty much bullet proof as long as you keep it in 2HI when you are on dry pavement,

To maintain thorough lubrication it needs to be exercised ( a mile or so) through it's gears (2HI/4HI/N/2LO/4LO) every month or so. The more you "work" this Transfer Case the slicker it works, don't "use" it at all and you will find the shifter sticks like a bugger.

My '78 Chevy 3/4 ton is full time- no locking hubs, it's sometimes tough to get into 4 wheel and with an Automatic tranny it's fiddly to get back out of

4 wheel. I often put the AutoTranny in Neutral pull the Transfer case shifter into Neutral then turn off and crank the motor whilst pulling the T case shifter into 4HI.(the Auto tranny has enough creep in Neutral to spin the input shaft) and you will feel the dogs drop in to 2HI, careful don't pull it all the way back into 4H. By putting everything into Neutral you are unwinding the driveline just like you would if you backed up to try to pop it out of 4 wheel. I've had mine stick and having gone through several reversing maneuvers to try to kick it out reverted to this restart in Neutral/Neutral mode to finally release the front end.

Once you get the "Knack" you will wonder what anyone is talking about when they say the 203 is cantankerous. Word of warning, don't loan the rig out to anyone that is not familiar with how to work the transfer case, they can do you a lot of driveline damage in 4wheel drive at high speeds on dry pavement.

Friends who have never driven one and "Wonder what this does" can really "Do" your wallet.

Spud, Mountain climbing last weekend in the ice and snow with full jewelry (chains on all four) up to at least 10mph once or twice.

describe

Jeremy,

They're silver, slightly rounded, no bolts. No handle, they're definately not manual. Maybe they are just solid. If this is the case, do I have the shifter opsitions right? Also, can I change these out for manual hubs, or is is best to just leave them?

Thanks!

Gregg

You've got the solid ones - and that means you've got a New Process 203 Full-time Transfer case. Unless it's been converted to part time (Milemarker makes a kit for it), you've got the first "all wheel drive" system! :-) Your shift pattern if it's still a stock NP203 is: lo lock, lo, neutral, hi, hi lock (with lo lock being closest to dashboard, hi lock being closest to seat). You can switch between lock and unlock under load, but to shift from hi to lo or back you need to be stopped and your transmission needs to be in neutral. (even then sometimes it's a bit tricky - i've had to shut off engine and let it spin down before I could get it to catch right)

If you have any more questions, give me a hollar....

Jeremy

Exactly right Jeremy, I had a 77 Silverado shorty HD half-ton with the NP203. In high it would still put "some" power to the front wheels. Not sure about the % split. There was a spider set in the T-case that split power front to back. A solid gear meshed with the spiders to make hi-lock. The major drawback was fuel mileage. I put a Rough Country conversion kit in mine. The kit consisted of a set of hubs and a solid gear to replace the spider set. I went from 10-11 MPG to 14-15.