NP203 question

[Desertryder]

Hey gang, on my '76 GMC k15 I was wondering if I put a np203 w/o the
Mile Marker kit in the tcase, can I leave the Mile Marker lock out hubs
on the front wheels and just leave the hubs locked in all the time or do I need to
remove the lock outs? Basically I want to know if it will work w/o removing
the lock out hubs.

[LONGHAIR]

Yes it will work with the hubs locked-in.

[Benelli]

With the hubs un-locked in the "free" posistion, the driveshaft will be spinning (front and rear) but it will not be putting the power to the ground. I think. I also believe this is very hard on the transfer-case. Am I right?

Until you actually part-time the t-case (if you plan to) I'd just leave 'em locked in and let the good times roll.

[Desertryder]

Thanks, keep the info coming. Always feeding on good advice.

[Tony@AirRideTech]

not to be a nay sayer but what is the point of keeping a 203 in there with manual lockouts, without the planetary grear change-out? If it is because you have grenaded a set of factory automatics, I would go ahead and change it all over. better mileage and the truck will drive better. If it were me, I would swap out for a 208 / 241 style case. Has a better low range and if you keep them serviced they are excellent cases.

[LONGHAIR]

Originally Posted by Tony@AirRideTech

If it is because you have grenaded a set of factory automatics, I would go ahead and change it all over.

While I would totally agree with doing the entire installation....automatic hubs did not come with NP203 transfer cases. They had solid slugs that were splined inside and out.....automatics came with NP208 'cases starting in the early 80's.

[2tons of fun]

Originally Posted by Benelli

With the hubs un-locked in the "free" posistion, the driveshaft will be spinning (front and rear) but it will not be putting the power to the ground. I think. I also believe this is very hard on the transfer-case. Am I right?

Until you actually part-time the t-case (if you plan to) I'd just leave 'em locked in and let the good times roll.

why would the rear shaft spin?

only the front shaft will spin because the shafts are disconnected, but you wont move.

[Damien]

Originally Posted by 2tons of fun

why would the rear shaft spin?

only the front shaft will spin because the shafts are disconnected, but you wont move.

The np203 is a full time case, so the front and rear drive shafts are always engaged, unless the transfer case is in neutral. Then neither will spin.

[paps69]

The 203 is full time but it has a set of spider gears in the rear of the case to transfer back and forth to front and rear when in the 2H or 2L position. Therefore with the hubs unlocked it takes the path of least resistance to the front driveshaft and leaves you sitting still. I think I explained it right??

[Tony@AirRideTech]

Originally Posted by paps69

The 203 is full time but it has a set of spider gears in the rear of the case to transfer back and forth to front and rear when in the 2H or 2L position. Therefore with the hubs unlocked it takes the path of least resistance to the front driveshaft and leaves you sitting still. I think I explained it right??

Good explanation....... NP203= Boat anchor

[joe231]

yeah, basically it is another open differential between the front and rear drive shafts.

Originally Posted by 2tons of fun

why would the rear shaft spin?

only the front shaft will spin because the shafts are disconnected, but you wont move.

correct

Originally Posted by Damien

The np203 is a full time case, so the front and rear drive shafts are always engaged, unless the transfer case is in neutral. Then neither will spin.

with the manual hubs on the front unlocked, the front shaft will spin and the rear will do nothing, just like in an open diff with one tire off the ground.

[paps69]

Originally Posted by Tony@AirRideTech

Good explanation....... NP203= Boat anchor

Depending on what you use the truck for. I have one in a 78 3/4 ton that has never been converted. I use it around the farm, no highway driving to speak of, and I love it. 95% of the time The full time does good enough I don't even shift into 4wd. Otherwise you are right.

[2tons of fun]

Originally Posted by Damien

The np203 is a full time case, so the front and rear drive shafts are always engaged, unless the transfer case is in neutral. Then neither will spin.

yes it its, but with the front hubs unlocked all the power will go to the front shaft because it is free and the rear shaft is locked. just like a onpe diff, one whheel spins and the other stays put because it has the traction.

[Damien]

Apparently I miss read something. My Blazer still has the full time np203, and I've never had a problem with it. I like it. Mileage sucks, but I drove an '86 Sub with a np208 that got the same mileage.

[tonyscustomrides]

my 77 has the same t-case. i took out the front left gear thats in the hub, it goes into 2wd. BUT you have to pull the lever all the way back into 4loc or else it does nothing. and as far as milage, it makes NO difference, believe me

[Benelli]

I gained about 1.5-2 MPG when I part-timed and put hubs into mine.

Of course, it depends on how and where you drive. I think if your constantly gunning or tossing mud around then you're not going to notice any difference in mileage.