Transfer case question

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Can you guys please explain to me how my transfer case works. 78 K10 all stock as far as I know. Previous owner told me they had It modified so it wasn't full time 4 wheel drive. It has locking front hubs and the shifter has 4 low, lock, 4 high, lock. I drive it with the shifter in the N position. They said to put it in 4x4 I lock in the hubs and then shift the transfer case into 4 hi or low. Also what's the difference between 4 hi or low and lock?
 

Turbo4whl

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Keep in mind the NP203 transfer case was designed before the first fuel shortage and gasoline was less than 40 cents a gallon. There is straight drive through, 1:1 in high gear and low gear is 2:1.

Originally before your 203 was modified the front axle would always drive in the unlocked position and the rear axle would drive though a differential gear set. When shifted to the high or low lock the differential would be locked out and now both axles are driving fully.

Since there were many aftermarket kits to change this to a part time 4 wheel drive you may or may not have your front drive shaft spinning all the time.
 

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Can you guys please explain to me how my transfer case works. 78 K10 all stock as far as I know. Previous owner told me they had It modified so it wasn't full time 4 wheel drive. It has locking front hubs and the shifter has 4 low, lock, 4 high, lock. I drive it with the shifter in the N position. They said to put it in 4x4 I lock in the hubs and then shift the transfer case into 4 hi or low. Also what's the difference between 4 hi or low and lock?

Your truck was full time 4wd, which meant that you were always in 4wd.

The Loc position, either low or high, eliminated the differential action that allowed the use of 4wd on the street.

With it converted to part time, I guess the 4 Low and High give you 2wd Low and High, o and the Loc positions are what gives you 4wd.

The Low range is just that - a roughly 2:1 gear reduction over 4wd high, which is 1:1.

The shifter in neutral seems weird to me as originally that was to run a power take off if one was installed.

Maybe the shifter is not aligned correctly with the plate on the transmission hump, so Neutral as shown is really 4 high, which for you now is 2wd.
 

dvdswan

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1. Your shifter needs adjustment. The vehicle would not move with the shifter in N (neutral).

2. 4WD is engage when the shifter is in the Lock position.

The idea of the full-time transfer case was so the vehicle would have "traction" all the time. If the rear wheels started to spin power would transfer to the front wheels to maintain traction.
 

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N on the transfer case was also used for Towing the vehicle so you didn't have to pull your driveshaft or driveshafts. Sometimes used for being winched out too. Put the T case in N and both driveshafts are free spinning at the transfer case end and not holding the vehicle whatsoever. That was important to the NP203 because your front axles were locked in permanent until they did the Part Time conversion and put the manual lockout hubs on the front hubs.
 

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AuroraGirl

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Is it preferable to keep these full time 4wd that way or to make them part time? My dad has a 75 K25 and he had to pull the hub... err... cap... because he said the U joints were binding and causing issues. Im not sure if he understands properly, it seems strange to me. But something will have to be fixed, is it worth to fix to what it was or converted?
 

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as stated above, full time 4wd ate more gas then being able to put the truck in 2wd. also a reduction in parts wear.

so part time 4wd has benefits.

the 'lo' range selector, as stated above, basically drops your traveling speed and raises your engine rpm at given speed.

this allows you more 'pulling' power out of a ditch maybe or similar.
also handy for crawling up a long, snow covered hill, etc.

'n' really should disconnect the transmission from the driveshafts.

my 2005 dodge ram tows with all 4 wheels on the ground by putting the transfer case in 'n' and the auto trans in park.
(this keeps the transmission from moving around 'dry' without the fluid being circulated)

hopefully, that puts in 'layman's' terms what the hi/lo stuff does.
 

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Is it preferable to keep these full time 4wd that way or to make them part time? My dad has a 75 K25 and he had to pull the hub... err... cap... because he said the U joints were binding and causing issues. Im not sure if he understands properly, it seems strange to me. But something will have to be fixed, is it worth to fix to what it was or converted?

To summarize, part time is more efficient.
My guess is your dad removed the inner axles to disconnect the hub from the wheels. But it is also possible to remove the “hubs” to disconnect it too. But you’d need some way to cover the bearings to keep them moist.
 

eskimomann209

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Better choice Is manual locking hubs and keep them unlocked. This will disconnect the diff from the wheels but the t case still spins and that is still inefficient
 

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How does one convert the system to manual locking hubs?
 

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How does one convert the system to manual locking hubs?
There is a part time kit to put in the 203 t case to enable 2wd.But the experts I talked to back in the day said the kit will cause some wear on tge 203 t case.My k10 is fulltime 4wd and I figured not enough improved fuel economy to warrant the cost of conversion.
 

eskimomann209

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You cant just mount lockable hubs on a fulltime 4wd hub and have 2wd.
Yeah you’re right. It’ll then send all the power to that front, least resistance, axle.
:emotions33:




:drink_nl:
 

Goldie Driver

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There is a part time kit to put in the 203 t case to enable 2wd.But the experts I talked to back in the day said the kit will cause some wear on tge 203 t case.My k10 is fulltime 4wd and I figured not enough improved fuel economy to warrant the cost of conversion.

The 77 and 2 79 RamChargers I had were full time as well as the 77 Suburban.

I distinctly remember getting 9 - 10 highway on the 90 mile highway drive to school in the RamChargers, probably a bit less in the Sub.

Yes, you do save wear and tear on the front end, but full time pulled you around corners like a sports car, gave wonderful off the line launches, and a sense of ease in crappy weather or if you just decided to drive offroad on a lark.

If Goldie was full time I probably would not jack with her - cheaper and lazier route.

But, that's my style...

:)
 

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