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so i installed the manual hubs yesterday...

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CoorsLightCoupe

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and now noticed that my rear driveshaft doesnt engage from the TC. i wonder how long ive been driving around a front wheel drive Jimmy?

im still pretty new to the whole transfer case thingy, but i think the one i've got is the np203, right? the full-time 4wd one installed in most of these trucks... will a np205 bolt right in in place of this one?


it's a 79 jimmy, BTW
 
Might be easy just to drop a 203 from the junk yard back in. Not sure if they interchange, do a search on here or keep asking, someone knows
 
Assuming you have a 203, did you install a part-time kit in the t-case? If not, you will have to put it in Hi-Loc to drive. Without a part-time kit installed you haven't accomplished much due to the way the 203 works.
 
sounds like you dont have the part time kit installed and now with the front hubs able to unlock you rear shaft wont spin either. get the part time kit, or put it in loc and drive. in loc you'll still be spinning the front shaft though.
 
i havent touched the T-case. all i did was get the hub conversion from CSK and install them. t-case only has 4loc, neutral, and 4low. in neutral, nothing happens. in 4-lock is when it's always been. 4low works just fine too. in 4lock it only trns the front driveshaft

**ok, i went out and put it on jackstands, tried every possible gear combo...

hubs locked, tcase in 4lock: spins all 4 wheels just fine
hubs unlocked, t-case in 4lock: barely spins the rear wheels. front shaft still hauling ass, making some nice whining noise
t-case in neutral doesnt do anything, no matter what i do
4-low is repeated results as above.


so what is this part-time kit for the t-case? where do i get it and how hard is it to install?
 
Last edited:
CoorsLightCoupe said:
i havent touched the T-case. all i did was get the hub conversion from CSK and install them. t-case only has 4loc, neutral, and 4low. in neutral, nothing happens. in 4-lock is when it's always been. 4low works just fine too. in 4lock it only trns the front driveshaft

**ok, i went out and put it on jackstands, tried every possible gear combo...

hubs locked, tcase in 4lock: spins all 4 wheels just fine
hubs unlocked, t-case in 4lock: barely spins the rear wheels. front shaft still hauling ass, making some nice whining noise
t-case in neutral doesnt do anything, no matter what i do
4-low is repeated results as above.


so what is this part-time kit for the t-case? where do i get it and how hard is it to install?
Click to expand...

In 4-lock, with the hubs locked, it should spin all 4 just fine.

In 4-lock, with the hubs unlocked, both driveshafts should spin the same speed but only the rear tires should be moving.

4-low lock should do the same, but at half the speed.



The whining noise could be lots of things, but almost definitely unrelated.

The problem you initially posted probably isn't a problem. Unlock the hubs, put it in 4-lock (or 4 hi-lock, whatever it says) and drive it. I bet it drives fine.
 
it doesnt move at all with the hubs unlocked. the axles spin when it s on jackstands, but nowhere near as fast as they do when the hubs are locked. WTF?
 
You must put the t-case into either hi-loc or low-loc in order for the truck to move if you haven't taken the t-case apart and installed the part time kit.
 
Pretty much. The manual hubs do allow the front wheels to be disengaged though instead of having power to them all the time.
 
Let me try to explain how this works. The 203 t-case has a differential in it. It is the same as having a rear differential on your truck with an open rear axle meaning no locking differential. Take a jack and jack one wheel off the ground and start the truck and put it in gear and the rear shaft will spin and the tire that is off the ground will spin but the truck won't move. This is the same way the 203 t-case works but now instead of talking about wheel we're talking about front and rear axles. If the front hubs are unlocked then all the power is going to go to the front axle but since the hubs are unlocked the truck won't move.
 
Your Tcase has a differential inside it. It is how GM was able to run a full time 4wd on the pavement. It allows the front and rear shafts spin at different speeds rather than bind the gears and chain in the case.

Much like an open differential the power will go to the shaft with the least traction (or resistance if you will). With the front hubs unlocked there will be zero traction so the front shaft will get all of the power and the rear shaft will not turn. Putting the Tcase in 4-loc makes the differential like a spool and splits the power equally between front and rear shafts.

Put the Tcase in 4-loc or 4-lowloc and try it with no jackstands and I bet it will drive just fine.

Dik
 
4X4HIGH said:
Let me try to explain how this works. The 203 t-case has a differential in it. It is the same as having a rear differential on your truck with an open rear axle meaning no locking differential. Take a jack and jack one wheel off the ground and start the truck and put it in gear and the rear shaft will spin and the tire that is off the ground will spin but the truck won't move. This is the same way the 203 t-case works but now instead of talking about wheel we're talking about front and rear axles. If the front hubs are unlocked then all the power is going to go to the front axle but since the hubs are unlocked the truck won't move.
Click to expand...

Damn beat me to it:doah:

Dik
 
CoorsLightCoupe said:
super. this thing's a bigger pain in the ass than my mustang.
Click to expand...

Just put it in 4-loc or 4-hiloc what ever the shifter says and drive it. It will be fine. I drive around with my 208 in 4wd and the hubs unlocked to spin the chain every so often and it hasn't hurt anything.

Dik
 
that's just it though. i HAVE to drive it in 4lock anyway, but with the hubs unlocked, it doesnt move. all it does is spin the front driveshaft.
 
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