Shift pattern - converted 203 transfer case

[jdemaris]

I recently got a 78 K5 Blazer with a 203 full-time 4WD transfer case - but it also has free wheeling hubs. So, I assume it's had a full-time to part-time kit put into at some time. I know nothing about these transfercases either way. I've got twenty 4WD trucks, but they are all part-time 4WD - and my GMs are all 205s, 208s, or 241s - except this one.

So, I'm trying to figure out what the different positions are - and would they have changed if a conversion kit was put in? I know it used to have a full time 4WD position, a locked 4WD positon, low-range, etc. It seems right now, that if I push it all the way forward it feels like it's in 4WD low -but I haven't tried in the dirt or snow yet - I'm in the process of putting a plow on it.

 

[dremu]

I recently got a 78 K5 Blazer with a 203 full-time 4WD transfer case - but it also has free wheeling hubs. So, I assume it's had a full-time to part-time kit put into at some time. I know nothing about these transfercases either way. I've got twenty 4WD trucks, but they are all part-time 4WD - and my GMs are all 205s, 208s, or 241s - except this one.

So, I'm trying to figure out what the different positions are - and would they have changed if a conversion kit was put in? I know it used to have a full time 4WD position, a locked 4WD positon, low-range, etc. It seems right now, that if I push it all the way forward it feels like it's in 4WD low -but I haven't tried in the dirt or snow yet - I'm in the process of putting a plow on it.

Stock '203 is...

L Loc (forward)
L
N
H
H Loc (towards your leg)

Loc meaning the center differential is locked, i.e. the front and rear spin at the same speed. Great for snow or loose rock, gravel ... bad for pavement. This is just like your existing part-time cases. When unlocked (regular "L" or "H") the center diff runs full-time, giving some power to all four corners, but with a differential in the center.

With a part-time kit, it changes to

4Lo
2Lo
N
2Hi
4Hi

The kit changes the locking mechanism to engage the front output (or not). I only ever used 4LO (all the way forward) and 2HI (one click from the back.) Now I have a triple-stick Doubler

Manual hubs do not guarantee the existence of a part-time kit. I'd jack up both ends and see if the front drive shaft turns in the various settings.

HTH.

-- A

 

[thedrip]

With the part time kit, the shift pattern is actually

4 Low
2 Low
Neutral
2 High
4 High

If theres just hubs, and no part time kit, shift pattern depends on if the hubs are locked. If they're locked in, its just like stock, if they're open its something like

2 Low
Neutral - hurting the tcase
Neutral
Neutral - hurting the tcase
2 High

 

[dremu]

Crap. Can you tell I was serious about only ever using 4Lo/2Hi ...

Thanks!

-- A

 

[thedrip]

I spend more time in 2L that anything else. Truck doesn't see much street, and with a welded rear, it'd 2wheel through most trails around here. Just grab 4L if I'm about to try something gnarly.