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post #1 of (permalink) Old 04-21-2002, 12:16 PM
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np 203 in 79 GMC

ok, here it is. I pulled my transfer case and am wondering if it has been converted to not all time 4x4. When I turn the input shaft and have the case in High or Low with out the Lock only the main rear output turns. When I put it in HL or LL then both outputs turn. Since the 203 is supposed to be all time 4x4 shouldn't both outputs turn at all times? I understand that there is supposed to be a diff or clutch type device to keep the front and rear from binding when turning in plain H or L when not locked out, but both out puts should turn shouldn't they?

help me please
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post #2 of (permalink) Old 04-21-2002, 01:03 PM
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Re: np 203 in 79 GMC

Did you try turning the front output shaft while not in high lock? If it's trully disengaged, it will turn freely. If it's not it will more than likely turn the rear output shaft due to the differential inside. Just like when you jack the back of the truck up and turn one wheel and other turns opposite direction.

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post #3 of (permalink) Old 04-21-2002, 10:16 PM
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Re: np 203 in 79 GMC

It has been converted. The kit has three knobs that you bolt into the carrier of the case. The case is sort of a third differential. We have a 77 Blazer with the 203 we converted and it acted as you describe. We didn't see any difference in power or milage, but the truck definitly drove differntly with it converted. A much lighter feel.
The 203 is a very stroong and durable case which will last forever. Never could get it to stop leaking between the trans and case.
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post #4 of (permalink) Old 04-22-2002, 10:22 AM
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Re: np 203 in 79 GMC

So with it converted, that means the front output should only turn when in High or Low Lock. It shouldn't matter how fast the input is turning on whether the front output turns or not right?


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post #5 of (permalink) Old 04-22-2002, 11:34 AM
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Re: np 203 in 79 GMC

also if I crack open the case is there a way to visually see the differance?
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