Full Time 4x4 T-case, only turns front shaft! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mr Pops · 02-08-2011, 07:48 PM

I have a 1985 Chevy half ton thats been frankenstined by the previous owner, so I don't know what is stock and what isn't. What I do know is that the transfer case doesn't have a 2wd option. (Military?) Anyway, I tried to move the truck the other day and it wouldn't move when I put it in gear. I looked under the truck and saw the front shaft turning, but not the rear! So I locked the hubs, but it still wouldn't move. (I think one of my hubs isn't locking)
Is this a common problem/symptom? What's broken?

1BadSS · 02-08-2011, 08:18 PM

If it's a full time transfer case (203) with manual front locking hubs and it doesn't have a part time conversion in it. Odds are something is burnt up.

OrrieG · 02-08-2011, 09:43 PM

Not an expert but sounds like the rear output shaft or spider assembly broke. Was it running before? Can you turn the back drive shaft with the transfer in neutral pushing it (no power applied from the transmission). If the front shaft turns then the chain and that engagement is working somewhat. I suspect you will find the back drive line locked up as well.

Blazer1970 · 02-09-2011, 07:46 AM

If it is a full time case (NP203), and you tried to move it with the front hubs unlocked, what you describe is exactly what would happen. The front shaft would spin and the truck would go nowhere. That is normal operation for a 203. An '85 would have come stock with an NP208 though.

Mr Pops · 02-09-2011, 07:55 AM

Quote:

Originally Posted by Blazer1970

If it is a full time case (NP203), and you tried to move it with the front hubs unlocked, what you describe is exactly what would happen. The front shaft would spin and the truck would go nowhere. That is normal operation for a 203. An '85 would have come stock with an NP208 though.

Ok, so it probably boils down to the fact that one of my manual hubs isn't locking.. Come to think of it, I tried to move it last year with the rear driveshaft off, and it wouldn't move then either.

Thanks for all your input guys!

02-08-2011, 07:48 PM	#1
Mr Pops Ridin' Dirty Join Date: Oct 2009 Location: Ardrossan Alberta Canada Posts: 2,193	Full Time 4x4 T-case, only turns front shaft! I have a 1985 Chevy half ton thats been frankenstined by the previous owner, so I don't know what is stock and what isn't. What I do know is that the transfer case doesn't have a 2wd option. (Military?) Anyway, I tried to move the truck the other day and it wouldn't move when I put it in gear. I looked under the truck and saw the front shaft turning, but not the rear! So I locked the hubs, but it still wouldn't move. (I think one of my hubs isn't locking) Is this a common problem/symptom? What's broken? __________________ 1978 C3500 Crewcab (Project) 1979 C2500 Crewcab (Driver/project) 1988 R2500 Crewcab (Driver) 1988 V3500 Crewcab 1988 R2500 Crewcab (Mint, Ex Fire Dept) 1968 Chev Suburban (4x4 conversion) LINK 1970 Chev C20 Suburban (driver/cruiser)LINK 2005 Impala (Incognito vehicle) 2004 Yukon XL Denali (Kid hauler) 1947 Case tractor Facebook Page(1000's of pictures of GM cars and trucks organized into albums) YouTube Channel

02-08-2011, 08:18 PM	#2
1BadSS NOT REALLY BANNED! Join Date: Jul 2004 Location: Shawnee, KS Posts: 1,072	Re: Full Time 4x4 T-case, only turns front shaft! If it's a full time transfer case (203) with manual front locking hubs and it doesn't have a part time conversion in it. Odds are something is burnt up. __________________ 1987 Mustang Coupe - 2.7 Stroker, 78mm turbo, Stainless header, 3" Exh, FMIC, 160lb/hr Injectors, MS3, twin walbro 255's, 34psi. Eating V8's daily. 04 Pontiac GTO 04 Ford Mustang GT 68 C20 LWB stripper truck 73 K5 Cheyenne 76 C20 Sierra Crew SRW 88 K20 Suburban I'm not hammering on metal just to hammer, i'm creating a piece of art.

02-08-2011, 09:43 PM	#3
OrrieG Registered User Join Date: Jun 2006 Location: Idaho Posts: 8,800	Re: Full Time 4x4 T-case, only turns front shaft! Not an expert but sounds like the rear output shaft or spider assembly broke. Was it running before? Can you turn the back drive shaft with the transfer in neutral pushing it (no power applied from the transmission). If the front shaft turns then the chain and that engagement is working somewhat. I suspect you will find the back drive line locked up as well. __________________ 1959 Chevy Short Fleetside w/ 74 4WD drive train (current project) OrrieG Build Thread 1964 Chevelle Malibu w/ 355-350TH (daily driver) Helpful AD and TF Manual Site Old Car Manual Project Last edited by OrrieG; 02-08-2011 at 09:43 PM.

02-09-2011, 07:46 AM	#4
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	Re: Full Time 4x4 T-case, only turns front shaft! If it is a full time case (NP203), and you tried to move it with the front hubs unlocked, what you describe is exactly what would happen. The front shaft would spin and the truck would go nowhere. That is normal operation for a 203. An '85 would have come stock with an NP208 though. __________________ Tim



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