4X4 no worky - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Tynee · 05-03-2005, 08:18 AM

Buddy's '71 Jimmy... 307 TH350 guessing SM465 Tcase. Don't seem to get any torque at front wheels. Double checked both front hubs locked, tried 4H and 4L. Can pull up against the slightest of bumps, or a curb on the street, rear tires spin, fronts won't pull truck up over curb. Any suggestions where to start trying to doagnose the problem? First time he has ever owned a 4X4, and first time I've had to trouble-shoot one.

Jason915 · 05-03-2005, 01:06 PM

1st off the Tcase is not an SM465, an SM465 is a 4 speed transmission. It prolly has a 205 tcase what I would do it pull the front drive shaft off so you can manually turn the front tcase yoke by hand when tcase is engaged to see if it is actually engaging. this will also allow you to lock the front hubs and manually turn the front axle yoke while the front hubs are locked to see if they are both locking. If one hub is not locking then you will not have front wheel drive power when the t-case is locked. My guess is that the front hubs need to be serviced or replaced. You can also check operation of both front hubs and tcase w/o pulling the front drive shaft but it's much easier to trouble shoot your problem with it removed. When the hubs are both locked and both front tires on the ground you should not be able to continue to turn the front axle yoke if you can turn it freeley then look at the axle shafts and see what one is turning that would point out if there was a hub not locking.

Good luck

Hoods69BadBowTie · 05-03-2005, 01:33 PM

Yeah it probably is a 208 or 205 transfer case. Yes it sounds like one or both of the hubs are not engaging. Has he ever used the 4x4 on the truck? I mean did he just buy it and it started not working or were there any things that led up too it not working? Like noises coming from anything or was it just all of the sudden it does not work.
-Later

Tynee · 05-03-2005, 08:44 PM

Paint me embarrassed. I promise, I know the difference between the transmission and the tcase, just a momentary brain fart. And it is a 205, not a 208 (208 is full-time 4wd, right?).

Anyway, thanks for the input, Jason. These were the things I was planning on working with him on this weekend, or sometime. I just wanted to see if there was something else that was common, but I didn't know about.

72 CustomCamper · 05-03-2005, 11:57 PM

203 is a full time case. the 208 is an aluminium(sp) case used in the 80's...

Chuck

Jason915 · 05-04-2005, 01:15 PM

The 205's is a very tuff T-case and I hardly ever see one that has failed, good luck

drink2mny · 05-04-2005, 02:24 PM

How about spider gears????

Does the front driveshaft turn??

05-03-2005, 08:18 AM	#1
Tynee I miss this truck. Join Date: Dec 2001 Location: Lexington, KY U.S.A. Posts: 2,863	4X4 no worky Buddy's '71 Jimmy... 307 TH350 guessing SM465 Tcase. Don't seem to get any torque at front wheels. Double checked both front hubs locked, tried 4H and 4L. Can pull up against the slightest of bumps, or a curb on the street, rear tires spin, fronts won't pull truck up over curb. Any suggestions where to start trying to doagnose the problem? First time he has ever owned a 4X4, and first time I've had to trouble-shoot one. __________________ '07 GMC Acadia SLT. Sweet ride. '08 Crew Cab Z-71 short bed. Really like this truck A LOT.

05-03-2005, 01:06 PM	#2
Jason915 Registered User Join Date: Jan 2005 Location: Colorado Springs Posts: 693	1st off the Tcase is not an SM465, an SM465 is a 4 speed transmission. It prolly has a 205 tcase what I would do it pull the front drive shaft off so you can manually turn the front tcase yoke by hand when tcase is engaged to see if it is actually engaging. this will also allow you to lock the front hubs and manually turn the front axle yoke while the front hubs are locked to see if they are both locking. If one hub is not locking then you will not have front wheel drive power when the t-case is locked. My guess is that the front hubs need to be serviced or replaced. You can also check operation of both front hubs and tcase w/o pulling the front drive shaft but it's much easier to trouble shoot your problem with it removed. When the hubs are both locked and both front tires on the ground you should not be able to continue to turn the front axle yoke if you can turn it freeley then look at the axle shafts and see what one is turning that would point out if there was a hub not locking. Good luck __________________ 1971 GMC K1500 SWB Fleetside, 4" skyjacker softride and, 14 Bolt FF, HD Dana 44 4.10's 1970 K5 TBI conversion lifted etc SOLD 1968 C20 camper truck SOLD “To ban guns because criminals use them is to tell the innocent and law-abiding that their rights and liberties depend not on their own conduct, but on the conduct of the guilty and the lawless.” Jeff Snyder

05-03-2005, 01:33 PM	#3
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	Yeah it probably is a 208 or 205 transfer case. Yes it sounds like one or both of the hubs are not engaging. Has he ever used the 4x4 on the truck? I mean did he just buy it and it started not working or were there any things that led up too it not working? Like noises coming from anything or was it just all of the sudden it does not work. -Later __________________ HOODS is what I answer too -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!

05-03-2005, 08:44 PM	#4
Tynee I miss this truck. Join Date: Dec 2001 Location: Lexington, KY U.S.A. Posts: 2,863	Paint me embarrassed. I promise, I know the difference between the transmission and the tcase, just a momentary brain fart. And it is a 205, not a 208 (208 is full-time 4wd, right?). Anyway, thanks for the input, Jason. These were the things I was planning on working with him on this weekend, or sometime. I just wanted to see if there was something else that was common, but I didn't know about. __________________ '07 GMC Acadia SLT. Sweet ride. '08 Crew Cab Z-71 short bed. Really like this truck A LOT.

05-03-2005, 11:57 PM	#5
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,368	203 is a full time case. the 208 is an aluminium(sp) case used in the 80's... Chuck __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

05-04-2005, 01:15 PM	#6
Jason915 Registered User Join Date: Jan 2005 Location: Colorado Springs Posts: 693	The 205's is a very tuff T-case and I hardly ever see one that has failed, good luck __________________ 1971 GMC K1500 SWB Fleetside, 4" skyjacker softride and, 14 Bolt FF, HD Dana 44 4.10's 1970 K5 TBI conversion lifted etc SOLD 1968 C20 camper truck SOLD “To ban guns because criminals use them is to tell the innocent and law-abiding that their rights and liberties depend not on their own conduct, but on the conduct of the guilty and the lawless.” Jeff Snyder

05-04-2005, 02:24 PM	#7
drink2mny Registered User Join Date: Jun 2003 Location: spokane wa Posts: 2,189	How about spider gears???? Does the front driveshaft turn?? __________________ Support The Board

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