4WD Class 101 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

3quartertime · 03-05-2005, 12:36 PM

Got a problem. Either I don't know how to engage the 4WD in my truck or it doesn't work. Truck is a 71 K20 with spicer lock-outs. Don't know the type transfer case or front end.

I spin the lock-out hubs to lock and with the truck in neutral I try to engage 4-lo. Only back tires spin. Tried 4-hi same thing. Can't turn front drive shaft with hand in either. But in 2-hi it turns by hand. So I'm thinking the tranfer case is working, thou I haven't actually seen the driveshaft spin while the truck is moving.

Sooo,,, either I don't know how to engage 4WD in the truck ( Which I would be grateful if someone could school me!!!) or my lock-outs aren't working. Or a little of both!!!

If it's the lock-outs what is the most likely problem?

Thanks for any help...

**JIMs70GMC** · 03-05-2005, 02:13 PM

If your manual hubs are not working and the transfer case is in 4wd hi or low the front driveshaft should still turn. Since when the transfer case is in 4wd hi or low you can not turn the driveshaft(it's locked to the rear) then the transfer case is working.

Quote:

with the truck in neutral I try to engage 4-lo. Only back tires spin

is that the transfer case or tranny? If you have the both hubs locked and the transfer case in 2hi, the front drive shaft should not turn as the tires would want to turn, if you can turn it I'd say your hubs(at least one) is bad.

Americanrider · 03-05-2005, 07:51 PM

Which type of transfer case are you running? I would look into the transfer shifter to make sure it's hooked up & working properly, might be an easy fix.

Hoods69BadBowTie · 03-05-2005, 10:06 PM

Yeah, sounds like its engaging but not working. Might be one of the hubs or something easy with the transfer case, hopefully.
-Later

Destructo · 03-05-2005, 10:09 PM

I had a similar problem, hub didn't have enough grease in it and wouldn't operate freely and it wouldn't lock.

Take the hubs apart, clean them up and re-grease them well and put them back in.

Blazer1970 · 03-06-2005, 09:03 AM

Yup, one or both hubs are not locking.

ZOOMY · 03-07-2005, 07:29 AM

What Blazer or Destructo said, or a u-joint in the axle-shaft is torn right out. (I just did that last fall).

**JIMs70GMC** · 03-08-2005, 08:36 PM

Whatcha find out?

3quartertime · 03-10-2005, 12:11 AM

Quote:

Originally Posted by JIMs70GMC

Whatcha find out?

Nothing yet!!!

It's been cold in these parts and I work outside. No motivation to crawl around under the work truck after being cold all day unless whatever is broke makes the truck not go...

I'm waiting for a better day to try all the suggestions.

I'll report back!!!

Thanks.

Blue_71 · 03-12-2005, 01:05 AM

when you hit lock, can you turn the hubs any further? i think my truck has 1/4 turn hubs but i think ive heard of some that take a pretty far turn to get them locked... they should hit lock and not be able to go any further

nu2-72 · 03-12-2005, 10:43 AM

First, you will have large spicer hubs if they are original. The knobs are supposed to read "Spicer" with an arrow pointing position. If the name plate is gone, just remember that it runs straight with the center raised part of the knob. The arrow or straight line should line up with "Free' or "Lock" and go no further in either direction. About 1/4 turn. If it turns further your tab on the knob is broken. This will not stop the lockouts from working but will turn them slightly too far one way or the other. The knob will still stop each direction but just a little too far.
Next, if the knob will rotate 360 degrees you have broken ears and the pin is no longer stopping rotation. The knob has a pin that rotates a metal sleeve inside the assembly. This sleeve is spiral cut to rotate out and apply pressure to the clutch gear pack. If it does stop in the rotation suggesting the that the ears and pin are OK, then you may have too stiff of grease or broken internal springs. The springs push the gear pack out to disengage but if broken may prevent engagement.
Put the truck on stands. Engage the lockouts. Put the transfer case in neutral. Turn the front driveshaft. The driveshaft and wheels should be locked together and the wheels will turn. Transfer case is disengaged.
Take lockouts out. Place the transfer case in high or low. Front and rear should now be together and rear will turn by rotating the front shaft. If not, you are not engaged in the transfer case. Pull the linkage to make sure it is engaged or remove the linkage and make darn sure that you feel it lock in by hand.
May just be adjustment of the shifter.
If high works but no low, try adjustment. If neither high or low work. Troubles.
There is a thread here about "How To" . Look at the pics and you can see the ears and pin hole and the tab.
Good luck.

nu2-72 · 03-12-2005, 10:53 AM

See if this helps. Hope it is clear.

IBAPIGFARMER · 02-20-2008, 07:37 AM

Does anyone know if you can still get a rebuild kit for the original spicer hubs?
(I.E. Yellow knob,pin,spring,etc.) or do you have to go to a replacement hub?

03-05-2005, 12:36 PM	#1
3quartertime My Mistress the Sea Join Date: Feb 2005 Location: Bradenton, FL. Posts: 412	4WD Class 101 Got a problem. Either I don't know how to engage the 4WD in my truck or it doesn't work. Truck is a 71 K20 with spicer lock-outs. Don't know the type transfer case or front end. I spin the lock-out hubs to lock and with the truck in neutral I try to engage 4-lo. Only back tires spin. Tried 4-hi same thing. Can't turn front drive shaft with hand in either. But in 2-hi it turns by hand. So I'm thinking the tranfer case is working, thou I haven't actually seen the driveshaft spin while the truck is moving. Sooo,,, either I don't know how to engage 4WD in the truck ( Which I would be grateful if someone could school me!!!) or my lock-outs aren't working. Or a little of both!!! If it's the lock-outs what is the most likely problem? Thanks for any help...

03-05-2005, 10:06 PM	#4
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	Yeah, sounds like its engaging but not working. Might be one of the hubs or something easy with the transfer case, hopefully. -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!!

03-05-2005, 10:09 PM	#5
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	I had a similar problem, hub didn't have enough grease in it and wouldn't operate freely and it wouldn't lock. Take the hubs apart, clean them up and re-grease them well and put them back in. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

03-06-2005, 09:03 AM	#6
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,507	Yup, one or both hubs are not locking. __________________ Tim

03-08-2005, 08:36 PM	#8
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	Whatcha find out? __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

03-05-2005, 07:51 PM	#3
Americanrider Registered User Join Date: Dec 2004 Location: NW, WA. Posts: 1,421	Which type of transfer case are you running? I would look into the transfer shifter to make sure it's hooked up & working properly, might be an easy fix.

03-07-2005, 07:29 AM	#7
ZOOMY Senior Member Join Date: Feb 2003 Location: WIS Posts: 1,752	What Blazer or Destructo said, or a u-joint in the axle-shaft is torn right out. (I just did that last fall).

03-12-2005, 10:43 AM	#11
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	First, you will have large spicer hubs if they are original. The knobs are supposed to read "Spicer" with an arrow pointing position. If the name plate is gone, just remember that it runs straight with the center raised part of the knob. The arrow or straight line should line up with "Free' or "Lock" and go no further in either direction. About 1/4 turn. If it turns further your tab on the knob is broken. This will not stop the lockouts from working but will turn them slightly too far one way or the other. The knob will still stop each direction but just a little too far. Next, if the knob will rotate 360 degrees you have broken ears and the pin is no longer stopping rotation. The knob has a pin that rotates a metal sleeve inside the assembly. This sleeve is spiral cut to rotate out and apply pressure to the clutch gear pack. If it does stop in the rotation suggesting the that the ears and pin are OK, then you may have too stiff of grease or broken internal springs. The springs push the gear pack out to disengage but if broken may prevent engagement. Put the truck on stands. Engage the lockouts. Put the transfer case in neutral. Turn the front driveshaft. The driveshaft and wheels should be locked together and the wheels will turn. Transfer case is disengaged. Take lockouts out. Place the transfer case in high or low. Front and rear should now be together and rear will turn by rotating the front shaft. If not, you are not engaged in the transfer case. Pull the linkage to make sure it is engaged or remove the linkage and make darn sure that you feel it lock in by hand. May just be adjustment of the shifter. If high works but no low, try adjustment. If neither high or low work. Troubles. There is a thread here about "How To" . Look at the pics and you can see the ears and pin hole and the tab. Good luck. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

03-12-2005, 10:53 AM	#12
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	See if this helps. Hope it is clear. Attached Images __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

02-20-2008, 07:37 AM	#13
IBAPIGFARMER Registered User Join Date: Jan 2008 Location: Holt,Mo Posts: 30	Re: 4WD Class 101 Does anyone know if you can still get a rebuild kit for the original spicer hubs? (I.E. Yellow knob,pin,spring,etc.) or do you have to go to a replacement hub? __________________



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