Question on auto hubs - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ScottH** · 12-03-2006, 10:44 AM

Gonna look at a 79 K10 soon that has front auto hubs. Never owned a 4x4 before and heard some folks saying these are prone to problems if not maintained properly. Can anyone tell me what to look for when I check out this truck?

Any info or suggestions are appreciated.

Thanks

msgross · 12-03-2006, 07:35 PM

you can replace the autos with a set of manual hubs. I just happen to have a nice set for sale too! Let me know if interested....

my first vehicle was a 79 Blazer with auto hubs, not bad except the gas mileage, you should pick up a few MPG's with a set of manuals installed.

LONGHAIR · 12-04-2006, 08:34 PM

Are you sure that they are auto locking hubs? Those would not have been on a '79. The automatics didn't come out until '81 or '82 on trucks equipped with a "new" aluminum transfer case (NP208). Your '79 should have had the big cast iron NP203 transfer case. That was a "full-time" four wheel drive unit. They had drive flanges under a small cad plated cap that was hammered on. The automatic hubs are held on with 5 torx headed bolts.

Either one can be replaced by manual locking hubs. The full-time case (NP203) needs to have a conversion kit installed if the flanges are removed.
If this truck has been modified/up-dated to the newer NP208 case, all that is required are the manual hubs themselves. The automatic locking hubs don't have the greatest reputation, especially in cold weather, so replacing them with manuals is not a bad idea.

All of this is assuming that you have an automatic transmission...if it has a 4 speed, the transfer case is different. A 4 speed truck would have an NP205 and manual hubs to begin with.

**ScottH** · 12-04-2006, 08:52 PM

Longhair, you are absolutely correct, they are full-time hubs. As a newbie to 4x4s I'm learning. Can you tell me what is involved (basically) to swap over to manual? Any info is really appreciated.

Thanks for the help guys.

Elsie72 · 12-04-2006, 10:49 PM

The thing I don't like about auto hubs is that when you go from Drive to Reverse, the hubs unlock, then re-lock. Some times that's fine, but lots of times, you really need something that's locked when you change directions.

msgross · 12-04-2006, 11:19 PM

Here are the pics of what I have. I am going to keep one of the sets but I do know that they are both in good shape. They run $70-$80 new for these types. I am not sure but your auto hubs will need a conversion kit. Mile-markers website says that auto hubs need a conversion kit and full-time 4WD vehicles need a transkfer case kit, not sure on the hubs though.

**ScottH** · 12-04-2006, 11:31 PM

Mike, thanks for the pics. Let me see if someone can help me out with what is needed to convert the full-time to manual.

Scott

msgross · 12-04-2006, 11:32 PM

Here is the MM website, these aren't going anywhere soon so no hurry on my end. I still don't know which one's I want...

http://www.milemarker.com/4x2conversion.html

12-03-2006, 10:44 AM	#1
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Question on auto hubs Gonna look at a 79 K10 soon that has front auto hubs. Never owned a 4x4 before and heard some folks saying these are prone to problems if not maintained properly. Can anyone tell me what to look for when I check out this truck? Any info or suggestions are appreciated. Thanks

12-03-2006, 07:35 PM	#2
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Question on auto hubs you can replace the autos with a set of manual hubs. I just happen to have a nice set for sale too! Let me know if interested.... my first vehicle was a 79 Blazer with auto hubs, not bad except the gas mileage, you should pick up a few MPG's with a set of manuals installed.

12-04-2006, 08:34 PM	#3
LONGHAIR just can't cover up my redneck Join Date: May 2004 Location: Columbus OH Posts: 11,414	Re: Question on auto hubs Are you sure that they are auto locking hubs? Those would not have been on a '79. The automatics didn't come out until '81 or '82 on trucks equipped with a "new" aluminum transfer case (NP208). Your '79 should have had the big cast iron NP203 transfer case. That was a "full-time" four wheel drive unit. They had drive flanges under a small cad plated cap that was hammered on. The automatic hubs are held on with 5 torx headed bolts. Either one can be replaced by manual locking hubs. The full-time case (NP203) needs to have a conversion kit installed if the flanges are removed. If this truck has been modified/up-dated to the newer NP208 case, all that is required are the manual hubs themselves. The automatic locking hubs don't have the greatest reputation, especially in cold weather, so replacing them with manuals is not a bad idea. All of this is assuming that you have an automatic transmission...if it has a 4 speed, the transfer case is different. A 4 speed truck would have an NP205 and manual hubs to begin with.

12-04-2006, 08:52 PM	#4
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Re: Question on auto hubs Longhair, you are absolutely correct, they are full-time hubs. As a newbie to 4x4s I'm learning. Can you tell me what is involved (basically) to swap over to manual? Any info is really appreciated. Thanks for the help guys.

12-04-2006, 10:49 PM	#5
Elsie72 Chinook Arch Join Date: Feb 2005 Location: High River, Alberta, Canada Posts: 218	Re: Question on auto hubs The thing I don't like about auto hubs is that when you go from Drive to Reverse, the hubs unlock, then re-lock. Some times that's fine, but lots of times, you really need something that's locked when you change directions. __________________ 1972 GMC 1500 Custom - Bought used by Grandpa in '74, currently back on the road after a long hiatus. Elsie's truck 2.5" dual exhaust with Hooker Aero Chambers Holley 670 Street Avenger Edelbrock Performer RPM on GMPP 290HP 350 ECE drop 3.5/5

12-04-2006, 11:19 PM	#6
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Question on auto hubs Here are the pics of what I have. I am going to keep one of the sets but I do know that they are both in good shape. They run $70-$80 new for these types. I am not sure but your auto hubs will need a conversion kit. Mile-markers website says that auto hubs need a conversion kit and full-time 4WD vehicles need a transkfer case kit, not sure on the hubs though. Attached Images Last edited by msgross; 12-04-2006 at 11:27 PM.

12-04-2006, 11:31 PM	#7
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,190	Re: Question on auto hubs Mike, thanks for the pics. Let me see if someone can help me out with what is needed to convert the full-time to manual. Scott

12-04-2006, 11:32 PM	#8
msgross Registered User Join Date: Jul 2006 Location: Central PA Posts: 12,201	Re: Question on auto hubs Here is the MM website, these aren't going anywhere soon so no hurry on my end. I still don't know which one's I want... http://www.milemarker.com/4x2conversion.html Last edited by msgross; 12-04-2006 at 11:33 PM.

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