Locking diff??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

CRRoy71 · 03-13-2003, 01:18 AM

I was looking at my little sticker in the glove box with all of the options that came with my truck, and noticed that there was an added option Locking differential.
Does this mean front only, or front and rear. How can I tell, and how good is the factory locking diff?

1969 GMC · 03-13-2003, 02:00 AM

I am by no means an expert, but probably unless it says "front" on the sticker, its just for the rear axle.

Blazer1970 · 03-13-2003, 09:24 AM

If you are talking about the G80 option in your '86, it is a Gov-lock in the rear only.

CRRoy71 · 03-21-2003, 08:21 AM

Yep, that's the one.
Thanks for the info.

jeffspower · 04-16-2003, 11:21 PM

Gov-lock differentials are lockers- not the limited slip style. They do have clutches but lock solid under torque & wheel spin-out. They work good & hold up ok as long as you don't abuse them too hard or give your truck a change to the "bigs," motor, tires, foot, etc.
-Jeff

CRRoy71 · 04-16-2003, 11:55 PM

Right now with this stock 305, I don't think I have to worry about tearing anything up. Hopefully, in the next year or so I am going with more HP, so that might be something to keep an eye on.

jeffspower · 04-17-2003, 12:00 AM

A friend has one in a early 90's light (semifloat) 14 bolt & abuses it pretty hard at times. He has a mild 350, 5 spd & 3.73's. He got the rear jumping bad enough one time to snap & axle shaft- but the gov-lock survived!!!

-Jeff

TX_Mudder · 04-17-2003, 06:33 AM

Gotta be rear. Other than the military trucks, the general never put a LSD in the front axle AFAIK.
-- Mike

Blazer1970 · 04-17-2003, 07:37 AM

Quote:

Originally posted by TX_Mudder
Gotta be rear. Other than the military trucks, the general never put a LSD in the front axle AFAIK.
-- Mike

Not true. Clutch type posi's were available factory installed in the front axles of '67 - '72 era 4X4s. I have seen glove box stickers posted on this site a few times that prove it.

TX_Mudder · 04-17-2003, 08:32 AM

I learn new things every day

Quote:

Clutch type posi's were available factory installed in the front axles of '67 - '72 era 4X4s

On the down side, those Dana 44s would be of the 260x ujoint variety and would be weaker than the more common later axles.

-- Mike

jeffspower · 04-17-2003, 10:57 PM

some 72's have the larger u-joints, same as the 73-up axles. mine is an early 72 & it does. I am sure the axle is original since my father in law has been around the truck since new (fire dept. truck) & bought it from them in about 1976. I am now the 3rd owner at 85,000 miles.

Just a little info I thought you may like to know!

03-13-2003, 01:18 AM	#1
CRRoy71 Registered User Join Date: Feb 2003 Location: Mont Belvieu, TX Posts: 852	Locking diff??? I was looking at my little sticker in the glove box with all of the options that came with my truck, and noticed that there was an added option Locking differential. Does this mean front only, or front and rear. How can I tell, and how good is the factory locking diff? __________________ Chris '92 ext. cab s/b 4.3L "Sparky" '04 crew cab 2500 4x4 6.0L

03-13-2003, 02:00 AM	#2
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	I am by no means an expert, but probably unless it says "front" on the sticker, its just for the rear axle. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

03-13-2003, 09:24 AM	#3
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	If you are talking about the G80 option in your '86, it is a Gov-lock in the rear only. __________________ Tim

03-21-2003, 08:21 AM	#4
CRRoy71 Registered User Join Date: Feb 2003 Location: Mont Belvieu, TX Posts: 852	Yep, that's the one. Thanks for the info. __________________ Chris '92 ext. cab s/b 4.3L "Sparky" '04 crew cab 2500 4x4 6.0L

04-16-2003, 11:55 PM	#6
CRRoy71 Registered User Join Date: Feb 2003 Location: Mont Belvieu, TX Posts: 852	Right now with this stock 305, I don't think I have to worry about tearing anything up. Hopefully, in the next year or so I am going with more HP, so that might be something to keep an eye on. __________________ Chris '92 ext. cab s/b 4.3L "Sparky" '04 crew cab 2500 4x4 6.0L

04-16-2003, 11:21 PM	#5
jeffspower Well, Whoop-dee-do! Join Date: Mar 2003 Location: Easton, Mo. pop.- me & scarcely a few others Posts: 2,302	Gov-lock differentials are lockers- not the limited slip style. They do have clutches but lock solid under torque & wheel spin-out. They work good & hold up ok as long as you don't abuse them too hard or give your truck a change to the "bigs," motor, tires, foot, etc. -Jeff

04-17-2003, 12:00 AM	#7
jeffspower Well, Whoop-dee-do! Join Date: Mar 2003 Location: Easton, Mo. pop.- me & scarcely a few others Posts: 2,302	A friend has one in a early 90's light (semifloat) 14 bolt & abuses it pretty hard at times. He has a mild 350, 5 spd & 3.73's. He got the rear jumping bad enough one time to snap & axle shaft- but the gov-lock survived!!! -Jeff

04-17-2003, 06:33 AM	#8
TX_Mudder Registered User Join Date: Jun 2001 Location: Houston, TX Posts: 126	Gotta be rear. Other than the military trucks, the general never put a LSD in the front axle AFAIK. -- Mike __________________ http://home.houston.rr.com/chevy73/

04-17-2003, 10:57 PM	#11
jeffspower Well, Whoop-dee-do! Join Date: Mar 2003 Location: Easton, Mo. pop.- me & scarcely a few others Posts: 2,302	some 72's have the larger u-joints, same as the 73-up axles. mine is an early 72 & it does. I am sure the axle is original since my father in law has been around the truck since new (fire dept. truck) & bought it from them in about 1976. I am now the 3rd owner at 85,000 miles. Just a little info I thought you may like to know!



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