G87 Powerloc diff - The 1947 - Present Chevrolet & GMC Truck Message Board Network

boot85 · 12-06-2006, 07:27 PM

This is the rear end code for the truck I bought last week. Are they any good? I saw a post today and somebody said that the G80 diffs were basically garbage, is this one in the same family? Also it does not have a ratio listed does any one have a quess as to what it may be? I have not driven it yet so I am clueless as to what RPM's it turns. It is on a 3/4 ton so my guess would be 4:10 or 4:56.

skchevota · 12-06-2006, 11:14 PM

G87 is a dana 60 with a powerlock... Very nice.
It should be either 3.54 or 4.10 gears

72dually · 12-06-2006, 11:29 PM

Quote:

Originally Posted by boot85

This is the rear end code for the truck I bought last week. Are they any good? I saw a post today and somebody said that the G80 diffs were basically garbage, is this one in the same family? Also it does not have a ratio listed does any one have a quess as to what it may be? I have not driven it yet so I am clueless as to what RPM's it turns. It is on a 3/4 ton so my guess would be 4:10 or 4:56.

Just to clarify...........G80 is a code for posi, and aren't all necessarly junk. Lets just say the gov locks aren't the preffered unit. G80 code has been used for years, some units are very strong, some are indeed garbage

ks147j111928 · 12-07-2006, 01:12 AM

well, crap. I have a G80 positrac in a parts truck, is there a definite way to tell if it's junk or not? It's a 4.11 ratio BTW...

Blazer1970 · 12-07-2006, 08:08 AM

Quote:

Originally Posted by ks147j111928

well, crap. I have a G80 positrac in a parts truck, is there a definite way to tell if it's junk or not? It's a 4.11 ratio BTW...

If it is from the '67 - '72 era, a G80 is a normal Eaton limited slip (posi). Sometime in the mid '70s GM switched to the Eaton automatic locker ("gov-lock") while still using the G80 RPO code. The gov-lock is the one that people don't like.

boot85 · 12-07-2006, 08:19 AM

The one on the truck is original so it must be the '67 - '72 era normal Eaton limited slip (posi). I am assuming that it must be a Dana since it is not an HO52.

Blazer1970 · 12-07-2006, 04:53 PM

Quote:

Originally Posted by boot85

The one on the truck is original so it must be the '67 - '72 era normal Eaton limited slip (posi). I am assuming that it must be a Dana since it is not an HO52.

Yours, with a Dana 60 and the G87 option is a Dana Powerlock which is also a limited slip. The Eaton limited slip was used in the corporate axles (12 bolt and in later years the 10 bolt).

72dually · 12-07-2006, 05:20 PM

Quote:

Originally Posted by Blazer1970

Yours, with a Dana 60 and the G87 option is a Dana Powerlock which is also a limited slip. The Eaton limited slip was used in the corporate axles (12 bolt and in later years the 10 bolt).

Yeppers, and both units are very reliable

12-06-2006, 07:27 PM	#1
boot85 71 Chevy Join Date: May 2006 Location: Madison, Wisconsin Posts: 83	G87 Powerloc diff This is the rear end code for the truck I bought last week. Are they any good? I saw a post today and somebody said that the G80 diffs were basically garbage, is this one in the same family? Also it does not have a ratio listed does any one have a quess as to what it may be? I have not driven it yet so I am clueless as to what RPM's it turns. It is on a 3/4 ton so my guess would be 4:10 or 4:56. __________________ 71 C10 72 C20 62 Chevy II 2DR HT

12-06-2006, 11:14 PM	#2
skchevota Registered User Join Date: Oct 2006 Location: Evans, Colorado Posts: 530	Re: G87 Powerloc diff G87 is a dana 60 with a powerlock... Very nice. It should be either 3.54 or 4.10 gears

12-07-2006, 01:12 AM	#4
ks147j111928 ASE Certified Spoon Operator Join Date: Oct 2006 Location: Colorado Springs, CO Posts: 157	Re: G87 Powerloc diff well, crap. I have a G80 positrac in a parts truck, is there a definite way to tell if it's junk or not? It's a 4.11 ratio BTW... __________________ My six is bigger than your eight 67 K20 292 +.060" SM465 NP203 3.73s 86 4Runner, the daily on 31s 85 4Runner, the wheeler on 38s 92 x-cab truggy project for 2017... tons and 42s and V8 power

12-07-2006, 08:19 AM	#6
boot85 71 Chevy Join Date: May 2006 Location: Madison, Wisconsin Posts: 83	Re: G87 Powerloc diff The one on the truck is original so it must be the '67 - '72 era normal Eaton limited slip (posi). I am assuming that it must be a Dana since it is not an HO52. __________________ 71 C10 72 C20 62 Chevy II 2DR HT



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