FAQ: Locking Rear Diff(Code G80) FAQ

Conman · Post by **Conman** » Wed Oct 16, 2002 5:59 am

Hey,

I was looking in the owner's manual(yeah, I actually read it!) and if you have the "locker" Rear Diff(Code G80 in the glove box), they recommend changing it at first oil change. Figure I'd put this info here since there will be more people(and Dealers) who did not read the manual.

Cheers,

Con

Jim · Post by **Jim** » Wed Oct 16, 2002 11:42 am

I changed mine in the first 500 mi. The parts guy at the dealer said he changed his at 3000 mi. & there was sand from the casting process in his. It sounds like anything with fluid that is not through a filtered media (like engine trans have filters to remove junk) should be inspected.

Post by **HenryJ** » Wed Oct 16, 2002 6:12 pm

Changed mine somewhere around the second oil change, or when I found it in the owners manual, too.

There apeared to be some assembly lube ( white grease?) in the lube. Afterward it seemed to smooth out the lock / unlocking.

Joseph · Post by **Joseph** » Thu Oct 17, 2002 9:42 am

I to read the owners manual. I over look that part,(my bust). I'll get that done at that next oil change along with other recommend stuff by GM. Is this something needs to taken care as soon aspossible or some time soon?

Conman · Post by **Conman** » Thu Oct 17, 2002 8:04 pm

Joseph wrote:I to read the owners manual. I over look that part,(my bust). I'll get that done at that next oil change along with other recommend stuff by GM. Is this something needs to taken care as soon aspossible or some time soon?

I was waiting for my commuter train to come and wanted to take the truck in soon for the 3k service and just saw it. I swear it was not there before!

I don't know why they wanted it changed so soon but I assume it's because of break-in(metal shavings, etc?) for the reason to change it so quickly. Most LSD from the factory only say every 15k(severe duty too) so this is much quicker than expected. Well, this type of traction control is a little different from an LSD unit though. I don't expect this service to cost more than 50 bucks so it's not very expensive to do. If I had more time(and a flat driveway) I would probaby tackle this myself(but I'm too lazy). I still need to change my oil in my Motorcycle still......

Cheers,

Con

marks10cc · Post by **marks10cc** » Wed Aug 13, 2003 7:10 am

I appologize for bringing such an old topic back... but I just saw that the G-80 needs changed early. I was about to just use a vampire pump to extract the oil out of the dif, but does the case need dropped? HenryJ, is that white grease stuff able to be pumped out? I don't think I have the provisions to drop the dif cover and drain it the right way. Got to do this soon though, it feels like my axle is locking up all over town.

It's either that or my tranny is slipping.

Dragonmaster · Post by **Dragonmaster** » Wed Aug 13, 2003 7:17 am

marks10cc wrote:I appologize for bringing such an old topic back... but I just saw that the G-80 needs changed early. I was about to just use a vampire pump to extract the oil out of the dif, but does the case need dropped? HenryJ, is that white grease stuff able to be pumped out? I don't think I have the provisions to drop the dif cover and drain it the right way. Got to do this soon though, it feels like my axle is locking up all over town. It's either that or my tranny is slipping.

All it takes is a new gasket, a wrench and a catch pan or 4l ice cream pale. Take the rear cover off and the fluid will just drain out. If you use the pump you won't get all of the metal shavings or crud in the bottom.

Post by **HenryJ** » Wed Aug 13, 2003 3:12 pm

Dragonmaster wrote:All it takes is a new gasket, a wrench and a catch pan or 4l ice cream pale. Take the rear cover off and the fluid will just drain out. If you use the pump you won't get all of the metal shavings or crud in the bottom.

What He said

It is really easy to do. There is only about 2 quarts of lube to catch.

Wipe everything off with a rag, and put a light coat of silicone on the cover to hold the gasket.

If a gasket is not available, it is acceptable to use RTV in it's place. I prefer the gasket though since the RTV ,if overused can "plug up the works"

There is no way that you could successfully drain all the fluid with a suction pump, IMO.

It's a good excuse to add that flashy diff cover, too. (10 bolt camaro/Astro)

Dragonmaster · Post by **Dragonmaster** » Thu Aug 14, 2003 7:49 am

keep in mind that the synthetic diff lube is known to eat rtv selant so you would need to use dino oil if you plan to not use the gasket.

marks10cc · Post by **marks10cc** » Thu Aug 14, 2003 1:02 pm

*sigh*...

I figured the lazy way wouldn't work. I just need to find a level place to do it. Got a question: Is the gasket for the G80 the 8.5" or the 7.625"? Advanced had both listed for the S10, I'm guessing the LS rear has the bigger gasket? (I've heard about the synth eating the rtv too, but I would prefer the extra protection from the synth, so off I go to find a gasket).

This would be the perfect time to swap out the cover... but the wife factor has my budget limited to just the gasket and oil

Maybe next time. BTW, that cover would look great with metal skid plates.

Thanks for your help guys!

Dragonmaster · Post by **Dragonmaster** » Thu Aug 14, 2003 1:08 pm

marks10cc wrote:*sigh*...

I figured the lazy way wouldn't work. I just need to find a level place to do it. Got a question: Is the gasket for the G80 the 8.5" or the 7.625"? Advanced had both listed for the S10, I'm guessing the LS rear has the bigger gasket? (I've heard about the synth eating the rtv too, but I would prefer the extra protection from the synth, so off I go to find a gasket).

This would be the perfect time to swap out the cover... but the wife factor has my budget limited to just the gasket and oil Maybe next time. BTW, that cover would look great with metal skid plates.

Thanks for your help guys!

If it's a Z then it's the 8.5", if it's a non z then most likely it is the 7.625"

Post by **HenryJ** » Thu Aug 14, 2003 3:13 pm

marks10cc wrote:Is the gasket for the G80 the 8.5" or the 7.625"? Advanced had both listed for the S10, I'm guessing the LS rear has the bigger gasket? (I've heard about the synth eating the rtv too, but I would prefer the extra protection from the synth, so off I go to find a gasket).

BTW, that cover would look great with metal skid plates.

The Crew cabs have the GM 10 bolt w/7.625" ring gear and, if included, the optional RPO code G80- limited slip centrifical locking carrier.

The Z's have the 8.5" ring gear, and also come with RPO G80.

Synth won't eat the RTV. I have multiple trucks in the fleet running synth, no gasket, RTV sealed covers, with no leaks.

I decided to stay with the recommended GL-4 lubricant. I'm a little wary about using the synth personally. I'm just unsure as to how the clutches will react with it. I do like Energy Release also, but won't be adding it to the rear diff. for the same reason.

I may be a little too cautious, but I like to thoroughly understand all the interactions and consequences.

Bluewasp · Post by **Bluewasp** » Mon Aug 25, 2003 3:38 am

Conman wrote:Hey,

I was looking in the owner's manual(yeah, I actually read it!) and if you have the "locker" Rear Diff(Code G80 in the glove box), they recommend changing it at first oil change. Figure I'd put this info here since there will be more people(and Dealers) who did not read the manual.

Cheers,

Con

Question: I have RPO G80 in my new ZR5 and have little over 5k on the clock... I've changed the engine oil at 500miles and again at 3000 with Mobil 1 5w30... I was looking to replace the gear oil with Synthetic since I drive 90mph to 95mph to work ever day. I would like to change everything to Synthetic. What weight should I use in the rear, what type of oil for the trans, and what else should I change? I live in Germany by the way.

adrenalnjunky · Post by **adrenalnjunky** » Mon Aug 25, 2003 5:44 am

One question, (not a flame)

You live int he land of the Uber-Highway and drive at close to triple-digit speeds every day (legally), and you bought a 4wheel drive truck?

Please tell me you have a BMW M5 in the garage to "play" with on the weekends

Bluewasp · Post by **Bluewasp** » Thu Aug 28, 2003 5:42 am

adrenalnjunky wrote:One question, (not a flame)

You live int he land of the Uber-Highway and drive at close to triple-digit speeds every day (legally), and you bought a 4wheel drive truck?

Please tell me you have a BMW M5 in the garage to "play" with on the weekends

I also own a 1996 Grand Sport corvette with a LPE top end. She puts out about 415hp to 420hp at the engine.. Top speed so far on the autobahn has been 180mph... I purchased the truck because I needed something that could carry more then two people and a 4x4 for the harsh winters. My wife has a 2001 Honda Prelude and it has a back seat but no leg room.

download clip:

http://temp.corvetteforum.net/c5/bluewa ... tobahn.avi

quickbiker · Post by **quickbiker** » Thu Aug 28, 2003 9:52 am

Wow, this subject comes up alot. Here's another: http://henryj.lifelesspeople.com/phpBB2 ... light=#790

I know of occurances of people with posi rears that never change oil, then they wonder why the rear bearings go bad. So change that oil now and then

quickbiker · Post by **quickbiker** » Thu Aug 28, 2003 9:54 am

Bluewasp wrote:
adrenalnjunky wrote:One question, (not a flame)

You live int he land of the Uber-Highway and drive at close to triple-digit speeds every day (legally), and you bought a 4wheel drive truck?

Please tell me you have a BMW M5 in the garage to "play" with on the weekends

I also own a 1996 Grand Sport corvette with a LPE top end. She puts out about 415hp to 420hp at the engine.. Top speed so far on the autobahn has been 180mph... I purchased the truck because I needed something that could carry more then two people and a 4x4 for the harsh winters. My wife has a 2001 Honda Prelude and it has a back seat but no leg room.

download clip:

http://temp.corvetteforum.net/c5/bluewa ... tobahn.avi

Hey, when I was in Germany there was a speed limit. But that was back around 89/90. And it sure wasn't 180! Unlike the myth that there is no speed limit, there is.

Bluewasp · Post by **Bluewasp** » Thu Aug 28, 2003 10:25 pm

quickbiker wrote:

Hey, when I was in Germany there was a speed limit. But that was back around 89/90. And it sure wasn't 180! Unlike the myth that there is no speed limit, there is.

Sorry you are mistaken or I don't understand your response. The autobahn has NO speed limit. There wasnít a speed limit in 1989 and 1990Ö Once you enter the autobahn you put your foot down and go! However there are places on the autobahn where speed limits are posted and enforce with cameras. Germans put up speed limits when one autobahn merges with another, construction, or if an on-ramp is on a turn, and damaged roads, etc.Ö.

There has never been a speed limit covering the whole autobahn highway system. The autobahn isn't ONE road itís a system of highways that connect.

If you where here in the summer it is possible the German government imposed a speed limit to reduce pollution. A few years ago pollution levels reach a point that if you had a license plate ending with a even number you could only drive on even days and if you had a odd number then you could only drive on odd days..

quickbiker · Post by **quickbiker** » Fri Aug 29, 2003 1:48 am

I musta been in a different Germany then. I was driving to Belgum from Frankfurt. I think that's the name of the small country on the left. Maybe that isn't the Autobon.

Bluewasp · Post by **Bluewasp** » Sun Aug 31, 2003 12:46 am

I was able to Find 80w-90 GL-5... Can I use that for the locking rear??

S-10CREWCAB.NET

FAQ: Locking Rear Diff(Code G80) FAQ

FAQ: Locking Rear Diff(Code G80) FAQ

Re: FAQ: Locking Rear Diff(Code G80) FAQ