GM Drivetrain & Suspension Chassis | Transmission| Driveshaft | Gears/Rear End/Differential | Traction Aids

Changing Diff Fluid...question...

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Old Mar 15, 2007 | 11:15 PM
  #11  
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You don't need the additive - just put in the synthetic 75W and be done.
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Old Mar 16, 2007 | 09:59 AM
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Originally Posted by agreif
I thought the additive was only for the clutches? I believe the G80 does not have any clutches in, hence no additive. Someone correct me if I'm wrong.
The G80 is only the RPO Code for "Limited Slip Diffrential" wiht GM. GM OEM G80 Diff's are equiped with the clutch packs. You can put an Eaton LSD in and some don't have the clutch packs, gears instead...but it'll still be a G80 RPO Code.

If your diff has clutches, then you DO have to use the Additive. If you have a gear driven LSD.....GM and I still reccomend that you use the additive, although you don't HAVE to.

What's wrong with a little extra protection anyway? I know there's times where I wished I could have use 2 condoms instead of one ya know?
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Old Mar 16, 2007 | 08:59 PM
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OK, I don't mean to come off like an *** here, but I think you may be mistaken. If you have opened up a factory diff and seen a clutch pack then I stand corrected, but based on what I've read on eaton's site, teh G80 is a mechanical only unit while a true LSD has teh clutch pack, I always though the name of the G80 was a little misleading by GM. http://www.eaton.com/EatonCom/Market...rols/index.htm
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Old Mar 17, 2007 | 08:06 AM
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POS email notification!!! Here I was thinking nobody responded to my post cause i didn't get notified and all along yall were replying...DUMB! I have a 1500 with a 10-bolt rear...not sure about the code, would have to go out and check, would I be able to just look at the G80 in the VIN and tell?
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Old Mar 17, 2007 | 08:23 AM
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Originally Posted by TarheelZ
Not trying to be a dick, but I've heard that before from dealership employees, BUT the shop manager assured me that the G80 in my ZR2 did NOT use the additive. It was the same 8.5" 10 bolt that's in the full-size trucks. This debate's been going on for years over on ZR2.com.
Brother I guess you'll just have to take the Carrier out of the rear diff. and open it up and see if you got clutch packs instead of spider gears.
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Old Mar 17, 2007 | 08:24 AM
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Originally Posted by Carlos
POS email notification!!! Here I was thinking nobody responded to my post cause i didn't get notified and all along yall were replying...DUMB! I have a 1500 with a 10-bolt rear...not sure about the code, would have to go out and check, would I be able to just look at the G80 in the VIN and tell?
Shoot me your last 8 digits of your vin and I can tell you what your truck has in it if it hasn't been changed.
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Old Mar 17, 2007 | 08:28 AM
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Originally Posted by agreif
OK, I don't mean to come off like an *** here, but I think you may be mistaken. If you have opened up a factory diff and seen a clutch pack then I stand corrected, but based on what I've read on eaton's site, teh G80 is a mechanical only unit while a true LSD has teh clutch pack, I always though the name of the G80 was a little misleading by GM. http://www.eaton.com/EatonCom/Market...rols/index.htm

No harm no faoul friend. In fact you are correct! G80 is an RPO accronym that GM adopted to signify that you have a Limited Slip Diff.

Eaton has a G80 Locker Diff. As a matter of fact I have one in my truck and it is gear driven. But I still use the Friction Modifier.

The OEM diff. that I broke into 100 pieces was a GM OEM G80 Limited Slip Diff. and it had clutches in it.

GM also has diffrent carriers with diffrent internals. Some with clutch packs and some with gears.

I could fax you some GM CAD Illustrations if it would help.
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Old Mar 17, 2007 | 08:52 AM
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Ok i didn't see G80 in the glove box, the only G's i saw in there were GT4 and G65...
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Old Mar 17, 2007 | 10:21 AM
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GT4 is 3.73 gears
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Old Mar 17, 2007 | 12:54 PM
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G80 here, and no whale sperm used. Mobil 1 75-90 synthetic. Haven't had any issues
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