What rear gear oil do you use?
08-27-2004, 09:34 PM
#1
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Join Date: Nov 2002
Location: Michigan
Posts: 1,544
What rear gear oil do you use?
Alright i just had my gears and posi installed. I am in the break in period and have to drive it easy for 500 miles and then change the oil. I plan on doing it in a couple days. I don't know what oil to use? Should I use synthetic or not synthetic? How do you guys change the fluid? pull the cover or get a pump and suck it out of the fill whole? I really don't know if i should use synthetic or not? You just fill full correct? Fill it right to the fill whole? I know what i am doing but just need some encouragement.....lol
08-28-2004, 09:55 AM
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Re: What rear gear oil do you use?
The advice in the post above is good! I do not like synthetic if the posi is a "friction type" as that was not what they were designed for. And yes, if it's a friction type posi you DO need the additive (unless you are using a lubricant that is designed to work without it). I am pretty finicky about my car, but I have to say that I have been using standard gear oil for YEARS without any lubrication related issues. Get a name brand that's on sale at the local auto parts store, that's what I do!
Rich
Rich
08-28-2004, 12:22 PM
#6
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Re: What rear gear oil do you use?
Funny thing is, the manufacturers have changed their opinions over the years. 
You'd have a tough time finding non-synthetic gear lube in anything from the OEM since 2001... limited slip or not.
From Torsen...
Not to mention, the grape smelling gear lube GM recommends and sell$, manufactured by Texaco, is a synthetic.
Seems that just about all the diff makers, Eaton, Torsen, Auburn, etc., will ask you the same thing when you e-mail them about the use of synthetics.... "Follow the manual's viscosity recommendation, otherwise synthetics are fine".
I'd add a friction modifier only as needed. You can buy the FM from Redline and other companies just like anything else. Drive the car in figure 8's, listen for any chatter and add the FM as required. The GM additive seems to breakdown pretty quickly so I wouldn't recommend it.
Good luck.
-Mindgame
You'd have a tough time finding non-synthetic gear lube in anything from the OEM since 2001... limited slip or not.
From Torsen...
Can Torsen recommend an oil for my rear axle?
We suggest that you follow what is listed in your vehicle's owners manual. We do require that a GL4/GL5 class oil be used for the Torsen T-1. The T-1 requires an oil with extreme pressure additives for optimal function. Torsen works well in either synthetic or mineral base oils.
Torsen for GM vehicles:
Is it true that the Torsen unit in the production Camaro needs the GM modifier added?
GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.
We suggest that you follow what is listed in your vehicle's owners manual. We do require that a GL4/GL5 class oil be used for the Torsen T-1. The T-1 requires an oil with extreme pressure additives for optimal function. Torsen works well in either synthetic or mineral base oils.
Torsen for GM vehicles:
Is it true that the Torsen unit in the production Camaro needs the GM modifier added?
GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.
Seems that just about all the diff makers, Eaton, Torsen, Auburn, etc., will ask you the same thing when you e-mail them about the use of synthetics.... "Follow the manual's viscosity recommendation, otherwise synthetics are fine".
I'd add a friction modifier only as needed. You can buy the FM from Redline and other companies just like anything else. Drive the car in figure 8's, listen for any chatter and add the FM as required. The GM additive seems to breakdown pretty quickly so I wouldn't recommend it.
Good luck.
-Mindgame
08-28-2004, 04:37 PM
#7
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Re: What rear gear oil do you use?
Thanks guys. Great post mindgame 
I guess it really doesn't matter as long as you change it and get the right viscosity. I think i'll try just a mineral based oil without the FM from GM and change it more frequently.
I guess it really doesn't matter as long as you change it and get the right viscosity. I think i'll try just a mineral based oil without the FM from GM and change it more frequently.
08-28-2004, 04:42 PM
#8
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Re: What rear gear oil do you use?
I'm really not sure what type this Zexel diff is? Anyobdy know? I think i remember reading it but can't remember which type it was.
http://www.slponline.com/view_produc...RTNUMBER=65002
http://www.slponline.com/view_produc...RTNUMBER=65002
08-28-2004, 07:19 PM
#9
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Posts: 305
Re: What rear gear oil do you use?
When I had the Zexel I had good luck with Redline shock proof oils. The Moser/Eaton didnt like it so much, the clutches would screem and howl on turns. Needless to say I switched back to regular 80w90 with 2 bottles of GMLS additive and it slowly became quite.
Personaly I liked the idea of an anti-shock oil in an all gear diff like the Torsen/Zexel. I know the GL-5 oil has a shock suppressant adequate for the ring and pinion but the worm gears have looser clearences and really get slammed when dumping the clutch. The redline shock proof oils have a...well I'll let them say it.......A unique lubricant containing a suspension of solid microscopic particles as an extreme pressure agent--unique solid dispersion which cushions gear teeth to help prevent tooth breakage and allows the use of lower viscosities. The viscosity characteristics allow the lubricant to resist throwoff and provide a film thickness greater than an SAE 250 grade, with the same low fluid friction as with our 80W140. Recommended for heavily-loaded racing differentials and transmissions, Off Road racing and problem gearboxes. Offers a "best of both worlds" balance of relatively low drag and the utmost in protection.RL.
Personaly I liked the idea of an anti-shock oil in an all gear diff like the Torsen/Zexel. I know the GL-5 oil has a shock suppressant adequate for the ring and pinion but the worm gears have looser clearences and really get slammed when dumping the clutch. The redline shock proof oils have a...well I'll let them say it.......A unique lubricant containing a suspension of solid microscopic particles as an extreme pressure agent--unique solid dispersion which cushions gear teeth to help prevent tooth breakage and allows the use of lower viscosities. The viscosity characteristics allow the lubricant to resist throwoff and provide a film thickness greater than an SAE 250 grade, with the same low fluid friction as with our 80W140. Recommended for heavily-loaded racing differentials and transmissions, Off Road racing and problem gearboxes. Offers a "best of both worlds" balance of relatively low drag and the utmost in protection.RL.
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