posi lube
Thread Starter
Pro
Joined: May 2001
Posts: 571
Likes: 5
From: usa
posi lube
does it have to be GM posi lube, or will any posi lube work like CRC TRANS X posi trac lube
http://www.napaonline.com/Catalog/Ca...508_0006475893
http://www.napaonline.com/Catalog/Ca...508_0006475893
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
USE the GM stuff. You are splitting hairs. I will not, use, try, invent, conger-up any other product for the rear diff. I do not care what they say...because the ill-effects will be much greater that the few bucks difference.
Once again...the choice is yours.
DUB
Once again...the choice is yours.
DUB
Burning Brakes
Joined: Feb 2012
Posts: 925
Likes: 7
I agree. There are a lot of different brands and types of gear oil and additives (synthetics, etc.). Gary Ramadei, one of the few experts on Corvette rears, recommends the original GM positraction additive. And that's what I put in the 3.73 that Gary did for me, even though I already bought the synthetic stuff that the clown at the Texas Differential Rebuilders Training and Screen-door Company recommended.
Racer
Joined: Dec 2006
Posts: 416
Likes: 40
From: Swansea IL
There were a bunch of opinions that the new GM posi lube was all you needed for the rear.
I installed a new posi diff in my 1970 BB Car and put the new GM lube in. After driving on the highway for a couple of hours and getting on the exit ramp, hard popping as I made the left turn off the ramp.
You NEED the friction modifier in the diff. The new lube is no better than the old stuff. IN fact, the old stuff may have been better for the old posi friction plates.
Bob
I installed a new posi diff in my 1970 BB Car and put the new GM lube in. After driving on the highway for a couple of hours and getting on the exit ramp, hard popping as I made the left turn off the ramp.
You NEED the friction modifier in the diff. The new lube is no better than the old stuff. IN fact, the old stuff may have been better for the old posi friction plates.
Bob
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Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
My take is if its an older or original rear, stay with Dino juice! A fresh rebuild or new, use synthetic.
Burning Brakes
Joined: Oct 2001
Posts: 1,241
Likes: 4
From: Okinawa Okinawa
Open up the plug where you put the gear oil in.
Use a pump to siphon the old gear oil out. You will need a hose that can go all the way to the bottom of the diff. Pretty easy and doesn’t take any time at all.
Use a pump to siphon the old gear oil out. You will need a hose that can go all the way to the bottom of the diff. Pretty easy and doesn’t take any time at all.
Melting Slicks
Joined: Jan 2000
Posts: 3,321
Likes: 523
From: home
Here's my take on the diff additive. Fine for a normal street car but I would not use it in any performance application. Here's why. The friction modifier makes the posi plates slip easier. Slippage = heat. Not good. We have 1000's of race miles in Corvettes, Camaros, Firebirds, Solstices, Mustangs, etc and none of them have ever had a friction modifier. As far as gear oil, each rear gets Mobil 1 synthetic 75-90 Delvac gear oil- unless the customer has a gear oil of his choice, but it is always a synthetic. I've used Red Line and Royal Purple with the same results as Mobil 1. Doesn't matter is it is a brand new rear, a rebuilt rear, or one that has miles on it. This same gear oil goes in all the rears we service. We have not experienced a gear oil related failure at all.
Thread Starter
Pro
Joined: May 2001
Posts: 571
Likes: 5
From: usa
Here's my take on the diff additive. Fine for a normal street car but I would not use it in any performance application. Here's why. The friction modifier makes the posi plates slip easier. Slippage = heat. Not good. We have 1000's of race miles in Corvettes, Camaros, Firebirds, Solstices, Mustangs, etc and none of them have ever had a friction modifier. As far as gear oil, each rear gets Mobil 1 synthetic 75-90 Delvac gear oil- unless the customer has a gear oil of his choice, but it is always a synthetic. I've used Red Line and Royal Purple with the same results as Mobil 1. Doesn't matter is it is a brand new rear, a rebuilt rear, or one that has miles on it. This same gear oil goes in all the rears we service. We have not experienced a gear oil related failure at all.
mine seems to have stopped now
Melting Slicks
Joined: Jan 2000
Posts: 3,321
Likes: 523
From: home
Most do not make any noises. The ones that do, well...........that's the price we pay for performance, It is not that bad. I hear more noises from the front tires when turning in the parking lot in Grand Sports and Zo6's. You should have heard the rears in the 80's F car rears I built. You'd think the thing was self destructing, but is was normal when they got hot.
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
I know both Tom (Tom's Differentials) and Gary recommend Dino lube and say not to run synthetic. Both of these guys are very smart and know what they are doing. That being said I have run Mobile 1 synthetic for years with no adverse affects. A close friend of mine owns and drives a semi truck hauling gravel, dirt, etc... He has one million miles on this truck. A couple of years ago he broke the power divider in the front differential. When he pulled it apart the gears in the diff looked like new and turned smooth as silk with very little effort. It has always had Mobile 1 in it. He said when he started running Mobile 1 synthetic in his trucks years ago the differential temps went down. Hard to argue against that kind of success!
As far as posi fluid, over the years I've run different brands (whatever was on the shelf) in posi units that were popping. Pour it in, made figure 8's in a parking lot until they got smooth. No matter the brand, it always worked. Also worked in old Jeep Quadratrac transfer cases.
As far as posi fluid, over the years I've run different brands (whatever was on the shelf) in posi units that were popping. Pour it in, made figure 8's in a parking lot until they got smooth. No matter the brand, it always worked. Also worked in old Jeep Quadratrac transfer cases.
Instructor
Joined: Apr 2013
Posts: 116
Likes: 0
From: Liverpool New York
Can you explain the figure eights? I have a new 3.54 with a vibration (maybe 6 miles on it) and I'm thinking maybe I should do some figure eights and this might clean it up a little (?). I have the Royal Purple in it right now.
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
You do figure 8's to work the fluid into the posi clutches. The inside tire on a turn rotates slower than the outside tire so it makes the clutch plates also rotate at different speeds and slide against each other. Turn the other way and the clutch pates are reversed in which set turns faster. It's like grabbing the stub axles and turning them back and forth, kinda.