changing diff fluid,how much additive to use
Thread Starter
Burning Brakes
Joined: Mar 2005
Posts: 1,042
Likes: 0
changing diff fluid,how much additive to use
I'm hoping to quiet down a slight "whine"I think is coming from the diff,plus its never been changed in its 112k life.I'm using 2 quarts of mobil 1 75w90 gear oil,as far as the additive,I've heard add 4 ounces,but I've also heard 8 ounces.well,I got the additive at the autoparts store,it says "trans X posi trac Lim.slip gear oil additive meets GM part #1052358"its a 7 OUNCE tube.should I A.use all 7 ounces B.only 4 ouncesC.dont even use it,and go to dealer and get the GM stuff,leaning toward A,but a little 
and just want to make sure
and just want to make sure
Race Director
Joined: Jun 2004
Posts: 13,969
Likes: 710
From: WI
I got a bottle of penzoil for mine, it said on the label to NOT add additive. I intend to replaced the penz with schaeffers after reading this test... also it shows Lukus additive to be bad, adding to much air to the oil.
http://www.bobistheoilguy.com/gearoiltest.htm
D'oh the site is being updated. There was a nice gear lube test with pictures there!
http://www.bobistheoilguy.com/gearoiltest.htm
D'oh the site is being updated. There was a nice gear lube test with pictures there!
Thread Starter
Burning Brakes
Joined: Mar 2005
Posts: 1,042
Likes: 0
Originally Posted by steve9899
C. Go to the dealer and get the GM stuff.
The manual says to use one bottle (4 oz)
Killebrew says to use two.
Most follow Killebrew over the manual.
Also the manual specifies 80w90.
The manual says to use one bottle (4 oz)
Killebrew says to use two.
Most follow Killebrew over the manual.
Also the manual specifies 80w90.
I think each bottle is over $10(not sure though)compared to the Trans x stuff($4)I guess I'd rather have a thinner wallet,but safer in stead of sorry,but if they came with 4 ounces from the factory,why does Gordon say use 2?wil it quiet it down more,produce less wear?anyone?
Safety Car
Joined: Apr 2003
Posts: 3,793
Likes: 9
From: VA
Originally Posted by vette&f-bod lover
I think each bottle is over $10(not sure though)compared to the Trans x stuff($4)
Le Mans Master
Joined: Oct 2004
Posts: 7,706
Likes: 485
From: Everett WA
C4 of Year Finalist (appearance mods) 2019
Originally Posted by vette&f-bod lover
actually that should have been D.go to the dealer and get 2 bottles of the GM stuff I think each bottle is over $10(not sure though)compared to the Trans x stuff($4)I guess I'd rather have a thinner wallet,but safer in stead of sorry,but if they came with 4 ounces from the factory,why does Gordon say use 2?wil it quiet it down more,produce less wear?anyone?
I think each bottle is over $10(not sure though)compared to the Trans x stuff($4)I guess I'd rather have a thinner wallet,but safer in stead of sorry,but if they came with 4 ounces from the factory,why does Gordon say use 2?wil it quiet it down more,produce less wear?anyone?
so 2 is better than one. The additive is what keeps the clutch packs in the diff from binding when going around turns.
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Race Director
Joined: Feb 2003
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From: Kingman AZ
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My notes from Gordon's 2003 class says add 2 botles of GM's posi fluid first then top off with Mobil 1 synthetic gear oil.
Chris Petris sells a kit so you can drill and tap a hole in the diff. He says draining from the bottom is better than the suction gun method as any foriegn particles will be laying at the very bottom of the diff.
Chris Petris sells a kit so you can drill and tap a hole in the diff. He says draining from the bottom is better than the suction gun method as any foriegn particles will be laying at the very bottom of the diff.
