Gear Oil Additive - 2oz or 4oz? - Drivetrain - Firebird Nation

Jump to content


FirebirdNation.com is the premier Pontiac Firebird forum on the internet. Supporting Members do not see the above ads.
Photo
- - - - -

Gear Oil Additive - 2oz or 4oz?


  • Please log in to reply
3 replies to this topic

#1 Kam1685

Kam1685

    Firebird Newbie

  • New Member
  • Pip
  • 8 posts
  • Gender:Male
  • First Name:W
  • City:Town
  • State or Province:TN
  • Country:USA
  • Year: 1996
  • Make: Pontiac
  • Model: Firebird Formula
  • Engine: 5.7
  • Transmission: Manual

Posted A week ago

I keep seeing posts stating that the limited slip rear end takes 4 ounces of rear differential additive.  But, my 1996 manual states it requires 2 ounces (59ml) of additive.  Is there a reason for the conflicting info?  Thanks. 


Edited by Kam1685, A week ago.


#2 ZumpTA

ZumpTA

    Firebird Master Tech.

  • Administrator
  • 2270 posts
  • Gender:Male
  • First Name:Tony
  • City:Holiday
  • State or Province:FL
  • Country:USA
  • Year: 1993
  • Make: Pontiac
  • Model: Trans Am
  • Engine: LT1
  • Transmission: 6-Spd

Posted A week ago

I am seeing the same thing.  To be honest, I used a whole tube of Trans-X (7oz) in 2003 when I got my T/A because the rear chattered and shuddered around corners.  Had no issues whatsoever with that quantity. Many claim "too much" causes slipping, and maybe that's true, but I guess it wasn't for me, or maybe 7oz isn't "too much". 

 

My diff cover began leaking about 2 years ago, removed cover, drained, cleaned out remaining oil, cleaned magnet, flattened holes on diff cover, installed new gasket, bolted up, filled, added 7oz of Trans-X, and all is good.  I can break both wheels loose at 45MPH, if there was going to be any slipping in any component of my drive-train, it would manifest under that load.   ...but I go sideways with two smoking tires, not straight with only one.  My opinion is 7oz of Trans-X is fine. Nearly twenty years on and I have no issues with my rear end.  Now, that is not to say that Trans-X is "just as potent" as all other brands.  Maybe it's the weakest and 7oz of GM's brand or someone else's *is* way too much.

 

 

Go to the dealer and buy their "bottle".  If your car is 2oz, that's what they will sell you.  If it needs 4oz, that's what you will get.  Should be around $10.

 

Also read that some synthetic oils like Amsoil have the additive in them already.  If you chose to go that route, verify that whatever product you buy does indeed have those additives.

 

EDIT:  Looked over at shbox.com   He has a GM 4oz bottle pictured sitting on (of all things) a 1996 service manual.  I'd say 4oz is the answer.  http://shbox.com/1/lsa.jpg

 

 

Conflicting info is hard to get through.  Maybe they initially used 2oz but later found 4oz was required and released a service bulletin.  Pretty sure our manuals advise against synthetic oil in the rear end, but if you go to Chevy now, they recommend (and sell) synthetic for back there.  Times, technology, and formulations change, as such, so do the recommendations.  Looking at "general recommendations" from LSD manufactures such as Yukon, they call for 4oz to be used with 3-4 quarts.  I think our diff is 1.5-2 quarts, so 2oz sounds about right by "general standards".  However, GM's bottle is 4oz and is not marked in such a way as to gauge what half a bottle is, so I assume GM expects us to use the entire 4oz.   Since this is so confusing, my advice would be to drive to (or call) Chevy and ask a Service Tech how much they use in a '96 Z28 because there is no straight answer to be found...


"There are two major products that come out of Berkeley: LSD and UNIX.
We don't believe this to be a coincidence."
-- Jeremy S. Anderson

"Man is the best computer we can put aboard a spacecraft...
and the only one that can be mass produced with unskilled labor."
-- Wernher von Braun


#3 Injuneer

Injuneer

    Just Trying to Help

  • Administrator
  • 14020 posts
  • Gender:Male
  • First Name:Fred
  • City:Central NJ
  • State or Province:NJ
  • Country:USA
  • Interests:Licensed Professional Engineer (Mechanical)
  • Year: 1994
  • Make: Pontiac
  • Model: Firebird Formula
  • Engine: 381ci LT1 stroker
  • Transmission: TH400 + GV O/D

Posted A week ago

Apparently is depends on the year of the car.  My 1994 Owner's Manual and Factory Service Manual both indicate 4 OZ.  The 1996 FSM indicates 2 OZ.  Never noticed that difference before.  Not aware of any significant change in sourcing of the differentials, both should be Auburn cone type units, and both the 1994 and 1996 FSM's confirm this.


1994 FIREBIRD FORMULA
FRED

 
381ci all-forged stroker (Callies Stealth, Oliver billet rods, BME 2618-T61 nitrous pistons) - 10.8:1 - CNC LT4 heads/intake - Comp Cams solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74#/HR injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11 Pro-Street gears - AS&M headers - true duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP / 800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117 MPH straight motor
 
https://www.firebird...9_698_32777.jpg

 


#4 Kam1685

Kam1685

    Firebird Newbie

  • New Member
  • Pip
  • 8 posts
  • Gender:Male
  • First Name:W
  • City:Town
  • State or Province:TN
  • Country:USA
  • Year: 1996
  • Make: Pontiac
  • Model: Firebird Formula
  • Engine: 5.7
  • Transmission: Manual

Posted A week ago

Thanks.  I’m going to use the standard gear oil with the GM additive. There’s also conflicting info about using synthetics that already have the additive included.  

 

So the 95 and 97 manuals both state 4oz as well. The 96 manual states 2oz. That’s very weird.  I’ll just use the full 4oz bottle and see how it goes.  






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users