Is limited slip additive necessary?
#1
Member
Thread Starter
Is limited slip additive necessary?
I purchased a 10 bolt 3.42 limited slip rear end to put in my Trans am and need to change the fluid in it. I didn't see limited slip additive at O'Rileys so I bought 3 quarts of Castrol 80w-90 'limited slip' Which I assume has the additive already in it. A friend at work is now telling me that I really need the special GM additive. Do I?
#2
Supreme Member
iTrader: (1)
Join Date: Aug 2007
Location: Bright, IN
Posts: 1,390
Likes: 0
Received 0 Likes
on
0 Posts
Car: '86 Bird, 96 ImpalaSS, 98 C1500XCab
Engine: LG4, LT1, L31
Transmission: 700R4, 4L60E, 4L60E
Axle/Gears: 3.73 Tors, 4.88 spool, 3.73 Eaton
Re: Is limited slip additive necessary?
Yes, you need the additive.
I'm pretty sure "limited slip" on the Castrol bottle legally means it's compatible with limited sip differentials, and doesn't contain the additives or properties that will prevent your clutches from chattering.
It's deceptive advertising to entice more people to buy their product that otherwise may choose a different brand.
I'm pretty sure "limited slip" on the Castrol bottle legally means it's compatible with limited sip differentials, and doesn't contain the additives or properties that will prevent your clutches from chattering.
It's deceptive advertising to entice more people to buy their product that otherwise may choose a different brand.
#3
Supreme Member
Re: Is limited slip additive necessary?
Lucas claims with their stuff you don't but not sure about castrol. I always use the additive no matter what usually the yukon stuff. I am going to try the GM stuff the next time around about $14 at the dealer.
Oriley's usually has this stuff in stock but I have heard mixed things.
http://www.oreillyauto.com/site/c/de...=limited+slip+
Oriley's usually has this stuff in stock but I have heard mixed things.
http://www.oreillyauto.com/site/c/de...=limited+slip+
#4
Supreme Member
iTrader: (1)
Join Date: Aug 2007
Location: Bright, IN
Posts: 1,390
Likes: 0
Received 0 Likes
on
0 Posts
Car: '86 Bird, 96 ImpalaSS, 98 C1500XCab
Engine: LG4, LT1, L31
Transmission: 700R4, 4L60E, 4L60E
Axle/Gears: 3.73 Tors, 4.88 spool, 3.73 Eaton
Re: Is limited slip additive necessary?
I've used the generic parts-store additives from AutoZone and AdvanceAuto with regular Valvoline 80w90, and they work just as well as the GM stuff.
#5
Senior Member
iTrader: (2)
Join Date: May 2003
Location: Huntsville, AL
Posts: 539
Likes: 0
Received 2 Likes
on
2 Posts
Car: 87 GTA, 88 GTA, 92 TA, 72 RS SS
Engine: 350, 350, 305, 396
Transmission: T56, 700r4, 700r4, T56
Axle/Gears: 3.42, 3.23, 3.23, 3.73
Re: Is limited slip additive necessary?
Just read the label on the gear oil you bought, if it says for limited slip top off only you need the LSD additive. if it says for limited slip differentials it already has the friction modifiers added so you do not need any more additive.
#6
Member
Join Date: Jan 2011
Location: Saratoga Area, New York
Posts: 446
Likes: 0
Received 1 Like
on
1 Post
Car: 1990 Formula Firebird
Engine: 305 TBI (LO3)
Transmission: WC T-5 out of an 88 T/A
Axle/Gears: 10 bolt, 3.42 & Torsen Posi
Re: Is limited slip additive necessary?
I purchased a 10 bolt 3.42 limited slip rear end to put in my Trans am and need to change the fluid in it. I didn't see limited slip additive at O'Rileys so I bought 3 quarts of Castrol 80w-90 'limited slip' Which I assume has the additive already in it. A friend at work is now telling me that I really need the special GM additive. Do I?
#7
Re: Is limited slip additive necessary?
If you bought a rear end with the Auburn differential then you may need to use 2 bottles of the GM LSD oil additive. I haven't seen a Auburn that worked smoothly with only one bottle of the additive. You really need to know what differential you have before putting oil in it.
Trending Topics
#8
Supreme Member
Join Date: Jul 1999
Location: Calimesa, California, U.S.
Posts: 3,458
Likes: 0
Received 39 Likes
on
27 Posts
Re: Is limited slip additive necessary?
Always add the GM Limited Slip (Posi) additive to the differential. Yes, it sometimes takes a couple of bottles to get it right. You cannot skip out on this.
Last edited by Pro Built Automatics; 08-26-2016 at 10:23 AM.
#9
Supreme Member
iTrader: (8)
Join Date: Oct 2001
Location: Il
Posts: 11,723
Received 773 Likes
on
520 Posts
Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: Is limited slip additive necessary?
GM and ford have the best additive, I haven't had any of the parts store stuff work without a serious over dose of it and then it doesn't last near as long as the GM or Ford stuff.
#11
Supreme Member
iTrader: (1)
Join Date: Aug 2007
Location: Bright, IN
Posts: 1,390
Likes: 0
Received 0 Likes
on
0 Posts
Car: '86 Bird, 96 ImpalaSS, 98 C1500XCab
Engine: LG4, LT1, L31
Transmission: 700R4, 4L60E, 4L60E
Axle/Gears: 3.73 Tors, 4.88 spool, 3.73 Eaton
Re: Is limited slip additive necessary?
Honestly, one bottle alone has always done it for me, whether GM or generic parts-store stuff.
The only exception was a long time ago when I naively refilled a new vehicle (Auburn posi) with Amsoil synthetic. It took 2 bottles of the GM additive to restore acceptable performance to that one.
Thread
Thread Starter
Forum
Replies
Last Post
lonestar7
Engine/Drivetrain/Suspension Wanted
9
11-05-2012 05:30 PM
Kyle92GT
Transmissions and Drivetrain
8
03-26-2001 09:51 AM
Kyle92GT
Tech / General Engine
4
03-25-2001 09:36 PM