Redline Differential fluid....Question
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,889
Likes: 21
From: Olathe, Kansas
Redline Differential fluid....Question
I know this has been discussed many times over, but I cannot seem to find a definitive answer on this. I'm about to change my Differential fluid and use the Redline SAE75W90 API GL-5+ Hypoid gear oil. The bottle states "Contains additive for limited-slip diferentials". Does this mean I do not have to add the GM Additive (#1052358)? Or the Redline brand of additive? For those of you actually running this Redline product, what did you do, and what have the results been? Thanks in advance for all your help!
Melting Slicks
Joined: Mar 2005
Posts: 2,364
Likes: 1
From: Rugby North Dakota
I had this same question about a year ago - I think you are using a Redline SYNTHETIC gear lube which HAS limited slip addative already in it - I thhk I put a LITTLE bit of GM addative in, but not more than couple spoonfuls, so to speak
Advice I was given was do as described above - then drive and listen for clutch "chatter" coming from rear end - if you hear "chatter," then add more addative - if no chatter, then good to go
Advice I was given was do as described above - then drive and listen for clutch "chatter" coming from rear end - if you hear "chatter," then add more addative - if no chatter, then good to go
Racer
Joined: Mar 2004
Posts: 382
Likes: 0
From: Arlington VA
I am running the exact same fluid (Redline 75W90) in the rear of my stock '03 Z06. I am extremely confident that NO additional fiction modifier is necessary based on two things:
1. I read either in my owners manual or in my GM 2003 service manual (I can't remember which but it was definately OFFICIAL documentation) that GM wants you to add I believe 5oz (I appologize for not being able to state it exactly but I'm going off of memory) to the total amount of gear oil your rear differential will hold. At any rate, I do distinctly remember calculating this ratio out as a percentage because that is how Redline expresses the amount of friction modifier contained in the 75W90. To make a long story short, the percentages matched-up almost exactly. Truly, the numbers were almost an exact match!
2. I have driven my vette for over 10,000 miles with ZERO problems. No noise, no slip, no anything it's not supposed to do.
HTH,
- Max
1. I read either in my owners manual or in my GM 2003 service manual (I can't remember which but it was definately OFFICIAL documentation) that GM wants you to add I believe 5oz (I appologize for not being able to state it exactly but I'm going off of memory) to the total amount of gear oil your rear differential will hold. At any rate, I do distinctly remember calculating this ratio out as a percentage because that is how Redline expresses the amount of friction modifier contained in the 75W90. To make a long story short, the percentages matched-up almost exactly. Truly, the numbers were almost an exact match!
2. I have driven my vette for over 10,000 miles with ZERO problems. No noise, no slip, no anything it's not supposed to do.
HTH,
- Max
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Redline has several products. The 75W-90 has the limited slip additive in it already. The 75W-90NL does not have the limited slip additive in it at all. Redline also makes their own limited slip additive. You can mix and match any of these to get the ratio you want. I think you will find that the 75W-90 out of the bottle with work fine without any more additive. Too much additive and you lose limited slip capability, too little and it will chatter. After you install it, take the car to a parking lot and do some figure 8's and check for chatter. This will also work the fluid into the clutch packs. If it chatters, then a little more additive may be necessary. If you find that only one tire spins, then you can back off on the additive by replacing some fluid with the "NL" type.
This is all based on a stock rear end, if you have a DTE clutch pack then a different recipe is required.
This is all based on a stock rear end, if you have a DTE clutch pack then a different recipe is required.
Drifting
Joined: Feb 2007
Posts: 1,993
Likes: 7
From: LaPine Oregon
Call Redline
Just call Redline Oil main office in Benicia, California 1-800-624-7958 and talk to Dave ( he's one of the chemists). I've had a lot of dealings with Redline , fact is that Tim (president of Redline) sponcors my brother-in-laws race team , Rapp racing. Rapp Racing Engines of Huntington Beach , Ca is also a Redline dealer. The folks at Redline are ready to answer any and all questions.
dD
dD
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,889
Likes: 21
From: Olathe, Kansas
Just call Redline Oil main office in Benicia, California 1-800-624-7958 and talk to Dave ( he's one of the chemists). I've had a lot of dealings with Redline , fact is that Tim (president of Redline) sponcors my brother-in-laws race team , Rapp racing. Rapp Racing Engines of Huntington Beach , Ca is also a Redline dealer. The folks at Redline are ready to answer any and all questions.
dD
dD
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