Me too !!!
Differential Fluid, which do you use?
Racer
Joined: Apr 2004
Posts: 293
Likes: 0
Originally Posted by Roadking
Check out this web site. Contact Subdriver on the forum to order. 
http://www.c66racing-synthetics.com/...ns/G2039PB.htm
http://www.c66racing-synthetics.com/...ns/G2039PB.htm
Team Owner
Joined: May 2004
Posts: 26,345
Likes: 231
From: SoCal
Originally Posted by DynoTech Engineering
We've been asked to chime in here to set things straight regarding our differentials and what lubricants to use with them. Please copy-paste-print off or what-ever to keep as a data reference, as we've covered this very same topic with similar answers on this board about 4-5 times in the past now.
Our Stage 2-5 differentials utilize a heavy duty clutch pack design w/ heavy duty clutch pack pre-load springs that are exclusive to our engineering design. Therefore, in order for our differentials to operate properly in a wide variety of performance conditions/applications, we require the use of Redline brand 75w/140 fully synthetic differential lubricant which has approx. 4% of Redline brand fully synthetic limited slip additive already blended in at the Redline Lubricants factory. We add an additional ounce of Redline fully synthetic limited slip additive to each bottle here at DTE for a total blend of 13%, that supports our heavy duty clutch pack design. We carry this blend here..
DO *NOT* use GM L.S.A. additive in *ANY* of our 75w/140 lubricants at all, in any capacity what-so-ever. That was fine with the old 75w/90 we used to use, but *NOT* for the new 75w/140 blend. If you choose to do this, we can assure you with 100% certainty that you *WILL* have clutch pack problems of some sort.....
If you have a stock differential w/ stock clutch packs or our Stage 1 model differential, we recommend the use of the standard 4% blend of Redline brand 75w/140 lubricant and pour in stright from the bottle. We also carry this blend here..
Thanks folks.
Best Regards,
DTE
Our Stage 2-5 differentials utilize a heavy duty clutch pack design w/ heavy duty clutch pack pre-load springs that are exclusive to our engineering design. Therefore, in order for our differentials to operate properly in a wide variety of performance conditions/applications, we require the use of Redline brand 75w/140 fully synthetic differential lubricant which has approx. 4% of Redline brand fully synthetic limited slip additive already blended in at the Redline Lubricants factory. We add an additional ounce of Redline fully synthetic limited slip additive to each bottle here at DTE for a total blend of 13%, that supports our heavy duty clutch pack design. We carry this blend here..
DO *NOT* use GM L.S.A. additive in *ANY* of our 75w/140 lubricants at all, in any capacity what-so-ever. That was fine with the old 75w/90 we used to use, but *NOT* for the new 75w/140 blend. If you choose to do this, we can assure you with 100% certainty that you *WILL* have clutch pack problems of some sort.....
If you have a stock differential w/ stock clutch packs or our Stage 1 model differential, we recommend the use of the standard 4% blend of Redline brand 75w/140 lubricant and pour in stright from the bottle. We also carry this blend here..
Thanks folks.
Best Regards,
DTE
Do you feel that stock GM fluid is insufficient for heavy duty use ???
Thanks,
DH
Collections Hold
Joined: Aug 2002
Posts: 2,899
Likes: 6
From: Fort Wayne Indiana
Originally Posted by Dirty Howie
Would you care to make a recommendation for a stock Z06 rear gears ???????
Do you feel that stock GM fluid is insufficient for heavy duty use ???
Thanks,
DH
Do you feel that stock GM fluid is insufficient for heavy duty use ???
Thanks,
DH
We still see folks insist on using it for HP applications and we just cringe when we see that, knowing that the differential is screaming for dear life back there.... It might be fine for a 100% stone-stocker car, but that's about it and we wouldn't suggest that lube for *anything* other than grocery-getting type driving...ever.
To each his own though.
DTE
Racer
Joined: Jan 2006
Posts: 265
Likes: 1
From: OKC OK
i had 90,000 on my vette when i bought it...and no record of fluid change...is it okay to change differential fluid w/that many miles? i heard ..dont change trans fluid ..but wasnt sure about differential fluid
Team Owner
Joined: May 2004
Posts: 26,345
Likes: 231
From: SoCal
Originally Posted by DynoTech Engineering
We use Redline 75w/140 straight out of the bottle in stock differentials around here and you don't really want to know what we think about that over-priced, stinky snot GM calls differential lubricant... We've tested that lube in the past for HP use w/ added power, racing applications, etc. and it failed miserably in every instance for the areas of use that these HP differentials typically live in.
We still see folks insist on using it for HP applications and we just cringe when we see that, knowing that the differential is screaming for dear life back there.... It might be fine for a 100% stone-stocker car, but that's about it and we wouldn't suggest that lube for *anything* other than grocery-getting type driving...ever.
To each his own though.
DTE
We still see folks insist on using it for HP applications and we just cringe when we see that, knowing that the differential is screaming for dear life back there.... It might be fine for a 100% stone-stocker car, but that's about it and we wouldn't suggest that lube for *anything* other than grocery-getting type driving...ever.
To each his own though.
DTE
I have fresh Stinky Smelly Stuff in there right now as they just redid my left side plate seal for the second time. Not sure if it was coincidental but shorty after draining the GM SSS and replacing with Mobil 1 gear oil in started leaking.I do track my car and will follow your advise...
DH
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
Burning Brakes
Joined: May 2005
Posts: 992
Likes: 2
From: Granville Ohio
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'17-'18-'19-'20-21
The correct answer to the question is What DynoTech Engineering says. They do this for a living and have much more data and experience than most do. Redline 75 -140 it will be.
Last edited by OhioDave; Aug 19, 2006 at 08:12 AM.
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,886
Likes: 20
From: Olathe, Kansas
Originally Posted by dcblackc5
The correct answer to the question is What DynoTech Engineering says. They do this for a living and have much more data and experience we do. Redline 75 -140 it will be.
For strictly (sometimes spirited) street driving, do I need the 75-140?
Burning Brakes
Joined: May 2005
Posts: 992
Likes: 2
From: Granville Ohio
St. Jude Donor '06-'07-'08-'09-'10-'11-'12-'13-'14-'15-'16'17-'18-'19-'20-21
Originally Posted by Bills03Coupe
75-140W? Everything I've read has been to use the 75-90w.
For strictly (sometimes spirited) street driving, do I need the 75-140?
For strictly (sometimes spirited) street driving, do I need the 75-140?
Collections Hold
Joined: Aug 2002
Posts: 2,899
Likes: 6
From: Fort Wayne Indiana
Oversimpplified~
We used to use the 75w/90 in our HP differentials, as well as in stock differentials also, but it just wouldn't last for the long term in high performance applications. However, through testing, we found that the higher viscosity 75w/140 was quite a bit more tolerant to thermal break down and remained a bit thicker in high performance applications that generated a lot of driveline heat- from internal friction from the differential itself, heat transfer from the transmission and from radiant heat from the two super-heated exhaust pipes that run right next to either side of the differential.
We've found the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140. That's why we switched.
Hope that helps some and there are more threads on this subject around here that we go into more depth with this topic also.
DTE
We used to use the 75w/90 in our HP differentials, as well as in stock differentials also, but it just wouldn't last for the long term in high performance applications. However, through testing, we found that the higher viscosity 75w/140 was quite a bit more tolerant to thermal break down and remained a bit thicker in high performance applications that generated a lot of driveline heat- from internal friction from the differential itself, heat transfer from the transmission and from radiant heat from the two super-heated exhaust pipes that run right next to either side of the differential.
We've found the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140. That's why we switched.
Hope that helps some and there are more threads on this subject around here that we go into more depth with this topic also.
DTE
Last edited by DTE Powertrain; Aug 18, 2006 at 04:52 PM.
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,886
Likes: 20
From: Olathe, Kansas
Originally Posted by DynoTech Engineering
Oversimpplified~
We used to use the 75w/90 in our HP differentials, as well as in stock differentials also, but it just wouldn't last for the long term in high performance applications. However, through testing, we found that the higher viscosity 75w/140 was quite a bit more tolerant to thermal break down and remained a bit thicker in high performance applications that generated a lot of driveline heat- from internal friction from the differential itself, heat transfer from the transmission and from radiant heat from the two super-heated exhaust pipes that run right next to either side of the differential.
We've found the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140. That's why we switched.
Hope that helps some and there are more threads on this subject around here that we go into more depth with this topic also.
DTE
We used to use the 75w/90 in our HP differentials, as well as in stock differentials also, but it just wouldn't last for the long term in high performance applications. However, through testing, we found that the higher viscosity 75w/140 was quite a bit more tolerant to thermal break down and remained a bit thicker in high performance applications that generated a lot of driveline heat- from internal friction from the differential itself, heat transfer from the transmission and from radiant heat from the two super-heated exhaust pipes that run right next to either side of the differential.
We've found the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140. That's why we switched.
Hope that helps some and there are more threads on this subject around here that we go into more depth with this topic also.
DTE
1st Gear
Joined: Aug 2006
Posts: 1
Likes: 0
Red-Line
I spoke with Dave at Red-Line. He recommended the 75W-90 for the Differential. It has the friction Modifier package in it. No issues at all.
I put the D4 ATF in the transmission. It had Royal Purple in it and used to be difficult to get into 1st at a stop light but with the Red-Line this problem has virtually gone away! The problem is now it wants to grind during the 1-2 shift. Is it possible that these synthetics are just too slippery? I talked with Red Line agian and they said that I might try the MTL instead of the D4-ATF. They said that they recommed using that for racing and high load applications. Any thoughts? This is driving me crazy! This is my first Corvette and I love the car but I have never experienced such shifting issues in any car and I have several (6) high performance sports cars including Porsches, Mazdas and a Pantera. Your advise would be appreciated!
Thanks!
Tom
I put the D4 ATF in the transmission. It had Royal Purple in it and used to be difficult to get into 1st at a stop light but with the Red-Line this problem has virtually gone away! The problem is now it wants to grind during the 1-2 shift. Is it possible that these synthetics are just too slippery? I talked with Red Line agian and they said that I might try the MTL instead of the D4-ATF. They said that they recommed using that for racing and high load applications. Any thoughts? This is driving me crazy! This is my first Corvette and I love the car but I have never experienced such shifting issues in any car and I have several (6) high performance sports cars including Porsches, Mazdas and a Pantera. Your advise would be appreciated!
Thanks!
Tom
Race Director
Joined: May 2000
Posts: 14,542
Likes: 5
Tom --
Great advice here on the foum, but why not just use what the manufacturer recommends?
GM is willing to stand behind what they recommend by warranting the car, and will also void a warranty if they find something in the car that they do not recommend.
Now, that's commitment.
Go with the baseline first, then start to add all the colored stuff -- red, purple, or soil.
I've had my 2000 MN6 for six years and almost 75,000 miles. No problems on the differential, transmission, engine, or the clutch. Always used the cheapest that met GM specs.
I saved money, and the car loves it.
Great advice here on the foum, but why not just use what the manufacturer recommends?
GM is willing to stand behind what they recommend by warranting the car, and will also void a warranty if they find something in the car that they do not recommend.
Now, that's commitment.
Go with the baseline first, then start to add all the colored stuff -- red, purple, or soil.
I've had my 2000 MN6 for six years and almost 75,000 miles. No problems on the differential, transmission, engine, or the clutch. Always used the cheapest that met GM specs.
I saved money, and the car loves it.
Last edited by EHS; Aug 19, 2006 at 06:32 AM.
Burning Brakes
Joined: Oct 2004
Posts: 792
Likes: 19
From: ME
Goodness Gracious!!! To each ones own opinion on the diff fluid (I run the GM fluid w/additive) but I am aghast that nobody has mentioned that when you change the diff fluid, to PROPERLY SET THE FLUID LEVEL SO IT DOESN'T LEAK you need to road test the car and get the diff to normal operating temp and then open the fill plug and drain out what you might have overfilled. Yes - per C4C5 specialist from "corvettemechanic" and also from GM techs I've met you MUST set the diff fluid at operating temperature. If it's overfilled it spits out the vent. Trust me, I changed my left axle seal thinking that was the problem and still didn't set the diff fluid level properly and my leak came right back! 
There. I speak the truth!
There. I speak the truth!
Team Owner
Joined: Jul 2004
Posts: 24,652
Likes: 298
From: NJ
St. Jude Donor '05-'08
Originally Posted by DynoTech Engineering
Oversimpplified~
We used to use the 75w/90 in our HP differentials, as well as in stock differentials also, but it just wouldn't last for the long term in high performance applications. However, through testing, we found that the higher viscosity 75w/140 was quite a bit more tolerant to thermal break down and remained a bit thicker in high performance applications that generated a lot of driveline heat- from internal friction from the differential itself, heat transfer from the transmission and from radiant heat from the two super-heated exhaust pipes that run right next to either side of the differential.
We've found the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140. That's why we switched.
Hope that helps some and there are more threads on this subject around here that we go into more depth with this topic also.
DTE
We used to use the 75w/90 in our HP differentials, as well as in stock differentials also, but it just wouldn't last for the long term in high performance applications. However, through testing, we found that the higher viscosity 75w/140 was quite a bit more tolerant to thermal break down and remained a bit thicker in high performance applications that generated a lot of driveline heat- from internal friction from the differential itself, heat transfer from the transmission and from radiant heat from the two super-heated exhaust pipes that run right next to either side of the differential.
We've found the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140. That's why we switched.
Hope that helps some and there are more threads on this subject around here that we go into more depth with this topic also.
DTE
Race Director
Joined: May 2000
Posts: 14,542
Likes: 5
Originally Posted by DynoTech Engineering
Not even worth addressing.....
DTE
Your "testing" is better than GM's?
Why wouldn't GM recommend 75w/140 like you do, if you've found that: "the differentials to run quieter, a bit cooler and the lubricant quality to remain more constant in quality over a greater amount of miles/time with the use of 75w/140."