FINAL answer on Gen V Viper Differential lubricant...plus a Gen IV tip...

[Steve-Indy]

OK Viper Owners, here is THE FINAL ANSWER concerning our LONG discussion of the "factory fill" and "service fluid" used in the Gen V Viper differentials. I cannot and will not post the sources of the info contained here...BUT, merely express my personal thanks and appreciation to the kind, interested, "high level professionals" who provided this communication. Thanks are also owed to "lochnessmonster" for calling our collective attention to this situation. You can see this initial discussion in this link: http://driveviper.com/forums/threads...ction-modifier

"The Viper rear axle lube used from 1992 – 2010 (with Dana Trac-Lok and Hydra-Lok differentials) was the corporate ‘standard’ MS-8985 synthetic 75W-140… this was the same generic 75W-140 used in many other Chrysler products. For the Viper, the MS-10111 limited slip additive was also required. Viper fill volume to the bottom of the fill plug is about 48 oz. The factory fill at Dana was pre-blended with friction modifier at 5% by volume. For Service, the 75W-140 and the friction modifier are sold separately and the dealer/customer need to do the mix. The correct friction modifier amount for the Viper axle fill based on the 5% blend is about 2.4 oz. Unfortunately the stuff comes in a 4 oz. bottle I believe, so somewhere along the line, it became popular to put in a full bottle. A little more or less does not cause problems, but the correct amount has always been 5% by volume. Because it was a generic synthetic 75W-140, the MS-8985 fluid came from a variety of fluid suppliers including Shell, Texaco, etc.


Over time and miles, the friction modifier tends to ‘burn off’ and become less effective, causing some chatter when turning or other NVH issues. Usually, a fresh fluid/friction modifier change is sufficient to get things back to normal. The NVH issue became more apparent with the introduction of the Viper GKN Visco Lok differential in 2008. For 2008 – 2010, we lived with the standard 75W-140 fluid because it met all of our durability requirements and was less expensive than other lube alternatives. But we did have more of a friction modifier ‘loss of effectiveness’ issue with the Visco Lok as we got more experience with the new differential. We learned that on some cars, the Visco Lok would tend to make a howl/growl/grind noise when turning at low speed if the friction modifier was used up. So for 2013, we went with the special Castrol SAF-XJ 75W-140 synthetic developed by Castrol and GKN for the Visco Lok. This fluid has a different friction modifier and blend % already mixed for factory fill and Service. No added friction modifier is necessary. It is also recommended that the Castrol SAF-XJ be used for Service of 2008 – 2010 Vipers with the Visco Lok. I do not know if Castrol sells this product under their brand name, but I do know that it is available in a special ‘SRT’ bottle from Mopar. "

NOTE #1: "NVH" as used above in the second paragraph stands for "Noise, Vibration, and Harshness"...standard driveline issues.

NOTE #2: "Castrol SAF-XJ/SAE 75W-140 Synthetic Gear and Axle Lubricant" as listed in the Gen V Owners Manual has been renamed "Castrol Syntrax Limited Slip 75W-140".

The MOPAR part number for this fluid is 68197927AA and, YOU can purchase this at your local Chrysler-Jeep-Dodge-Ram dealership, though they may not have it in stock.

Thanks, again, to All who helped with this issue,

Steve Fess, Membership Coordinator, VOA IN/KY Region, Inc. 317-402-9013

[lochnessmonster]

Wow, nice job Steve! Sorry, I didn't see your request to get in touch with me in the other thread until just now. This is a very comprehensive review of the requirements throughout the years and what is required in our Gen V. Again, way to go! As people start getting to the point where this change is necessary, they'll be good to go.

[Simms]

Good info. Thanks!

[99RT10]

You rock, thanks Steve!! Great info!!!

[Steve-Indy]

Thanks, guys...BUT, it was Tom Sessions who carefully "reached up the line" and obtained this info !! As many of you know, NC Viper Tech Tom has a ton on experience, invaluable connections, and is a man who is very sharing with his time and knowledge. THANKS, Tom !!!

[Rapidrezults]

Thanks to all that participated in gathering this information! Good to have a community like this to get down to the nitty-gritty.

I know I will be changing my diff fluid soon and now it's one less thing to think about.

[SRT BILL]

Great info and thanks to all that worked on this.

[swexlin]

Nice to know! I wrote it down, since I bet most dealers won't even know!

[Viper Specialty]

Excellent write up and explanation! Good info to have.

[viper04]

Steve-Indy
Thanks for the info as always good to know, will be doing one over the winter.

[wrh3]

Just in time for me to dump the factory filled fluids- Thanks!

[rlhay2]

This should be stickied in the Gen IV and Gen V forums.

Thanks for the reasearch!!

[TIME]

Thank you, for providing this info. I am printing it and sticking it in my manual.

[A99SilverACR]

All you can also get this fluid from a local BMW dealer as it is the same service fluid used in the M6...

[AZTVR]

I like seeing this kind of information as it shows why the usage of some other off-the-shelf purple fluid, or soil fluid used by "some friend" may not provide the same results as what the powertrain engineers specified. For better or worse.

[Steve M]

Just did some poking around on the interwebs to see if I could find a better price than the $33/qt Mopar charges for this fluid...looks like you can't buy this fluid in the US outside of a dealership. It is easier to come by across the pond (Europe) though. Not sure how I feel about that...I still have enough Torco gear oil + Mopar friction modifier to change the diff fluid this fall, so I'll probably use that up and re-evaluate in a year or two.

[wrh3]

I found the Castrol Syntrax at https://www.carpartsdiscount.com/dif...ml?3593=545783 , not really any cheaper than at the dealer.

[TA Two Oh]

My local dealership did an Engine Oil and Filter change on my 2015 yesterday, and at my request, also changed the differential fluid. In reviewing my work order, they used the correct lubricant FCA Part # 68197927-AA, which is great. But they also added a friction modifier part # 04318060-AD, and it looks like that was unnecessary since it's already in the diff fluid. I don't care about the cost -it was minimal- but I am wondering if their mistake is bad for the differential. Thoughts?

[SnakeWatching]

Any harm in using the Castrol SAF-XJ for the Gen 2 differential? (so I don't have to mix the 2 parts)

[Steve-Indy]

I did not ask that question...but reading the "word", I would say no harm other than to your wallet. I do not intend to deviate from OEM specs for our Gen I, II, and III Vipers.

[Bill Pemberton]

Great info as always Steve and great to also give Mr. Sessions the thanks he deserves for his perseverance!!

[1of1TA1.0]

How does the Motul Gear Lube stack up to this. I ran Motul in my 08 ACR and never had a problem. I did change it after every other track weekend however.

[EZ 2B Green]

Moderators, can we make this thread a "sticky" so it's easy to find in the future?

[Chorps]

My local dealership did an Engine Oil and Filter change on my 2015 yesterday, and at my request, also changed the differential fluid. In reviewing my work order, they used the correct lubricant FCA Part # 68197927-AA, which is great. But they also added a friction modifier part # 04318060-AD, and it looks like that was unnecessary since it's already in the diff fluid. I don't care about the cost -it was minimal- but I am wondering if their mistake is bad for the differential. Thoughts?

This in the Nissan GT-R manual...granted the differentials are for an AWD computer controlled system, but the principles should be the same. Don't think it would matter much on a street driven Viper but if you are tracking it it might make a difference.

DIFFERENTIAL OIL (front and rear)

Castrol SAF-XJ 75W-140 (100% synthetic oil)

The GT-R uses a 1.5-Way mechanical Limited Slip Differential (LSD) to maximize driving power under many operating conditions. Use the specified differential oil to maximize the perfor- mance of the LSD. Also use the same oil for the front differential.

The use of additives is prohibited.

Using additives or any other than the specified differential oil may cause the oil temperature to increase and the final drive damaged. Also it may cause vibration and adversely the vehicle handling characteristics.

[TA Two Oh]

This in the Nissan GT-R manual...granted the differentials are for an AWD computer controlled system, but the principles should be the same. Don't think it would matter much on a street driven Viper but if you are tracking it it might make a difference.

Thanks. I appreciate your input. Excess heat and/or vibration doesn't sound good. I'll have it changed again.