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

[Martin]

Sorry that I didn't read through all of the threads... Is this stuff good for the Gen II diffs, too? I'd like to standardize on one fluid. My Gen II diff whined like crazy, so I swapped in Red Line fluid which sorted it out completely. But, if there's something out there that will fix that problem, I'm going to stock up on it. I might even use it in my Rubicon 392 diffs if it meets those specs. The Rubicon diffs get crazy hot....

[Steve-Indy]

Martin, the answer is...I don't know.

If you read the communication that I quoted in post #1 of this thread. mention was made by THE credible source that Gen IV differentials could benefit from the Syntrax Limited Slip 75W-140 fluid...with no mention being made concerning the Gen I, II, or III differentials.

A Viper Tech should be able to answer your question.

In my own situation, I use the recommended fluids per each individual vehicle.

[Meteoro]

do you guys use any tread sealer when putting back the plugs?

[mblgjr]

do you guys use any tread sealer when putting back the plugs?

I used a typical liquid teflon pipe sealant (non hardening). Permatex offers it. Don't put it on like the first 3-threads, but otherwise it makes a nice seal.

[mblgjr]

Kind of a poor choice of names, if I saw "Transmax" on the shelf, I would think it's gear oil for manual transmissions.

I agree but there can be some odd product relabeling from the European/World market sometimes. Their marketing department doesn't always jive with what we're used to.

[finalleaf]

just ordered off ECS at about $23/500ml, gonna assume the local mercedes dealership will be more expensive

also considered motul/redline which my shop has and say they're "compatible" but i dont see anything in the forums about them and I dont want to be the guinea pig :P

[Steve-Indy]

"Change is the only constant in life"...Heraclitus (Greek Philosopher)

IMPORTANT UPDATE/WARNING on the EVOLUTION and AGE of Gen V Viper Differential Fluids

For the early history of this specific fluid, see post # 1 in this 2015 thread:

https://driveviper.com/forums/thread...s-a-Gen-IV-tip

Keep in mind that MOPAR stopped supplying their branded version of the Castrol Syntrax Limited Slip 75W-140 somewhere around 2018-2019. It was NOT listed in the pdf version Chrysler/MOPAR "2020 Vehicle Lubricant & Chemical Catalog". While a few bottles existed at some dealerships, many of us had already started buying the Castrol version directly from Mercedes dealerships that came in metric equivalents of pints and quarts...at an excellent price. The pint size (actually 500 ml) has a very handy extendable spout. INTERESTINGLY, this Castrol Syntrax Limited Slip 75W-140 has now disappeared from many Mercedes dealerships...and, from Castrol's online product list.

The latest Castrol differential product for Mercedes AMG's, BMW M series, Nissan GTR's, and PRESUMABLY Gen V Vipers that supersedes the Syntrax Limited Slip 75W-140 is Castrol Transmax Limited Slip LL 75W-140. The container looks like the Syntrax...with the same cool spout on the 500ml bottles which sell for $26.75 apiece retail (tax included) here in Indy today. While it puzzles me that Castrol picked the name "Transmax" for a differential lubricant, the Castrol Tech Supporyt Help Line in the UK who I contacted by telephone TODAY assured me that the Transmax Limited Slip LL 75W-140 is an IMPROVED lube for our differentials.

IMPORTANT RECENT DISCOVERY by Viper Wizard Chuck Tator (Owner of Tator's Garage...Head of VOA Tech Committee):
While preparing to use some of the original MOPAR "SAE75W-140Gear and Axle Lubricant" in a Gen V Viper differential, Chuck noticed that this "fluid" had turned to "jello", with lumps, and a gritty precipitate was also noted. THIS IS MOST ALARMING as many (most ??) folks that I know generally squeeze these bottles by hand to fill the differentials directly without the potential mess of using a transfer pump. So, WHO would know the status of the fluid ?? Unfortunately, the fluid that Chuck had purchased from a dealership had no discernible date codes...so the actual age was/is unknown. Chuck got rid of the whole lot.

When doing a little lube research, I found that a general rule of thumb for these fluids is that they have about a 5 year shelf life. Fluid and lube EXPERT Tom Hayden was kind enough to give me a short tutorial on these types of products...noting that this is complex chemistry. Tom MAY get in on this thread in the near future...and if he does, please LISTEN to his advice and explanations. By the way, during my conversation with Castrol UK today, they indeed confirmed the 5 year shelf life of these products...noting that once the container has been opened and resealed, it must be used within 2 years or discarded.

WITH the background information updated above, I PERSONALLY would RECOMMEND that Gen V owners use only Castrol Transmax Limited Slip LL 75W-140 purchased at one's local Mercedes dealership...paying strict attention to the date code on the bottle before purchase and use.

If you have a supply of the older Syntrax with date codes less than 5 years, I would only use it after decanting it (like a bottle of wine) into a clean, clear container to check for separation of the contents, thickening of the fluid, and/or precipitation of components .

If you have some of the discontinued MOPAR fluid, I would NOT USE IT and would merely discard it in the appropriate fashion.


FINALLY, I would add a "pitch" for joining and/or renewing one's membership in the Viper Owners Association with the following question:

Who else is watching out for YOU and YOUR VALUABLE ASP in this important and ever changing arena??

REMEMBER that "It takes a village..."

Respectfully submitted,

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

"YOUR Viper Owners WORKING for YOU !!!

P.S. Updates, corrections, and additional information to this post are ALWAYS WELCOME

[ViperGeorge]

Steve, thanks for the update. I had purchased Transmax from my local Mercedes Dealer and it has the same part number as the older Syntrax fluid. I really need to get the diff fluid in my 14 GTS changed and my 08 Vert. Does the 08 take the same fluid, the Transmax?

[Steve-Indy]

First off, George, THANKS for your input on this and your posted photos of the new Transmax as found on page #5 of this thread. You are a major contributor to the Viper cause !!

The answer to your question about using the Syntrax Limited Slip 75W-140 in Gen IV differentials was answered by "THE Man" as covered in this quote from post #1:
"... 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...."

[ViperGeorge]

First off, George, THANKS for your input on this and your posted photos of the new Transmax as found on page #5 of this thread. You are a major contributor to the Viper cause !!

The answer to your question about using the Syntrax Limited Slip 75W-140 in Gen IV differentials was answered by "THE Man" as covered in this quote from post #1:
"... 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...."

Thanks, I actually just finished reading that post. After asking the question I figured the answer must be in this thread somewhere so I started from the beginning. I was actually just going to edit my post to remove the question but you beat me to it.

[Steve-Indy]

By the way, in my long post above, I typed "...noticed that this "fluid" had turned to "jello"," when I MEANT to type "jelly". As I recall, Chuck further stated that this fluid was sticky.