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

**quickster2** · 01-23-2022

When I had my GEN IV it was suggested by the Engineer's to use the GEN V fluid for reduced NVH. I wonder if you can use the original GEN IV fluid with modifier in a GEN V? I recall also being told that the fluids that say LSD or similar do not have the correct amount of modifier. Never had a discussion about how much modifier 1 might add to "regular" diff fluid.

**Norwegian** · 01-27-2022

Thanks!
Just spoke with my local MB dealer, they have the correct one in 0,5 bottles.

I have to say, this forum is a lifesaver living where I do!

**Steve-Indy** · 01-27-2022

Happy to hear that you found the right fluid !!

**Steve-Indy** · 01-22-2023

UPDATE ON THE GEN V Differential Fluid:

As many of you know, CJDR dealers no longer carry the Castrol Syntrax diff fluid previously supplied under a MOPAR label.

The correct fluid has been carried by Mercedes dealerships as noted above...Castrol Syntrax Limited Slip 75W-140.

I have recently "heard" that the Syntrax is being replaced at Mercedes dealerships by Castrol Transmax Limited Slip LL 75W-140. This is supposedly approved for the same cars as the Syntrax...AMG, BMW M, and Nissan GT-R.

I have not had a chance to confirms this just yet...but, I wanted to warn the group that a product change may be happening. If YOU have better intel, please share it here.

Stay tuned.

**BSLSK** · 01-24-2023

Thanks for sharing.

**ViperGeorge** · 01-24-2023

Originally Posted by Steve-Indy

UPDATE ON THE GEN V Differential Fluid:

As many of you know, CJDR dealers no longer carry the Castrol Syntrax diff fluid previously supplied under a MOPAR label.

The correct fluid has been carried by Mercedes dealerships as noted above...Castrol Syntrax Limited Slip 75W-140.

I have recently "heard" that the Syntrax is being replaced at Mercedes dealerships by Castrol Transmax Limited Slip LL 75W-140. This is supposedly approved for the same cars as the Syntrax...AMG, BMW M, and Nissan GT-R.

I have not had a chance to confirms this just yet...but, I wanted to warn the group that a product change may be happening. If YOU have better intel, please share it here.

Stay tuned.

How fast will Mercedes change to the new fluid? Can you still get the old stuff at their dealerships?

**ViperGeorge** · 01-24-2023

Is this the right stuff? Castrol Gear Oil 75W140 SYNTRAX LONGLIFE - 558.00.97. I may hit a Mercedes dealer or two to see if they have it but want to make sure I'm looking for the right stuff.

**Steve-Indy** · 01-24-2023

The correct ORIGINAL differential fluid is called " Castrol Syntrax Limited Slip 75W-140". The label also reads "Axle fluid for limited slip differentials".

P.S. George, I texted the photos to your phone of the 500 ml and liter bottles of this fluid to you. There are shots of front and back on the smaller containers.

**ViperGeorge** · 01-24-2023

I just bought 6 bottles of Castrol TRANSMAX Limited Slip 75W-140 gear oil from my local Mercedes dealer. Under the 75W-140 on the bottle it says "Limited Slip Axel Fluid". On the back it states "API GL-5-Approval 235.61**, ZF TE ML 05C 12D, 16G, 18,21C*** BMW LS Rear Axels; Recommended for use in Nissan GTR limited slip rear axels. *SAE Class according to J306 pre 1998 ** (MP part number A 001 989 52 03 10) ***(DE01 ZF002141)"

The parts guy said TRANSMAX has replaced Syntrax. Here are photos.
IMG_4861.jpg
IMG_4862.jpg

Notice that the part number is the same as shown in post #93 for the Syntrax.

**Steve-Indy** · 01-24-2023

Good show, George !!

**awhit17** · 01-26-2023

As another FYI, the Liqui Moly 75-140 gear oil is specifically designed to suit applications that need SAF-XJ friction modifier, aka our Visco-lok. It is a great and easily available substitute.

**Nth Viper** · 01-26-2023

Originally Posted by awhit17

As another FYI, the Liqui Moly 75-140 gear oil is specifically designed to suit applications that need SAF-XJ friction modifier, aka our Visco-lok. It is a great and easily available substitute.

This is what I settled on, since I couldn't locate any Mopar (reasonably priced) or Castrol Syntrax Limited Slip (anywhere). I did notice after about 2k miles some serious NVH around bends at highway speeds. Even a TT Viper next to me heard it over their car. Not sure if that is this fluid, or my aggressive driving. No noise unless laying into it around corners. I'm going to change to Castrol Transmax and see if the noise is still around.

**awhit17** · 01-26-2023

Well it sounds like the noise is when the diff is locking up some, which would point to it potentially being solved by the fluid....Dang. I have not had issues with my car but I have also not driven it hard since making the switch.

**ek1** · 01-26-2023

Sooooo....since the original fluid has been discontinued, what is my Viper tech at the Dodge dealer is going to use to do a fluid change for a Gen 5 diff later this year?

**ViperGeorge** · 01-26-2023

Originally Posted by ek1

Sooooo....since the original fluid has been discontinued, what is my Viper tech at the Dodge dealer is going to use to do a fluid change for a Gen 5 diff later this year?

The same fluid is available at your local Mercedes dealer. The name has changed from Syntax to Transmax but the part number is the same. It will come in a Castrol gold color container. See post #109. You will need to take the fluid to your Dodge dealer.

**ek1** · 01-26-2023

Originally Posted by ViperGeorge

The same fluid is available at your local Mercedes dealer. The name has changed from Syntax to Transmax but the part number is the same. It will come in a Castrol gold color container. See post #109. You will need to take the fluid to your Dodge dealer.

Yup, I saw that post and I already ordered 6 cans of the MB part yesterday. I was just wondering what happens if someone shows up at a Dodge dealer wanting to do a diff fluid change on their Viper.

**Steve-Indy** · 01-26-2023

ek1, there is an excellent chance that the dealer will try to give you the Gen I-IV diff fill...and, likely from the bulk source. This has been a problem from the very beginning of the Gen V's for all of the reasons I listed when I started this post.

My advice is to take your own fluid...just as you plan.

**ek1** · 01-26-2023

Originally Posted by Steve-Indy

ek1, there is an excellent chance that the dealer will try to give you the Gen I-IV diff fill...and, likely from the bulk source. This has been a problem from the very beginning of the Gen V's for all of the reasons I listed when I started this post.

My advice is to take your own fluid...just as you plan.

Now I'm wondering what I got in my car. I got a brand new rear diff under warranty in Sept '21 and it's kind of noisy....nothing crazy, just a little occasional rattle. I think I'll ask the tech to do a test drive when I take it in for an oil change in a few months. Maybe they didn't have the right fluid and put something else in.

No additives required for this one, correct?

**Steve-Indy** · 01-27-2023

No additive necessary with the correct Gen V fluid.

**quickster2** · 01-27-2023

Originally Posted by ek1

Now I'm wondering what I got in my car. I got a brand new rear diff under warranty in Sept '21 and it's kind of noisy....nothing crazy, just a little occasional rattle. I think I'll ask the tech to do a test drive when I take it in for an oil change in a few months. Maybe they didn't have the right fluid and put something else in.

No additives required for this one, correct?

The new differentials came right from Dana with the fluid already in them. It would be worth checking with the dealer to see if that was the case for your warranty replacement.

**mblgjr** · 01-29-2023

Originally Posted by ek1

Sooooo....since the original fluid has been discontinued, what is my Viper tech at the Dodge dealer is going to use to do a fluid change for a Gen 5 diff later this year?

Nothing; you're going to supply them with the correct fluid

right

**ViperGeorge** · 01-29-2023

I ordered the diff fluid from the link in post 93. When you look at the link it shows Castrol Syntrax but when it arrived it was Transmax. Same part number so I'm sure it is just a new name for the old fluid.

**Steve-Indy** · 01-29-2023

From the Castrol website:

"Transmax Limited Slip LL 75W-140 Axle Fluid for Limited Slip Differentials

Description: Castrol Transmax Limited Slip LL 75W-140, formulated with Smooth Drive TechnologyTM, is a full synthetic hypoid gear oil formulated for use in both conventional and limited slip differentials. It has demonstrated outstanding performance in competition vehicles employing limited slip differentials. It is approved for use in the high performance BMW-M Series and Mercedes Benz AMG limited slip differentials.

Advantages: Reduces noise and vibrations in the axle. Excellent shear stability maintaining performance over the life of the lubricant. Exceptional stability at high temperatures extending the life of lubricant and axle. Effective wear resistance ensures protection under high loads and prevents damage to components. Very good low temperature fluidity properties increases protection at start up."