Red Line 75W90, 1.9k mi OCI, 93k mi, Cadillac CTS-V

[Emperors6]

All mileage is in kilometers not miles.

Notes from oil slip: "Had it in for a few months of normal street use. Replaced thermal activation sensor in rear diff cooler and took opportunity to sample. Actually, left most of the fluid in there."

Previous fill was Fuchs Sintopoid.

 

[Gasbuggy]

ha, interesting. These diffs are really hard on oil. Do you have any noise coming from yours? I change mine every 9,000 miles or so. I have Mobil 75w90LS in there right now.

 

[Emperors6]

Next UOA on the diff was better (per km). However, I have heard no noise from mine. What kind of noise do you hear from yours and when is it easier to hear?

 

[Gasbuggy]

My car has low miles and is silent but I've heard others going bad and they are usually the noisiest on deceleration

 

[Emperors6]

Got it. I've had no issues with RL 75W90 so I'll stick with it. As you can see, I've changed the diff fluid pretty often. I'll try to extend the OCI and see how it goes.

 

[Gasbuggy]

Originally Posted by Emperors6
Got it. I've had no issues with RL 75W90 so I'll stick with it. As you can see, I've changed the diff fluid pretty often. I'll try to extend the OCI and see how it goes.



Is that the Red Line "shockproof"

edit: Just saw the other thread, yes. I was considering running that or AMS OIl next time.

 

[Emperors6]

No, just regular 75W90. I did use ShockProof before I added a cooler to the diff. However, I stopped afterwards since Red Line says about Shockproof: "Avoid use with pumps, coolers, and filters as unique medium and affinity for metal can cause clogging."

 

[MolaKule]

Originally Posted by Emperors6
No, just regular 75W90. I did use ShockProof before I added a cooler to the diff. However, I stopped afterwards since Red Line says about Shockproof: "Avoid use with pumps, coolers, and filters as unique medium and affinity for metal can cause clogging."



The reason they state that for Shockproof is because the load and type of calcium they use will clog up pumps, coolers, and filters.

 

[Emperors6]

Got it. Thanks!

 

[spiderbypass]

Would you consider redline 75w110 which might give you higher film strength and still have good cold flow. I found it interesting that the Redline 75w110 has a lower Brookfield viscosity 80000 compared with 112000 for the 75w90.

 

[MolaKule]

Originally Posted by spiderbypass
Would you consider redline 75w110 which might give you higher film strength and still have good cold flow. I found it interesting that the Redline 75w110 has a lower Brookfield viscosity 80000 compared with 112000 for the 75w90.


Yes, for most rear differentials i prefer a 75W110 and some of those that come to mind could be either

Amsoil 75W110 OR

Red Line 75W110

 

[Lowflyer]

Yep (@MolaKule) But Brookfileds of 75W-110 are littlebit to much for me. I have 2017 mix Syntrax 75W-90 and 75W-140 in ~ 70:30, in angle gear and diff.

Amsoil… For which cars or applications are severegear made? I ask more times Amsoils support for recommendations, but rhey never says: Sure, use also severegear if you like it.