Best oil for Truetrac and Sure-Trac?

[DaveBob]

I am installing a brand new third member, stuffed with 3.91 gears and a Doctor Diff Sure-Trac limited slip unit. Doctor Diff and Eaton recommend non-synthetic gear lube, without any friction modifier. Doctor Diff likes 85W140 (but says that 80W90 is okay to use) and Eaton likes 80W90. I would like to use the 80W90, but can't find any consistent brand or product recommendations. The Eaton website just says non-synthetic 80W90, without friction modifier. The Eaton tech line guy did like the Lucas gear lube, but said that it does have some friction modifier, just not a lot. Other people like the Torco RGO or Shell Spirax, both of which are advertised as not containing any friction modifiers. I understand that if the oil is too slippery, you get less bias / lock up. This can happen with synthetics or with friction modifier. Some gear lubes are better than others for quiet operation, too.

So, what is the best 80W90 to use with the Sure-Trac or Truetrac units?

 

[moparleo]

The experts ( people that make and/or install those units by the 100's and thousand's ) already told you. What is the answer that YOU want ? You have more trust in someone you don't know has any real expertise at differentials?
If you end up having a problem because you used something other than the makers recommend, who is going to back your claim ?
Just wondered...

 

[DaveBob]

The experts ( people that make and/or install those units by the 100's and thousand's ) already told you. What is the answer that YOU want ? You have more trust in someone you don't know has any real expertise at differentials?
If you end up having a problem because you used something other than the makers recommend, who is going to back your claim ?
Just wondered...

Leo - Had you read my post more closely, you would have noted that the person with whom I would make any warranty claim (Doctor Diff) declined to recommend any brand of oil, only the type of oil, non-synthetic, 80W90, and my post specifically asks for brand recommendations within this description. Therefore, any brand recommendation made would not contradict the maker's recommendation. Lastly, the Eaton design is similar but not the same, and is mentioned only as reference. The Eaton website makes no brand recommendation, either, only type. And, the Eaton tech line personnel, who are not installers, have recommended various brands this year, depending on when you call and with whom you speak. Even then, any brand recommended by any of the Eaton tech line people would not contradict the recommendation of the person with whom I would make any claim. - DB

 

[Chryco Psycho]

I have usually used Castrol

 

[moparleo]

As you know the manufacturers have to make their products to a standard or specification. Oils for example have API ratings. Branding vs the product itself would just be personal preference. 20 guys will give you 20 different recommendations based on what they use/have tried. An individual will have limited experience with anything as opposed to a mfg/supplier who deals in high qtys. 100's or 1,000's . not just a few cars. As long as it is a quality product, regardless of name it will perform up to its rating. What brand would make you happy ? I bet you have one in mind and just wondered how many others agreed. Back to your original question. just personal preference. Valvoline, Pennzoil, Castrol, Mobil, Quaker State etc.. all have their fans, they all work. Can't go wrong with a major brand.

 

[DaveBob]

As you know the manufacturers have to make their products to a standard or specification. Oils for example have API ratings. Branding vs the product itself would just be personal preference. 20 guys will give you 20 different recommendations based on what they use/have tried. An individual will have limited experience with anything as opposed to a mfg/supplier who deals in high qtys. 100's or 1,000's . not just a few cars. As long as it is a quality product, regardless of name it will perform up to its rating. What brand would make you happy ? I bet you have one in mind and just wondered how many others agreed. Back to your original question. just personal preference. Valvoline, Pennzoil, Castrol, Mobil, Quaker State etc.. all have their fans, they all work. Can't go wrong with a major brand.

You would lose that bet. I have four in mind, three of which I have never used before. And, as you can see, only one person had the courtesy to answer.

 

[DaveBob]

I have usually used Castrol

Thank you for your response. Which unit are you running, the Truetrac or Sure-Trac? If you have a manual trans, any noise on coasting with the clutch in?

 

[Mopar Nut]

This is what Strange sent with my rear.