Dino or Synthetic for Differentials?

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I just read a post in this forum where a very knowledgeable person said that the "Golden Rule was to use Dino in the Rear." That really got my attention. I want to know more about this. Anybody got time for their input? I have a teachable spirit....
 
I used dino on my diff because it cost half as much. It works fine. I don’t see much of a need for synthetic unless you pull heavy loads constantly.
 
I'm being serious, not smart aleck. Does that make it the "golden rule"? Are there chemical properties in dino that make it superior in a rear end?
 
I have never heard about the Golden Rule for differential fluids. However, I would never use anything but a synthetic in a differential in a cold weather climate. This isn't the video I was looking at, but it demonstrates the difference between a dino and a synthetic diff fluid in cold weather. While the synthetic is a 75W and the dino is an 80W, the dino still doesn't offer flow like it should, even when it reaches the temperature where it is supposed to start working.

https://www.youtube.com/watch?v=fuwunDgEVMs
 
Originally Posted By: LoneRanger
Dino (conventional) adheres to the gears better than synthetic.
Based upon what? Any factual information to share to substantiate this statement?
 
IMO, if it's a regular use rear-end and not for towing or hauling heavy loads I would use conventional at the right viscosity recommended by the manufacturer for the climate it's operated in. Otherwise I would go to synthetic for higher heat applications.

Dino does not "adhere" better to anything unless you are talking about deposits in an engine.
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Synthetic “adheres” to that little book that comes in the glove box… some may have noticed OEM’s spec synthetic in gear sets before it became more common in the ICE …
 
It boils down to a.) following your owners manual and b.) personal preference.

That said, I wouldn't think dino vs. synthetic would be backwards compatible.
 
Never heard of that golden rule. Currently running Castrol Syntrax 75w90 Synthetic in an 01 Tacoma with OM spec of 80w90 dino. Purchased on AZ close out <$5 a bottle. Guess that means that's one 'golden rule' I won't be observing.
 
Originally Posted By: 69GTX
Some differentials require conventional....such as Auburns with cone clutches.


You made BITOG's first frog hair splitting post of the day.
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How many members does this post apply to anyways?
 
Depending on the type of rust bucket you're servicing... "The Best or its pointless" <-- consider that the Platinum Rule.
 
It's the KV@40*C that matters.
Oh yes, dino has higher pressure-viscosity coefficient than synthetics god in PAO's providing thicker MOFT for stronger components protection as a primary function of lubrication, all other parameters are secondary.
 
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Originally Posted By: 2015_PSD
Originally Posted By: LoneRanger
Dino (conventional) adheres to the gears better than synthetic.
Based upon what? Any factual information to share to substantiate this statement?


Yes. Group I and II oil has better polarity. Group III, which majority of "synthetics" are today, has poor polarity for metal cling as compared to Grp I and II. Known fact and common knowledge on here.
 
Is it not the case that many fairly recent Chrysler products call for conventional diff lubes?

Also, for when things get older and people want to go for the X-140 weight gear lubes, is there a conventional which goes that high?
 
In farm equipment with gear boxes that we see that sit for 6 to 9 months at a time that have syn gear oil in them. You can see the gears will have rust on them from the oil line and up. Never have seen that with dino oil in them. The syn oil drains off of them completely with that much sit time and they have no protection.
 
Originally Posted By: rideahorse
In farm equipment with gear boxes that we see that sit for 6 to 9 months at a time that have syn gear oil in them. You can see the gears will have rust on them from the oil line and up. Never have seen that with dino oil in them. The syn oil drains off of them completely with that much sit time and they have no protection.

That's an interesting observation with dino !
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Originally Posted By: LoneRanger
Originally Posted By: 2015_PSD
Originally Posted By: LoneRanger
Dino (conventional) adheres to the gears better than synthetic.
Based upon what? Any factual information to share to substantiate this statement?
Yes. Group I and II oil has better polarity. Group III, which majority of "synthetics" are today, has poor polarity for metal cling as compared to Grp I and II. Known fact and common knowledge on here.
How does that equate to less wear or longer oil life?
 
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