Manufacturers spend lots of money on engineering. Yes down to the proper lubricants and fluids. As a 4 th. Gen mechanic I recommend following manufacturers reccommendations. For all fluids. Your differential is probably the most overlooked of all fluids. Many manufacturers use vehicle specific fluids.
Spend the couple extra bucks and don't use universal fluids. I'm not an engineer but your auto manufacturer has plenty and they use materials that have specific lubrication requirements
Yes recommended fluids but you also have something else to consider. What year was the recommendation and what grade or classification replaced that product.
Also is there a synthetic that is a direct replacement that has exceeded those previous grades and classification.
The oil recommended for my 85 Pontiac is not the same today as the formulas have changed and there are some better options.
I have a flat tappet cam and the 10w30 oil today is not the same and could damage the cam over time. I have gone to an oil Mobil recommends with greater Zinc and phosphates in the formula recommended for older flat tapper cams.
There is more to consider today than just numbers give when the vehicle was new.
Agree with hyperv6.
Synthetic formulation has also changed a lot over the past few decades. What wasn’t appropriate in the 70’s, 80’s and 90’s is as good, and often better, than what manufacturers recommended in the owner’s manual...as long as it meets API specs and contains any needed modifiers.
Another consideration is availability. Most manuals recommend the manufacturer’s own brand, which usually costs a bit more and may not be as convenient as the local chain parts store. And that can lead to delaying or avoiding the fluid changes all together.
All that said, if the owner doesn’t care to do the requisite research staying with that manual is always the safest bet.
Not a day goes by where someone comments on one of my YouTube videos that I'm an idiot because I'm not using XYZ oil with zinc in my Ford Model A. At least once or twice a week, I get told that I should ONLY run 30 wt. non-detergent, because that's what was in it when they came from the factory.
The fact is, today's worst oil is better than 1929's best oil. Zinc and other additives didn't come on the scene until after the Model A's were long replaced by the flathead V8 cars from Ford. So, in essence, people who chastise me for using the wrong oil in a Model A are just looking for a reason to complain.
My Model A videos have helped a lot of people, and that's why I keep making them. I make videos to help new Model A owners and people thinking about getting a Model A. But still, those rude comments from the "oil nazis" still pop up almost daily, and it still rubs me the wrong way when a self appointed keyboard metallurgist calls me an idiot in my video comments. I'll take a deep breath now.
@PaulShinn Since I imagine just about every running ‘A’ has had the engine rebuilt at some point, what was their objection to a detergent oil in it afterwards?
And apparently the starter of this thread doesn’t like the “conversation” all that much. He hasn’t been back since starting the thread 4 months ago.