I couldn't resist jumping in on this one.
I try to use what ever the manufacturer recommends in my truck. After all they have had engineers that are much better than I am at figuring out all the pros and cons of what lube to use. I would not like to second guess the "experts". But I am willing to change if there is good reason.
Synthetics are excellent in many situations but the jury is still out on those. Does the cost out way the benefits?
One big reason to use the recommended lube is the contact between gears is cushioned by the lube. I know we are talking about the transmissin, but how long will your crankshaft last without this type of cushioning? Couldn't this eventually have the same effect on your transmission?
Another aspect to consider is that hypiod gear oil is formulated to prevent air from being whipped into the lube causing foaming. This can lead to early failure of parts that come into contact with each other.
The climate up here does make it hard for the lube to get moving, so a little gentle warm up doesn't hurt.
Always interested in what others have to say. Has anyone used a synthetic for a long period of time and could maybe enlighten the group?
