I'm not gonna argue, 'cause I don't know for fact. But I will throw this out there for your consideration. Why would virtually all of the new car MFG's use synthetic oil and then warranty their drivetrains for 100k miles if it afforded less protection that (the much cheaper) dino oils?
Agreed. Once Chrysler started messing with synthetic diff fluid our failures went through the roof. They layed all the blame on Dana.
I think how the gears are made has a lot to do with whether synthetic is required or not. Some of the limited slip manufacturers have requirements to use regular gear lube because of it's compatibility with the friction modifiers, but lockers don't use friction modifiers. Ford had issues with the 75W-90 HP synthetic gear oils but the repair was to drain it and refill with 75W-140 synthetic. I have been running 75w-140 in my 8" with a Detroit Tru-Trac for 5 years+ and I have no leaks. Some gear manufacturers do have their requirements and synthetic oils may inhibit the break in process so I would use what they recommend or what is already in it if it's not causing a problem. I wouldn't just change to synthetic for the sake of doing so.
i belive that they do it to increase there fleet fuel economy rating. i also belive the high cost of synthetic oil is hype and doesnt really cost significantly more to the manifactures. its ignorant to belive that the car manifactures are building the cars a best as the can with the best products.
I would definitely agree with that statement 2 opposing forces are at work in the car manufacturing scheme: one side is the engineers presented with the job of making a very good product to sell and on the other side, accountants who's job it is to get rid of all the "unecessary costs" to reduce the price to something the buying public will purchase. The OEM's will build it the best they can as cheap as possible at a price as high as the market will bear. Such is the nature of free markets.
I run 80w90 conventional in my mav's diff, haven't had any issues at all... Though there are a couple guys that come into the shop, and prefer to use the 75w140 synthetic (it's a GL5) Synthetic doens't CAUSE leaks though, but due to the uniform nature of the molecules in the oil, there is less friction between them (or fluid shear) that will allow it to leak out faster. ON a side note, one of the TSB's we have on the older trucks, specify not to use a standard 75w140, but to use Redline 75w90... as the 75-140 does not absorb water/humidity, wich could lead to internal corrosion. The redline 75w90 does absorb the moisture. Aside from that, other food for thought, a lot of guys i've talked to that have leaks and place blames, are more common than not, not using a sealant ont he new cover gasket, or even worse... using a sealer and not letting it set up (when it gets tacky) and squirting it on and throwing the plate on the differential. If you get excessive oozing of the sealant, the possibility for leaks is a lot higher. Sometimes a bit of patience is worth the pain later
tell me if im wrong but wouldn't they do that also for the ability to sell the product overall? like a way to set the hook on the customer is to have all these plus
regarding the sealant text from cowboiup1979. yeah as along as the rtv or what ever is allowed to set up for awhile it makes great gaskets. i use it for my intakes instead of those silly cork ones that go between the heads and one rear end cover in college autotech. i just let my rtv set up for atleast 10mins 20mins if i have the time to wait
I've made good use of RTV sealant, on carb to intake gasket, the intake to head gaskets, and a couple diff covers, the high temp stuff works great, even on water necks, and ONCE, used it to seal the dreaded window washer line on a 2000 ford taurus, vacuum line + Sealant + Clamps = better than new we see tons of those come in with broken washer lines... that old platic gets soo damned brittle.
wow good idea man! i could see that working well if done right haha. also rtv as a carb gasket is good thinking.ha
