I stopped at one of those mobil express shops last week ( I was at goodyear next door having my alignment done) and inquired about replacing the gear oil in my manual trans with synthetic, the guy told me to check with a tranny shop because he said something about the synthetic not being compatible with the seals in the tranny?? Anyone know anything about this?
Doubtful it is going to cause any problems with the seals themselves other than possibly sneaking out past them. LOL.
when I bought my car, I changed both axles and both axle seals and at that time I installed Castol Hypoy C gear oil. My car is driven highway daily. It doesn't leak a drop, is nice and quiet, and shifts great. I would use this oil again in a minute. (it's not synthetic) . Not saying it is the best out there, but my tranny seems to like it.
astreamk1: "I changed both axles and both axle seals and at that time I installed Castol Hypoy C gear oil. My car is driven highway daily. It doesn't leak a drop, is nice and quiet, and shifts great. I would use this oil again in a minute. (it's not synthetic) . Not saying it is the best out there, but my tranny seems to like it."
So how long has this stuff been in there?
Some trannies are more picky than others ... and any problems with synchros, etc ... may take some time to become apparent.
the beggest difference between synthetic and conventional is that syn. is slicker and will leak out through worn seals but as for fuging then up no and it should have no effect on your internals so I would say go for it.
Some trannies are more picky than others ... and any problems with synchros, etc ... may take some time to become apparent.[/quote]
It has been in the car about a year and a half. I wouldn't expect it to have any problems. Most of these B12's have never had their gearbox oil changed and are still running strong. The Castrol Hypoc C is nothing special, just a decent quality gear oil. putting synthetic in one of these cars at this point in their life is probably not going to make much difference one way or another at this point.
If your tranny is on it's way to a fifth gear pop out scenario, it is most likely going to happen anyways. doubtful any oil is gonna save you.
"Most of these B12's have never had their gearbox oil changed and are still running strong."
Yeah, lots of manual trannies get ZERO maintenance but somehow, most of them seem to more-or-less survive.
"The Castrol Hypoid C is nothing special, just a decent quality gear oil. putting synthetic in one of these cars at this point in their life is probably not going to make much difference one way or another at this point."
Probably not. The synthetic oils are mostly for shift feel ... especially in the cold. But then again, some designs are more sensitive to this than others.
"If your tranny is on it's way to a fifth gear pop out scenario, it is most likely going to happen anyways. Doubtful any oil is gonna save you."
Yeah, that depends on what's wearing out that causes that to happen ... but you're probably right.
synthetics are better because they handle heat better and resist break down but yeah at this point there is no real need to pay the extra for it and as for M/T's surviving 0 maintence that is cause 90w is some nasty ass stuff that only gets nastier with age but never seems to break down and you don't get the polutants in a tranny you do in an engine.
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