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Two questions: 1. what are some recommended tools/pumps for removing fluids from the diff. and trans. and 2. is it wise to use synthetics and which would be appropriate for the trans and a posi. diff. ? Is any additive needed? Thanks.
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Re: 63 diff fluid chg
I use a Mity Vac to remove old fluid with good results. -
Re: 63 diff fluid chg
I use a Mity Vac to remove old fluid with good results.Comment
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Re: 63 diff fluid chg
inexpensive suction pump(NAPA etc) will get some but not all the old gear oil. i wouldn't use mobile synthetic gear oil unless you've just rebuilt the tranny and differential, in which case you won't need the suction pump. your c-3 has made it this many decades with standard gear oil and synthetic won't give any noticble improvements in the average lifetime of the vette. only place i use synthetic gear oil(Mobile) is the differential of my full chevy pickup i use to pull the enclosed trailer at Interstate speeds.and i change it evfery 25K miles as i've had problems with other pickups in the past that were posi equipped and asked to pull 10K lbs at or above Interstate speeds. mikeComment
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Re: 63 diff fluid chg
inexpensive suction pump(NAPA etc) will get some but not all the old gear oil. i wouldn't use mobile synthetic gear oil unless you've just rebuilt the tranny and differential, in which case you won't need the suction pump. your c-3 has made it this many decades with standard gear oil and synthetic won't give any noticble improvements in the average lifetime of the vette. only place i use synthetic gear oil(Mobile) is the differential of my full chevy pickup i use to pull the enclosed trailer at Interstate speeds.and i change it evfery 25K miles as i've had problems with other pickups in the past that were posi equipped and asked to pull 10K lbs at or above Interstate speeds. mikeComment
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Re: 63 diff fluid chg
There's no legal or technical definition of "synthetic" as it applies to automotive lubricants. Rather, base oils are differentiated by their viscosity index, so some 75W-90 gear oils are labeled "synthetic", but unless you are driving in subzero weather, they offer little benefit. I don't think too many of us drive vintage Corvettes in weather equivalent to the Alaska North Slope oil fields!
In any case, the specified OE lubricant for vintage manual transmissions is MIL-L-2105D, which has been cancelled and superseded by API GL-5, and the same applies to axles with the exception that Positraction axles require the friction modifier additive.
GL-5s blended from common base stocks carry an 80W-90 SAE viscosity rating and are more than adequate for the mild temperatures that most vintage Corvettes see.
Do not be sucked in by the "GL-5 corrodes synchronizers" hype that you see on the internet. Have you ever seen or heard of and old four-speed that lived on GL-5 that had corroded synchonizers? I haven't. Wear, yes, Corrosion, no.
Some want to use GL-4 in vintage four speeds. I don't agree. Use GL-5, which is the modern version of MIL-L-2105D that GM recommended.
Selection of gear oils is the same as motor oils. Brand name is unimportant! What IS important is the API service category rating and SAE viscosity rating.
DukeComment
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Re: 63 diff fluid chg
There's no legal or technical definition of "synthetic" as it applies to automotive lubricants. Rather, base oils are differentiated by their viscosity index, so some 75W-90 gear oils are labeled "synthetic", but unless you are driving in subzero weather, they offer little benefit. I don't think too many of us drive vintage Corvettes in weather equivalent to the Alaska North Slope oil fields!
In any case, the specified OE lubricant for vintage manual transmissions is MIL-L-2105D, which has been cancelled and superseded by API GL-5, and the same applies to axles with the exception that Positraction axles require the friction modifier additive.
GL-5s blended from common base stocks carry an 80W-90 SAE viscosity rating and are more than adequate for the mild temperatures that most vintage Corvettes see.
Do not be sucked in by the "GL-5 corrodes synchronizers" hype that you see on the internet. Have you ever seen or heard of and old four-speed that lived on GL-5 that had corroded synchonizers? I haven't. Wear, yes, Corrosion, no.
Some want to use GL-4 in vintage four speeds. I don't agree. Use GL-5, which is the modern version of MIL-L-2105D that GM recommended.
Selection of gear oils is the same as motor oils. Brand name is unimportant! What IS important is the API service category rating and SAE viscosity rating.
DukeComment
Comment