heat and dirt and moisture in the oil are the problems, changing oil and filters tends to prevent problems, modern oils are far better than what we had in the past, but Id suggest no more than 5K miles between oil and filter changes with mineral base oils and changing the oil filter on synthetics at 5000-miles and changing the oil an filter at 10K. remember oil must reach about 215F to burn off moisture so don,t try to keep the oil temp lower than that all the time I generally try to keep engine oil temps in the 190f-215 range and don,t worry about oil temps reaching 250F for brief periods
adding a few magnets to the oil pan helps trap metallic dust and crud btw.
on synthetic oils, the advantage is slightly better film strength , better high heat lubrication,and a noticeably higher heat resistance to break down, most mineral base oils start to break down slowly at about 240F and bye 260F they start breaking down far faster, most synthetics easily operate up to 280F-290F without breaking down quickly
keep in mind modern oils are designed to trap and transport crud to the filter, but it takes a decent filter to make the system work as designed, (removing the crud from the oil flow)
http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html#fram-ph8a
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=120&p=150&hilit=magnet#p150
http://www.digitalcorvettes.com/forums/showthread.php?t=85963
quick story
I had, at the time, a MUNCIE M21 in one of my corvettes,(the 1968)
it worked ok but it always had a slight whine and shifts were a bit sluggish, ,after I had the car about a week, I mentioned that to a buddy who was a pro nascar mechanic at the time, he ask me about the lube,I was using,Id just filled the trans with the Chevy dealer recommended lube so I told him it was full and new,( I had no clue (back in 1971) synthetics were almost unheard of back then, ) he brought some over to the house amd we drained the old lube, replaced it with what he swore was what they used at his shop.......the difference was ASTOUNDING, the whine disappeared, the shifts smoothed out over the first few hours, I could hardly believe it was the same transmission. yes theres advantages, and yes Id recommend a good synthetic like MOBILE or AMSOIL
manual transmissions generally benefit from oil changes about every 60K
this thread might be useful
viewtopic.php?f=50&t=614&p=5180#p5180
Gear Oil 101: Which Lube is Right for Your Manual Transmission?
Posted by OnAllCylinders Staff on November 10, 2017 at 9:00 am
Selecting the right gear oil or transmission fluid is critical to the life and performance of your manual transmission. (Image/Tremec)
Similar to what we discussed in our Automatic Transmission Fluid 101post, selecting the right gear oil for your manual transmission isn’t as easy as it might seem.
There are dozens of different types of gear oils, each with its own special designation and use, so we created this handy primer (oil pun!) to help you make good decisions.
Keep in mind that most modern manual transmissions have gear oil service intervals well north of 50,000 miles, with many being “lifetime” oils.
Driving enthusiasts, however, change gear oil to deliver improved transmission performance—like smoother shifting or added durability in extreme conditions. If this sounds like you, keep reading.
Gear oil, AKA gear lube, is often used in your manual transmission’s gearbox, and you’ll commonly find it in older transfer and differential cases too. But gear lube isn’t the only choice for a manual transmission. In fact, many modern manual transmissions actually spec for automatic transmission fluid instead of a traditional gear oil. Regardless of what your manual transmission uses, the fluid or oil’s primary function is lubrication—preventing metal-to-metal contact between the meshing gears.
Gear oil is different from engine oil.
For starters, gear oil can come in much higher viscosity ratings. In other words, a 80w-90 gear oil is much “thicker” than a 5w-30 engine oil.
But viscosity is only part of the equation. Here’s why:
Manual transmissions are often made up of different metals. The gears can be made of a hardened steel, while the transmission’s synchronizers (AKA syncros) are often made of a softer metal, like brass.
What’s good for one metal may adversely affect the other—so companies had to develop formulations that offered the requisite lubrication, yet wouldn’t harm any of the transmission’s components.
This is also where GL ratings come into play.
The most common ones you’ll see are GL-4 and GL-5. Those ratings basically reflect the oil’s ability to function effectively given different driving conditions (read: pressure between meshing gear teeth). GL-4 oils are typically found in most daily driven cars. while GL-5 oils are often reserved for high-stress, high performance applications like trucks and high-powered cars.
Your owner’s manual will tell you exactly what GL rating your transmission requires.
Sometimes you’ll see a bottle labeled MT-1. It’s intended for non-synchronized transmissions, like those found in heavy-duty commercial trucks, and certain four-wheel drive transfer cases.
You can find the gear oil’s viscosity and GL rating on its label. (Image/Summit Racing)
What about transaxles?
Though the role of the gear oil is the same, there are extra factors at play in a transaxle. That’s because transaxles function as both an axle and transmission. You can read more about transaxles and how they differ from transmissions here.
For instance, you might find different oil recommendations depending on whether the transaxle has a built-in limited-slip differential (LSD). In other words, seemingly identical cars may require different oil, depending on the presence of an optional LSD.
So, what should I use, then?
We could dedicate a dozen posts to the answer, but since this is a 101, here’s the simplest solution: Check your vehicle owner’s manual.
It will spell out exactly what oil you should use, complete with viscosity and GL values specific to your vehicle.
Bottom line: To avoid transmission damage, you must consider several factors (including viscosity and formulation) when selecting your gear oil.
adding a few magnets to the oil pan helps trap metallic dust and crud btw.
on synthetic oils, the advantage is slightly better film strength , better high heat lubrication,and a noticeably higher heat resistance to break down, most mineral base oils start to break down slowly at about 240F and bye 260F they start breaking down far faster, most synthetics easily operate up to 280F-290F without breaking down quickly
keep in mind modern oils are designed to trap and transport crud to the filter, but it takes a decent filter to make the system work as designed, (removing the crud from the oil flow)
http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html#fram-ph8a
http://forum.grumpysperformance.com/viewtopic.php?f=54&t=120&p=150&hilit=magnet#p150
http://www.digitalcorvettes.com/forums/showthread.php?t=85963
quick story
I had, at the time, a MUNCIE M21 in one of my corvettes,(the 1968)
it worked ok but it always had a slight whine and shifts were a bit sluggish, ,after I had the car about a week, I mentioned that to a buddy who was a pro nascar mechanic at the time, he ask me about the lube,I was using,Id just filled the trans with the Chevy dealer recommended lube so I told him it was full and new,( I had no clue (back in 1971) synthetics were almost unheard of back then, ) he brought some over to the house amd we drained the old lube, replaced it with what he swore was what they used at his shop.......the difference was ASTOUNDING, the whine disappeared, the shifts smoothed out over the first few hours, I could hardly believe it was the same transmission. yes theres advantages, and yes Id recommend a good synthetic like MOBILE or AMSOIL
manual transmissions generally benefit from oil changes about every 60K
this thread might be useful
viewtopic.php?f=50&t=614&p=5180#p5180
Gear Oil 101: Which Lube is Right for Your Manual Transmission?
Posted by OnAllCylinders Staff on November 10, 2017 at 9:00 am
Selecting the right gear oil or transmission fluid is critical to the life and performance of your manual transmission. (Image/Tremec)
Similar to what we discussed in our Automatic Transmission Fluid 101post, selecting the right gear oil for your manual transmission isn’t as easy as it might seem.
There are dozens of different types of gear oils, each with its own special designation and use, so we created this handy primer (oil pun!) to help you make good decisions.
Keep in mind that most modern manual transmissions have gear oil service intervals well north of 50,000 miles, with many being “lifetime” oils.
Driving enthusiasts, however, change gear oil to deliver improved transmission performance—like smoother shifting or added durability in extreme conditions. If this sounds like you, keep reading.
Gear oil, AKA gear lube, is often used in your manual transmission’s gearbox, and you’ll commonly find it in older transfer and differential cases too. But gear lube isn’t the only choice for a manual transmission. In fact, many modern manual transmissions actually spec for automatic transmission fluid instead of a traditional gear oil. Regardless of what your manual transmission uses, the fluid or oil’s primary function is lubrication—preventing metal-to-metal contact between the meshing gears.
Gear oil is different from engine oil.
For starters, gear oil can come in much higher viscosity ratings. In other words, a 80w-90 gear oil is much “thicker” than a 5w-30 engine oil.
But viscosity is only part of the equation. Here’s why:
Manual transmissions are often made up of different metals. The gears can be made of a hardened steel, while the transmission’s synchronizers (AKA syncros) are often made of a softer metal, like brass.
What’s good for one metal may adversely affect the other—so companies had to develop formulations that offered the requisite lubrication, yet wouldn’t harm any of the transmission’s components.
This is also where GL ratings come into play.
The most common ones you’ll see are GL-4 and GL-5. Those ratings basically reflect the oil’s ability to function effectively given different driving conditions (read: pressure between meshing gear teeth). GL-4 oils are typically found in most daily driven cars. while GL-5 oils are often reserved for high-stress, high performance applications like trucks and high-powered cars.
Your owner’s manual will tell you exactly what GL rating your transmission requires.
Sometimes you’ll see a bottle labeled MT-1. It’s intended for non-synchronized transmissions, like those found in heavy-duty commercial trucks, and certain four-wheel drive transfer cases.
You can find the gear oil’s viscosity and GL rating on its label. (Image/Summit Racing)
What about transaxles?
Though the role of the gear oil is the same, there are extra factors at play in a transaxle. That’s because transaxles function as both an axle and transmission. You can read more about transaxles and how they differ from transmissions here.
For instance, you might find different oil recommendations depending on whether the transaxle has a built-in limited-slip differential (LSD). In other words, seemingly identical cars may require different oil, depending on the presence of an optional LSD.
So, what should I use, then?
We could dedicate a dozen posts to the answer, but since this is a 101, here’s the simplest solution: Check your vehicle owner’s manual.
It will spell out exactly what oil you should use, complete with viscosity and GL values specific to your vehicle.
Bottom line: To avoid transmission damage, you must consider several factors (including viscosity and formulation) when selecting your gear oil.
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