Manual transmission issues
12-04-2012, 06:18 PM
#21
sorry not sure what I was thinking. Mixing up both manual and auto. Thats is what happens when you spend too much time on G35 driver.
Disregard what I said about 3 swaps that pertains to auto
Manual
Oil capacity (US qt, Imp qt) Approx. 2.9 (3-1/8, 2-1/2)
Auto
Fluid capacity: 10.3 (10-7/8 US qt, 9-1/8 lmp qt)
Disregard what I said about 3 swaps that pertains to auto
Manual
Oil capacity (US qt, Imp qt) Approx. 2.9 (3-1/8, 2-1/2)
Auto
Fluid capacity: 10.3 (10-7/8 US qt, 9-1/8 lmp qt)
12-04-2012, 06:50 PM
#22
This is true, but a lubricant labeled as meeting both the GL-4 and GL-5 specifications would not meet the specs for a GL-4 transmission oil. The GL-5 specification was designed to specify an oil whose chemistry is better suited to handling the severe sliding and loading conditions imposed by hypoid gear mechanisms than older GL-4 lubricants. So, by design, a GL-5 gear oil can also be labeled as meeting the GL-4 specification for gear oils, in much the same way that a 93 octane fuel will 'meet' the lower anti-knock specifications of a 91 octane rated fuel. However, this does not mean that a GL-5 gear oil is better, or can be substituted, for a GL-4 requirement.
The extreme pressure (EP) additives used to meet the GL-5 oil standard must chemically alter (corrode) the gear surfaces in order to establish a film strong enough to withstand the high pressures and not be removed by heat and friction. Most EP additives are composed of sulfur, phosphorous and chlorine compounds for this reason. These compounds can corrode the surface of, and then be removed by friction from, softer metals such as brass or copper. Hence, the old scare that GL-5 gear oils will destroy brass synchros in a transmission. Even an oil claiming to meet both the GL-4 and GL-5 standards. This is really not a huge issue for most gear oils though, since modern gear oils typically contain buffers to help protect softer metals from corrosion. The real problem is that the EP additives also reduce the sliding friction across the reacted surfaces. This is normally a good thing, but the synchronizers in a manual transmission require friction to operate. When you use your shift lever to slide a synchronizer ring (spinning at the same speed as your input shaft) into a selected drive gear (spinning at a different speed), friction is what transfers the energy from the synchronizer to the selected gear and brings it up (or down) to speed. Once the rotating speed fo the gear matches the synchronizer, then the locking ring on the synchro can slide over and lock into the drive gear, completed the shift. How long this process takes is directly impacted by the rate of frictional energy transfer. Oils which meet the GL-5 specification will slow this energy transfer down because they reduce friction across the reacted gear surfaces.
Manual transmissions that spec a GL-4 oil are specifying a gear oil with lower amounts of EP additives for this very reason. Thus, a GL-4/GL-5 gear oil does not meet the lubricant specification, because GL-5 is not 'backwards compatible' with GL-4. For proper operation, the transmission oil needs to only meet the GL-4 spec, and NOT the GL-5 specification.
Will
The extreme pressure (EP) additives used to meet the GL-5 oil standard must chemically alter (corrode) the gear surfaces in order to establish a film strong enough to withstand the high pressures and not be removed by heat and friction. Most EP additives are composed of sulfur, phosphorous and chlorine compounds for this reason. These compounds can corrode the surface of, and then be removed by friction from, softer metals such as brass or copper. Hence, the old scare that GL-5 gear oils will destroy brass synchros in a transmission. Even an oil claiming to meet both the GL-4 and GL-5 standards. This is really not a huge issue for most gear oils though, since modern gear oils typically contain buffers to help protect softer metals from corrosion. The real problem is that the EP additives also reduce the sliding friction across the reacted surfaces. This is normally a good thing, but the synchronizers in a manual transmission require friction to operate. When you use your shift lever to slide a synchronizer ring (spinning at the same speed as your input shaft) into a selected drive gear (spinning at a different speed), friction is what transfers the energy from the synchronizer to the selected gear and brings it up (or down) to speed. Once the rotating speed fo the gear matches the synchronizer, then the locking ring on the synchro can slide over and lock into the drive gear, completed the shift. How long this process takes is directly impacted by the rate of frictional energy transfer. Oils which meet the GL-5 specification will slow this energy transfer down because they reduce friction across the reacted gear surfaces.
Manual transmissions that spec a GL-4 oil are specifying a gear oil with lower amounts of EP additives for this very reason. Thus, a GL-4/GL-5 gear oil does not meet the lubricant specification, because GL-5 is not 'backwards compatible' with GL-4. For proper operation, the transmission oil needs to only meet the GL-4 spec, and NOT the GL-5 specification.
Will
12-04-2012, 06:53 PM
#23
So I replaced the fluid with synchromesh today and Its 1000 times better so better. I'm hoping it'll get a little bit smoother after the fluid gets hot a couple times and coats everything again. I guess I need to drive another 350z or g35 around here and see how there's feels before doing anything else.
Will
12-05-2012, 06:09 AM
#24
Registered User
Join Date: Aug 2012
Location: Atlanta
Posts: 176
Likes: 0
Received 0 Likes
on
0 Posts
This is true, but a lubricant labeled as meeting both the GL-4 and GL-5 specifications would not meet the specs for a GL-4 transmission oil. The GL-5 specification was designed to specify an oil whose chemistry is better suited to handling the severe sliding and loading conditions imposed by hypoid gear mechanisms than older GL-4 lubricants. So, by design, a GL-5 gear oil can also be labeled as meeting the GL-4 specification for gear oils, in much the same way that a 93 octane fuel will 'meet' the lower anti-knock specifications of a 91 octane rated fuel. However, this does not mean that a GL-5 gear oil is better, or can be substituted, for a GL-4 requirement.
The extreme pressure (EP) additives used to meet the GL-5 oil standard must chemically alter (corrode) the gear surfaces in order to establish a film strong enough to withstand the high pressures and not be removed by heat and friction. Most EP additives are composed of sulfur, phosphorous and chlorine compounds for this reason. These compounds can corrode the surface of, and then be removed by friction from, softer metals such as brass or copper. Hence, the old scare that GL-5 gear oils will destroy brass synchros in a transmission. Even an oil claiming to meet both the GL-4 and GL-5 standards. This is really not a huge issue for most gear oils though, since modern gear oils typically contain buffers to help protect softer metals from corrosion. The real problem is that the EP additives also reduce the sliding friction across the reacted surfaces. This is normally a good thing, but the synchronizers in a manual transmission require friction to operate. When you use your shift lever to slide a synchronizer ring (spinning at the same speed as your input shaft) into a selected drive gear (spinning at a different speed), friction is what transfers the energy from the synchronizer to the selected gear and brings it up (or down) to speed. Once the rotating speed fo the gear matches the synchronizer, then the locking ring on the synchro can slide over and lock into the drive gear, completed the shift. How long this process takes is directly impacted by the rate of frictional energy transfer. Oils which meet the GL-5 specification will slow this energy transfer down because they reduce friction across the reacted gear surfaces.
Manual transmissions that spec a GL-4 oil are specifying a gear oil with lower amounts of EP additives for this very reason. Thus, a GL-4/GL-5 gear oil does not meet the lubricant specification, because GL-5 is not 'backwards compatible' with GL-4. For proper operation, the transmission oil needs to only meet the GL-4 spec, and NOT the GL-5 specification.
Will
The extreme pressure (EP) additives used to meet the GL-5 oil standard must chemically alter (corrode) the gear surfaces in order to establish a film strong enough to withstand the high pressures and not be removed by heat and friction. Most EP additives are composed of sulfur, phosphorous and chlorine compounds for this reason. These compounds can corrode the surface of, and then be removed by friction from, softer metals such as brass or copper. Hence, the old scare that GL-5 gear oils will destroy brass synchros in a transmission. Even an oil claiming to meet both the GL-4 and GL-5 standards. This is really not a huge issue for most gear oils though, since modern gear oils typically contain buffers to help protect softer metals from corrosion. The real problem is that the EP additives also reduce the sliding friction across the reacted surfaces. This is normally a good thing, but the synchronizers in a manual transmission require friction to operate. When you use your shift lever to slide a synchronizer ring (spinning at the same speed as your input shaft) into a selected drive gear (spinning at a different speed), friction is what transfers the energy from the synchronizer to the selected gear and brings it up (or down) to speed. Once the rotating speed fo the gear matches the synchronizer, then the locking ring on the synchro can slide over and lock into the drive gear, completed the shift. How long this process takes is directly impacted by the rate of frictional energy transfer. Oils which meet the GL-5 specification will slow this energy transfer down because they reduce friction across the reacted gear surfaces.
Manual transmissions that spec a GL-4 oil are specifying a gear oil with lower amounts of EP additives for this very reason. Thus, a GL-4/GL-5 gear oil does not meet the lubricant specification, because GL-5 is not 'backwards compatible' with GL-4. For proper operation, the transmission oil needs to only meet the GL-4 spec, and NOT the GL-5 specification.
Will
Last edited by SlowNFurious; 12-05-2012 at 06:21 AM.
Thread
Thread Starter
Forum
Replies
Last Post
Colombo
Forced Induction
35
11-09-2020 10:27 AM
