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Bruce Samba Member
Joined: May 16, 2003 Posts: 17273 Location: Left coast, Canada
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Posted: Sat Jan 03, 2015 3:28 am Post subject: |
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RichardLW wrote: |
I don't ignore steel wear. There is very little steel wear if the transmission is designed for GL-4. |
What a fantasy!
Early last year my buddy had 3 cars in a row where the R&Ps went south. When opened, they were torn up from metal to metal contact.
The going rate for a German 3.88 is now $300 each. New German 3.88s don't exist, so it's $250 for a China 3.88. Still think it's important to save $40 worth of synchros?
Here's another: German 5mm 1-2 sliders. If you can find NOS, they are north of $200. The groove for the fork wears big. The engagement teeth's flanks wear, the reverse teeth wear. That's 4 different places where they wear out. I know of one guy who has developed a machining procedure to make one good slider from two bad ones.
Reverse idler gear. The late reverse idler gear takes a beating. Drivers that like to give big throttle in reverse are the ones that cause the reverse teeth to start to roll over. The problem is that the contact ratio is so small. In rare cases, you get lucky and it's good. Otherwise, every rebuild needs a new one. Steel on steel contact.
Four forward gears. The actual helical gear teeth stand up well. It's the engagement teeth that the slider couples with that wear badly. Here's a 4th gear:
The rounded tops don't have much affect on the way the gearbox shifts, so they're not much concern. It is the sides where the slider drives the gear that is very important. Look at the right sides of the teeth on the left side of the pic. You can clearly see an imprint from the contact of the slider.
Notice how the sides of the teeth are not parallel? This back-cut is so that the torque of the engine will help pull the slider into engagement, ie. to prevent popping out of gear. Due to severe metal to metal contact, eventually this back-cut gets worn away until the flank is parallel to the axis of the gear. That's when the slider will pop out of engagement. There is a fix for this, but it only works one time. Then you have to throw the gear away. If you want to use the stronger 9 tooth 3.78 first gear, the only source is good used. Until people using GL-4 destroy them all.
GL-5's higher extreme pressure capability helps reduce all of this type of wear. By using GL-4, you are purposely accelerating steel on steel wear. _________________
overheard at the portland Swap Meet... wrote: |
..... a steering wheel made from a mastadon tusk..... |
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RichardLW Samba Member
Joined: December 28, 2014 Posts: 20 Location: Santa Cruz, Bolivia
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RichardLW Samba Member
Joined: December 28, 2014 Posts: 20 Location: Santa Cruz, Bolivia
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Posted: Sat Jan 03, 2015 5:52 am Post subject: |
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You bring up, however indirectly, several interesting points. That is why we gather people from different sectors and professions to determine root cause failure. Each adds his point of view as to the cause. it is easy to place the blame on one item, and typically the first blame is placed on the oil.
Pictures help, but personal inspection by all is always best. Everyone gets better informed of the reasons for the other’s opinions when you have the tribologist with the factory engineer, the mechanic, driver, etc. present.
Shift forks fail for various reasons:
— Driving with one hand on the shifter (lets rule that out, as that is a rookie mistake)
— Poorly aligned shifter (we can probably rule this out, as we are talking about people who understand more than the average backyard mechanic)
— High dirt contamination in the oil. We need an oil analysis to determine that.
— High water contamination in the oil. Oil analysis is great, but it can be seen in the field with a zippo and part of a beer can.
— High oil level: Oil above the mid-point of the gears generally creates too much foam. Foam does not lubricate or form a film.
— Low oil level (obvious)
— Oxidized oil (oil operating over 70ºC oxidizes rapidly, forming gums and acids. It may still look like oil, but is not). The best solution to reduce oxidation is synthetic oil.
— Poor oil quality (lack of film strength or lack of additives)
— Wrong oil viscosity (too thin to stay put, too thick to get splashed all over).
— Too many additives. I have never measured the force required to shift with different oils in different temperatures, the force required to displace the sulfur/phosphorous coating on the synchronizers is considerably more with GL-5 than it is with GL-4. You have to press hard enough to peel off a micron or two of brass. All the time you are pressing, you are wearing the shift fork, perhaps more than the synchronizers. This pressure also adds heat to the synchronizer rings, fork, and oil. The heat also binds the sulfur/phos coating harder onto the parts. So with GL-4, the synchros act faster and easier, requiring much less pressure on the forks.
I want to come back to contamination, as I see it weekly, and have been involved with the investigation of various failures where people wanted their transmissions replaced under warranty and I was called in to investigate. The majority of transmissions or differentials are not designed for anything other than asphalt roads in “normal” environments, and designed to get you through the warranty period, little more. The respirators let out the hot air as the oil and air expand (oil at .7% per 10ºC and air at about 3% per 10ºC). As the parts cool at night or whenever, or when you drive into water for instant cooling, the dirty, moist air (or water) is drawn in. In my database I probably have 500 or so examples gear oil contaminated by dirt and at least 100 with water over 1% (up to 25% in one case). Some people close these off, thinking it will avoid the ingress, but that makes it worse as they then breath through the axle or driveshaft seals. The solution here is a tube, as equipped on some 4x4’s up to some place where water can’t get, ideally with a filter on the end, although the rubber tube will attract most of the dirt particles if it is long enough. _________________ Restoration in Bolivia
Richard's Corvair
Selection of the right transmission oil for the corvair
How to polish and restore stainless and aluminum trim |
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Quokka42 Samba Member
Joined: December 02, 2010 Posts: 3117 Location: Melbourne, Australia
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Posted: Sat Jan 03, 2015 6:20 am Post subject: |
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You have to understand Bruce makes a living out of building transmissions and has been very vocal in his support for GL-5. Two problems he will have if he admits that they are not always suitable - he may be held liable for failures due to his incorrect advice, and less failures mean less business. OK, the latter is a bit cynical, but he is vehement and even abusive on this topic...
I'm not so convinced about your belief that all oils with a GL-5 spec are bad. I have a friend, though I have lost contact with him, who is a metallurgist with a major oil company and assures me there are additives which can be used which overcome the sulphur problem and allow oils to be dual-specced GL-4 and GL-5, especially with synthetic oils. I know oil companies are loathe to release details of their "secret formulae" and are not above using marketing to replace science, but it does seem the science is there...
I think I'll give the Castrol Syntrax a go - I don't have access to the analysis, but time will tell.
BTW, Bruce isn't completely wrong - while I have seen 200k miles + on stock trannies running VW-recommended lube, in racing we were willing to sacrifice synchros long ago... I'm out of the scene but believe synthetics are all the go now. _________________ There has only ever been one man who was perfect, and they nailed Him to a cross. |
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RichardLW Samba Member
Joined: December 28, 2014 Posts: 20 Location: Santa Cruz, Bolivia
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Posted: Sat Jan 03, 2015 6:43 am Post subject: |
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Quote: |
I have a friend, though I have lost contact with him, who is a metallurgist with a major oil company and assures me there are additives which can be used which overcome the sulphur problem and allow oils to be dual-specced GL-4 and GL-5, especially with synthetic oils. I know oil companies are loathe to release details of their "secret formulae" and are not above using marketing to replace science, but it does seem the science is there... |
All GL-5 oils can be double-spec'd backwards to GL-4. Yes, there are a few exotic formulas of GL-4 that would probably pass GL-5, personally I suspect that Nissan's 75W-85 overbased calcuim sulfonate that we are working on duplicating would probably meet GL-5, but they are careful not to confuse the customers, always calling it a GL-4. It is a very expensive and exotic synthetic formula.
These days one has to be prepared to say: "What I recommended years ago was the best thing at the time. Better things are available today, so recommendations change." Volvo used to insist on GL-4 SAE 80W-90 in many of their transmissions, then switched their manuals to SAE 50 engine oil or SAE 50 CAT spec TO-4 for those same transmissions.
Everyone thought SM engine oils would solve catalytic converter problems, but no one realized it was the evaporation of certain ZDDP compounds that caused the problem in some oils. SN was launched that included an evaporation test for the phosphorous, and SM bit the dust.
And I understand racing. You throw out the rule books and go with what you need for the race. We use 5W-50 oils in engines designed for street use with 5W-30, but we know they will be running at 120ºC, so during the race they will be at the viscosity of a 5W-30 at 100ºC. _________________ Restoration in Bolivia
Richard's Corvair
Selection of the right transmission oil for the corvair
How to polish and restore stainless and aluminum trim |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Sat Jan 03, 2015 6:48 am Post subject: |
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Quokka42 wrote: |
You have to understand Bruce makes a living out of building transmissions and has been very vocal in his support for GL-5. |
Sounds like you're saying that Bruce is intentionally telling people to use a product that will cause transmissions to wear faster so he can profit by rebuilding them.
Bruce rebuilt my ZF LSD 3 years ago in exchange for a distributor rebuild and has yet sent it to me. If he was a "money grubber" he would of asked for cash up front. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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miniman82 Samba Swamp Donkey
Joined: March 22, 2005 Posts: 9515 Location: Southern Maryland
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Posted: Sat Jan 03, 2015 7:53 am Post subject: |
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Quokka42 wrote: |
You have to understand Bruce makes a living out of building transmissions and has been very vocal in his support for GL-5. |
I see...
What do I stand to gain? If my transmission fails, I have to get another one or have Bruce rebuild it... So what's my excuse, oil oracle? _________________ Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747
Glenn wrote: |
satterley_sr wrote: |
I just wanted to bitch but I'm getting no sympathy. |
Welcome to the Samba. |
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gears Samba Member
Joined: October 28, 2002 Posts: 4391 Location: Tamarack, Bend, Kailua
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Posted: Sat Jan 03, 2015 10:03 pm Post subject: |
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RichardLW wrote: |
There is a huge difference between GL-4 and GL-5 when it comes to transmissions. GL-5 has twice the sulfur/phos additive. It grabs the synchronizers so well that when you shift instead of sliding off (as it would steel gears), it peels off a micron or two of brass. A micron may not seem like much, but 80 of them make the width of a human hair. It adds up.
Forget the discussions about corrosion caused by the sulfur. It has been buffered in all brands for 20 to 30 years. Dead argument. We are worried about it peeling the brass off the teeth. I have lots of worn synchronizers to show that. Those who say their GL-5 will not corrode brass are right. but it will peel it.
I am in the process of documenting the reduction of copper wear (from the brass) in manual transmissions by 700% through a switch from GL-5 to GL-4. I've got more than 60,000 miles documented so far in MB interstate buses with brass synchronizers.
The simple question most people still ask (yes, I get an email or two a day) is why isn't a GL-4/GL-5 a GL-4 for transmissions. And the simple answer is the GL categories only look at wear protection. They do not look at synchronizer protection.
Someone talked about the need to use higher GL protection to protect the scarce parts. Bad argument. The GL-5 will damage brass, and not offer more protection to the gears than you need, unless you have mated your VW transmission to a 300 hp engine.
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In five separate paragraphs, you've referred to the damage to brass synchronizers caused by GL-5 .. specifically, you are “worried about it peeling the brass off the teeth.” and “(you) have lots of worn synchronizers to show that.”
I'm curious as to the vintage of the MB interstate bus TRANSMISSIONS which you refer to .. from what year bus have you photographed the brass synchronizer ?
Since you're documenting this damage caused by GL-5 gear lube(s), could you please show us some clear photos of synchro rings exhibiting the worst case damage you're referring to, alongside “average damage”? TIA for showing us those photos (please host on Samba so we can see them).
Regarding the statement that “GL-5 ... will not offer more protection to the gears than you need, unless you have mated your VW transmission to a 300 hp engine” ..
A) Are you referring specifically to the R&P, found in any Porsche or VW TRANSAXLE, since these are the “gears” that would most benefit from GL-5? (I can understand how someone might call a VW 6.17 Syncro R&P “scarce”, SINCE THEY ARE NO LONGER AVAILABLE).
B) Are you aware that 300 hp is about what a souped up 911 Porsche NA engine delivers? (For further reference, a Porsche GT3R track car has about 340 hp, and wears out 3rd & 4th gearsets within 40 road-racing hours.)
Given that ..
1) A Subaru H6 conversion is equivalent in horsepower to a Porsche 3.2 (roughly 240 hp) ..
2) Porsche transaxles components are far larger than their VW counterparts (see pinion photo below, VW 6.17, VW 4.86, Porsche G50 3.44), thus “less in need of added protection”, and yet Porsche specifies GL-5 for even their street cars ..
.. can you understand how we would regard your 300 hp figure as ridiculous ? .. as is your statement that GL-5 can't offer added protection for our FAR smaller VW R&Ps ?
All of this aside, given that VW has been moly coating their synchronizers since the late-70's (NO BARE BRASS), and that earlier VW transaxles (which DO use bare brass synchro rings) rarely run above 150*F, how relevant is your soapboxing about brass synchronizer erosion?
RichardLW wrote: |
Those of us who sell oils would MUCH rather stock one transmission oil than 12 different ones. |
OK .. beginning to understand now .. _________________ aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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Bruce Samba Member
Joined: May 16, 2003 Posts: 17273 Location: Left coast, Canada
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Posted: Sun Jan 04, 2015 1:49 am Post subject: |
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Quokka42 wrote: |
You have to understand Bruce makes a living out of building transmissions and ... |
Wrong.
Local VW people come to me for rebuilds because they don't want a gearbox made from a worn out California core.
Quokka42 wrote: |
and less failures mean less business. ... |
suits me fine. My attitude is the same as your dentist. I do my best to make you never return.
Quokka42 wrote: |
.... he is vehement and even abusive on this topic... |
Ironic, coming from you. _________________
overheard at the portland Swap Meet... wrote: |
..... a steering wheel made from a mastadon tusk..... |
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Quokka42 Samba Member
Joined: December 02, 2010 Posts: 3117 Location: Melbourne, Australia
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Posted: Sun Jan 04, 2015 3:09 am Post subject: |
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And when have I ever been abusive? Whereas anyone can go back a few pages in this thread and observe your comments. _________________ There has only ever been one man who was perfect, and they nailed Him to a cross. |
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RichardLW Samba Member
Joined: December 28, 2014 Posts: 20 Location: Santa Cruz, Bolivia
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Posted: Sun Jan 04, 2015 5:43 am Post subject: |
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I don't have as many pictures as I'd like, but here are some that I have identified and can easily find on my hard drive. Many of my collection are viscosity related transmission failures.
Also attaching the analysis sheet for one of the MB buses I'm working with. On that you can see where copper wear is down significantly, even though dirt contamination is up. The center column has little meaning, as it still has to peel & rinse old oil.
Obviously in transmissions where brass is not used, the problem of peeling brass is not a problem.
As I mentioned in racing, you throw out the books
I end up spending a great deal of time with dealers and manufacturers solving problems that could have been avoided, but customers and distributors of some brands insist that since the labels say GL-4/GL-5, they can use it. The distributor for one brand ended up paying for a transmission rebuild and stopped selling GL-5 for transmissions until his stock of GL-4 came in, sending his customers to me in the mean time.
_________________ Restoration in Bolivia
Richard's Corvair
Selection of the right transmission oil for the corvair
How to polish and restore stainless and aluminum trim |
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gears Samba Member
Joined: October 28, 2002 Posts: 4391 Location: Tamarack, Bend, Kailua
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Posted: Sun Jan 04, 2015 9:10 am Post subject: |
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The gear in your photo has been SEVERELY overheated .. to the point that the imprint of the needles is clearly evident, and even the main gear teeth are on the verge of failure. When a gear is heated to this point, even steel will fuse to steel, so it's no wonder a soft part like a bare brass synchro ring will suffer. Early Bug TRANSAXLES don't ever reach this temperature in normal operation.
Again, what is the vintage of the MB bus TRANSMISSIONS you are documenting?
.. and what is the oil temperature in these TRANSMISSIONS?
I'd have no problem running GL-4 in an early TRANSMISSION, because it doesn't contain a hypoid R&P like a TRANSAXLE does. _________________ aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
https://guardtransaxle.com |
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DencherD Samba Member
Joined: December 16, 2011 Posts: 43 Location: Sonora Ca.
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Posted: Tue Jan 06, 2015 1:15 pm Post subject: transmission fluid |
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Hey guys I've gone thru and read these posts and it made me confused on what fluid to put in my new Rancho transmission.So I asked Rancho....this is what I was told,
80-90 Hypoid Gear Lube. Just a good major brand Oil no synthetics |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50261
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Tue Jan 06, 2015 2:02 pm Post subject: Re: transmission fluid |
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Did you? The seconds one you listed is Synthetic. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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RichardLW Samba Member
Joined: December 28, 2014 Posts: 20 Location: Santa Cruz, Bolivia
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Tue Jan 06, 2015 2:07 pm Post subject: |
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RichardLW wrote: |
But it's an easy way out for someone who has no idea what he is talking about.
Worse yet whey he says no synthetics. He disqualified himself for future reference. |
Rancho Transmission probably rebuilds more VW transmissions than any other shop. And they have been around for years with many happy customers.
I put 100,000 hard miles on a Rancho tranny back in the 1980's _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare
Last edited by Glenn on Tue Jan 06, 2015 2:09 pm; edited 1 time in total |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50261
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Posted: Tue Jan 06, 2015 2:08 pm Post subject: Re: transmission fluid |
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Glenn wrote: |
Did you? The seconds one you listed is Synthetic. |
I agree it is a synthetic, but that is a irrelevant point as far as my post is concern. |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76760 Location: Sneaking up behind you
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Posted: Tue Jan 06, 2015 2:12 pm Post subject: Re: transmission fluid |
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Wildthings wrote: |
Glenn wrote: |
Did you? The seconds one you listed is Synthetic. |
I agree it is a synthetic, but that is a irrelevant point as far as my post is concern. |
Please explain your point since i'm missing where your posting a Syntheric when "no synthetics" was specified makes one. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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RichardLW Samba Member
Joined: December 28, 2014 Posts: 20 Location: Santa Cruz, Bolivia
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