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gears
Samba Member
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Location: Tamarack, Bend, Kailua
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 Posted: Wed Aug 19, 2015 1:09 pm Post subject: |
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Porsche presently uses the exact same type of Borg Warner moly-coated brass synchro ring that your '83 Van uses (in all their "street" models).
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aka Pablo, Geary
9.36 @ 146 in '86 Hot & Sticky
'90 Syncro Westy SVX
'87 Syncro GL 2.5
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mrcool
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Location: Bozeman, MT
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| Posted: Wed Aug 19, 2015 1:17 pm Post subject: |
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OK cool. Because it is moly coated though the GL5 won't have any affect.
Help me figure out how realistic this concern is. Still under the assumption of original power and tranny. I know this isn't realistic but lets assume that shifting is perfect and that does not introduce wear.
My concern:
GL5 CAN cause corrosion. Wouldn't corroded metals wear faster in this application? This could cause particles in the case that could wear the R&P? if it is not causing particles to float in the case it is hurting the surface of the syncro and potentially whatever meshes with it. |
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gears
Samba Member
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Location: Tamarack, Bend, Kailua
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| Posted: Wed Aug 19, 2015 2:00 pm Post subject: |
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| mrcool wrote: |
OK cool. Because it is moly coated though the GL5 won't have any affect.
Help me figure out how realistic this concern is .. <snip> .. |
Your concern is unrealistic.
Both Porsche and VW have installed BARE brass synchro rings on top gear for decades. Despite the fact that top gear runs at a higher temperature than any other gear, none of these synchro rings is prematurely failing, regardless of GL type. (Note: VW's rebuild procedure calls for moly synchro for top gear.)
In the spirit of full disclosure, there was a complaint of GL-5 ruining the moly coated synchros used in rebuilds a few years back .. but IMO this was a specific bad batch of VW Aftermarket synchro rings, paired with a poor choice of GL-5. I say this because moly-coated 002 rings have been available for 30+ years, yet the issue never surfaced previously .. and I haven't heard the complaint recently.
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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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EVfun
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| Posted: Wed Aug 19, 2015 2:05 pm Post subject: |
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I would think the high gear syncro has the easiest job of them all. The rpm difference between the top 2 gears is usually smaller than any lower gears. A syncro is a type of clutch that speed matches the gear speed to the shaft speed before the hub connects them.
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gears
Samba Member
Joined: October 28, 2002
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Location: Tamarack, Bend, Kailua
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| Posted: Wed Aug 19, 2015 3:30 pm Post subject: |
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Absolutely true. The bean counters saved $3 because there's no down-shifting into 5th. However, the point remains that top gear, subjected to far more heat than any other gear, should suffer from the "peeled material" syndrome. It doesn't. .. unless it's been grossly overheated. But far worse symptoms than damaged brass synchro are evident at this point.
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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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mrcool
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Joined: April 01, 2015
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Location: Bozeman, MT
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| Posted: Wed Aug 19, 2015 3:41 pm Post subject: |
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| gears wrote: |
| mrcool wrote: |
OK cool. Because it is moly coated though the GL5 won't have any affect.
Help me figure out how realistic this concern is .. <snip> .. |
Your concern is unrealistic.
Both Porsche and VW have installed BARE brass synchro rings on top gear for decades. Despite the fact that top gear runs at a higher temperature than any other gear, none of these synchro rings is prematurely failing, regardless of GL type. (Note: VW's rebuild procedure calls for moly synchro for top gear.)
In the spirit of full disclosure, there was a complaint of GL-5 ruining the moly coated synchros used in rebuilds a few years back .. but IMO this was a specific bad batch of VW Aftermarket synchro rings, paired with a poor choice of GL-5. I say this because moly-coated 002 rings have been available for 30+ years, yet the issue never surfaced previously .. and I haven't heard the complaint recently. |
So I was talking about wear, not failure.
You don't think corroded gears would cause unnecessary wear on other gears? Unnecessary wear due to corrosion on the gear or introducing fragments into the case. I would guess that the corrosion would not be picked up by the magnet in the fill plug.
Thanks for bearing with me |
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gears
Samba Member
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| Posted: Wed Aug 19, 2015 3:52 pm Post subject: |
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Here it is on a platter for you: The use of a high quality GL-5 won't damage the bare brass 4th gear synchro ring in your '83 van's transaxle. Damage to these (of the type you're describing/imagining) only occurs (regardless of GL type) when the gear is grossly overheated.
_________________
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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mrcool
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| Posted: Wed Aug 19, 2015 3:59 pm Post subject: |
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| Hmmm ok, thanks. |
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mrcool
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| Posted: Wed Aug 19, 2015 4:11 pm Post subject: |
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| So then why do we care if brass corrodes with GL5? |
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gears
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| Posted: Wed Aug 19, 2015 5:17 pm Post subject: |
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No one in Porsche world does. I don't. Other old time VW guys in this thread don't. So far as I know, the main VW trans shops don't. Which VW transaxle shops DO concern themselves specifically with GL-5 brass corrosion?
Keep in mind that we're talking generally now, as there are high quality GL-5 gear lubes readily available that are specifically known to be more "brass friendly" than your average GL-4.
_________________
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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mrcool
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| Posted: Wed Aug 19, 2015 5:23 pm Post subject: |
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That is interesting.
So what on their spec sheet will tell me if its brass friendly?
What do I need to look at in a GL5 to find that it is more suitable. |
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mrcool
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| Posted: Fri Aug 28, 2015 12:47 pm Post subject: |
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FWIW I went with Sta-Lube SL24239 API/GL-4 Multi-Purpose Hypoid Gear Oil.
200 miles and everything shifts like it should.
I have not seen any evidence that GL-5 is better to use for this application. only evidence that it can corrode gears. There is also no way to tell (without going to the supplier) that a particular GL5 is a safe one to use. |
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Glenn 
Mr. 010
Joined: December 25, 2001
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| Posted: Fri Aug 28, 2015 12:52 pm Post subject: |
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| mrcool wrote: |
| only evidence that it can corrode gears. |
Can I see this evidence? And let it not be old evidence.
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
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mrcool
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| Posted: Fri Aug 28, 2015 1:04 pm Post subject: |
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I am not saying it corrodes our syncros to the point of failure. Don't worry
Every single person agrees that yellow metals will corrode. Again, I am talking about yellow metals on their own. If there is a coating on the syncro, great.
No one seems to be able to answer how to find a brass friendly, high quality GL-5 from a data sheet. Or for that matter if stock transmission even need the high extreme pressure rating of GL-5. Currently, by everyone's logic we should just go with gear oil that is used with drilling machines since we need the highest pressure possible to preserve NLA parts. (yes i am exaggerating..  ) |
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Glenn
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| Posted: Fri Aug 28, 2015 1:12 pm Post subject: |
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| mrcool wrote: |
I am not saying it corrodes our syncros to the point of failure. Don't worry
Every single person agrees that yellow metals will corrode. Again, I am talking about yellow metals on their own. If there is a coating on the syncro, great.
No one seems to be able to answer how to find a brass friendly, high quality GL-5 from a data sheet. Or for that matter if stock transmission even need the high extreme pressure rating of GL-5. Currently, by everyone's logic we should just go with gear oil that is used with drilling machines since we need the highest pressure possible to preserve NLA parts. (yes i am exaggerating.. ) |
You made a declarative statement that you have seen evidence... i just want you to share it.
| mrcool wrote: |
| I have not seen any evidence that GL-5 is better to use for this application. only evidence that it can corrode gears. |
In other words... put up or shut up.
As to how to find safe GL5.... easy, just ask the guy that built your tranny. My guy, Gary Berg, said to use Valvoline, so I am.
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Glenn
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mrcool
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| Posted: Fri Aug 28, 2015 3:10 pm Post subject: |
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OK so my "evidence" is as anecdotal as yours. It just so happens that my anecdotes are backed by multimillion dollar R&D facilities and the entire industry that says it will corrode yellow metals. But they are probably wrong. It probably doesn't corrode...
| Quote: |
As to how to find safe GL5.... easy, just ask the guy that built your tranny. My guy, Gary Berg, said to use Valvoline, so I am. |
You need to stop getting so defensive because you can't justify what you believe so strongly in with no evidence. Your justification is "some guy that's really good at it told me so and no one has complained". Did you also see that Valvoline said that the Valvoline VV831 corrodes yellow metals? Like I have said several times before, maybe HIS rebuilt transmissions are suitable for GL5. I do not believe a stock transmission is.
If you would like to put up and evidence that a stock trany with stock motor needs GL5 I am all ears I will more than happily switch out to GL5 no matter how badly transmission fluid stinks up the place.
Show me:
1) A stock 091 tranny and matching motor needs the extreme pressure additives of GL5 to protect the NLA parts. Or that GL4 does not have suitable EP additives.
2) How to find a GL5 that is brass safe - what to look for on the data sheet.
3) My syncro gears are coated and will be protected from the reactive sulfur. I have seen replacements are moly coated but that's it.
Can you actually not agree that these are questions that need to be answered to make an independent (not hear say) opinion on what oil to use? |
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Bruce
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| Posted: Sat Aug 29, 2015 1:59 pm Post subject: |
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| mrcool wrote: |
| Every single person agrees that yellow metals will corrode. |
WRONG!
The oil suppliers say some additives "may" cause corrosion. Since I have never seen this mythical corrosion, I conclude the warning is false.
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Bruce
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| Posted: Sat Aug 29, 2015 2:08 pm Post subject: |
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| mrcool wrote: |
[b]Show me:
1) A stock 091 tranny and matching motor needs the extreme pressure additives of GL5 to protect the NLA parts. Or that GL4 does not have suitable EP additives. |
Let's say you're cleaning out your garage and that spare 091 gearbox under your work bench now has to go. So you load it up and take it to Dave Folts Transmissions (or Rancho) so you can sell it to them for their core charge. They are glad to see it, but as you stand there with your hand out you wonder why they aren't handing you a stack of bennys. The reason is they first have to pull the bell housing off to inspect the ring and pinion. Because the vast majority of them are JUNK! Made so by people like you who used inferior GL-4 oil that allowed metal to metal contact.
GL-5 is better able to prevent this metal to metal contact.
| mrcool wrote: |
| 2) How to find a GL5 that is brass safe - what to look for on the data sheet. |
Why not look at the parts that were used with GL-5?
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| overheard at the portland Swap Meet... wrote: |
| ..... a steering wheel made from a mastadon tusk..... |
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mrcool
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Location: Bozeman, MT
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| Posted: Sat Aug 29, 2015 2:14 pm Post subject: |
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| Bruce wrote: |
| mrcool wrote: |
| Every single person agrees that yellow metals will corrode. |
WRONG!
The oil suppliers say some additives "may" cause corrosion. Since I have never seen this mythical corrosion, I conclude the warning is false. |
You love taking stuff out of context. I said it will corrode yellow metals. And sure there may be some GL5s that do not corrode. But you have yet to provide anything that shows how to find a suitable GL5. Are you using your naked eye? What sort of gears are you inspecting? Are you looking at original stock syncros that have used GL5 for 100k miles?
Why don't you answer my questions? It will be a lot more productive in making me shut up 
1) A stock 091 tranny and matching motor needs the extreme pressure additives of GL5 to protect the NLA parts. Or that GL4 does not have suitable EP additives.
2) How to find a GL5 that is brass safe - what to look for on the data sheet.
3) My syncro gears are coated and will be protected from the reactive sulfur. I have seen replacements are moly coated but that's it.
edit: awesome just saw your post i'll read it after a pool party |
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mrcool
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Posts: 358
Location: Bozeman, MT
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| Posted: Sat Aug 29, 2015 2:29 pm Post subject: |
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| Bruce wrote: |
| mrcool wrote: |
[b]Show me:
1) A stock 091 tranny and matching motor needs the extreme pressure additives of GL5 to protect the NLA parts. Or that GL4 does not have suitable EP additives. |
Let's say you're cleaning out your garage and that spare 091 gearbox under your work bench now has to go. So you load it up and take it to Dave Folts Transmissions (or Rancho) so you can sell it to them for their core charge. They are glad to see it, but as you stand there with your hand out you wonder why they aren't handing you a stack of bennys. The reason is they first have to pull the bell housing off to inspect the ring and pinion. Because the vast majority of them are JUNK! Made so by people like you who used inferior GL-4 oil that allowed metal to metal contact.
GL-5 is better able to prevent this metal to metal contact.
| mrcool wrote: |
| 2) How to find a GL5 that is brass safe - what to look for on the data sheet. |
Why not look at the parts that were used with GL-5? |
I couldnt resist...
So I don't really consider that evidence as to why GL5 is protecting the NLA parts. How much pressure are those gears actually under? Is it so much pressure that GL4 will actually allow for metal to metal contact?
While it will probably depend on maintenance and driving style more so than GL4 vs 5 I am curious if you have used brand new ring and pinion parts (back in the day), put the same miles on them using GL5 and actually seen reduced wear. I feel like if that is the case it should be easy to post up "evidence" of lesser wear. Is it really the EP additives that are preventing metal on metal contact in this instance?
question 2:
Just because another manufacturer used gl5 with similar syncros (someone used porsche as an example) doesn't show me that it is brass safe.
So what about question three? What is the metal composition of the stock syncro gears in a 1980 091 tranny? If I could 100% rule out the possibiliy of wear or corrosion on them with gl5 it would make my decision of using gl5 a lot easier |
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