TheSamba.com :: View topic - GL 4 or GL 5

Sun Aug 12, 2012 6:53 pm

Bruce wrote: You still don't know what a hypoid gear is, do you?

I have known what a hypoid gear is for close to 50 years at this point, and know that VW bus manual boxes have a small displacement between the axes.

From Wikipedia:

Quote: API GL-4. Oils for various conditions - light to heavy. They contain up to 4.0% effective anti-scuffing additives. Designed for bevel and hypoid gears which have small displacement of axes, the gearboxes of trucks, and axle units. These oils are standard for synchronized gearboxes, especially in Europe, and may also be recommended for non-synchronized gearboxes of US trucks, tractors and buses and for main and other gears of all vehicles. GL-4 oils may also be used in many limited-slip differentials.

API GL-5. Oils for severe conditions. They contain up to 6.5% effective anti-scuffing additives. The general application of oils in this class are for hypoid gears having significant displacement of axes, generally non limited-slip differentials. They are recommended as universal oils to all other units of mechanical transmission (except synchronized gearboxes specifying GL-4). Some GL-5 oils in this class, which have special approval of vehicle manufacturers, can be used in synchronized manual gearboxes. API GL-5 oils can be used in limited slip differentials only if they correspond to the requirements of specification MIL-L-2105D or ZF TE-ML-05. In this case the designation of class will be another, for example API GL-5+ or API GL-5 LS.

If these trannies were all going to blow apart running GL-4 few would still be usable with 40'ish years on them. I have seen my share of gear boxes fail running GL-5 and lots of other oils.

The MIL-L-2105 spec is the spec for GL-4 oil. This is what VW called for in bus and bug trannies from '74 onward. They had earlier specced MIL-L-2105-B (GL-5) oils, but changed to the GL-4 likely because GL-5 was giving problems.

Thu Aug 16, 2012 8:48 am

How do you feel about slick 50 75-90 Syn? I have no clue on how old my gear lube in my tranny is and I have 4 bottles of slick 50.

Thu Aug 16, 2012 8:58 am

Beatles_1969 wrote: How do you feel about slick 50 75-90 Syn? I have no clue on how old my gear lube in my tranny is and I have 4 bottles of slick 50.
Don't use it... it's been proven to be snake oil.

Fri Aug 17, 2012 9:12 pm

Read up on the specs for MIL-L-2105-B or C or D or E or MIL-PRF-2105E. They can be found online if you do a little searching. They are supposedly backwards compatible and very specifically mention minimizing corrosion of yellow metals (the very arguement used against GL-5 rated oils). VW changed their specifications from MIL-L-2105B to MIL-L-2105/GL4 at some point in the 70s. The only explanation I have found is in a Official Workshop Bulletin (printed in Germany) dated 31 August 1977.

"There are two different oils prescribed for the lubrication of manual gearboxes and final drives, these are:

Hypoid gear oil SAE 80 or 80W90 according to MIL-L2105
Hypoid gear oil SAE 90 according to MIL-L2105 B.

Because the MIL specification are not shown on the oil containers and the mineral oil companies use various brand designations, confusion is often the case. This in turn leads to extensive damage and expensive repairs to the gearboxes.

To prevent these difficulties in the future, we have requested the mineral oil industry to use the following uniform designations:

GL 4 for Hypoid gear oil according to MIL-L 2105
GL 5 for Hypoid gear oil according to MIL-L 2105 B."

It goes on to list what vehicles use which oil where and even has a list of approved limited slip oils.

I honestly have no idea why VW changed the oil specification. Frankly, it doesn't make sense to me since 2105B supersedes and is supposedly backwards compatible with 2105. I started poking around my repair manuals some and to be honest, it was inconsistent. I have specification pages from 1969 that call for 2105B in all transmissions (type 1,2,3, 181) and then others in 1973 that call for it in some (181) and straight 2105 in others. Right around 1975 is when VW seems to have started calling for 2105/GL4 for all manual transmissions (vehicles with separate final drives call for 2105B/GL5 in the final drive). The exception is the type 4 manual transmission which calls for GL5/2105B.

I forget what oil I used when I changed the transmission fluid in the 181, but I do know that I did a bunch of searching until I found one that specifically said it met 2105B.

Fri Aug 17, 2012 11:26 pm

Wildthings wrote:
From Wikipedia:

Quote: API GL-4. Oils for various conditions - light to heavy. They contain up to 4.0% effective anti-scuffing additives. Designed for bevel and hypoid gears which have small displacement of axes, ......

API GL-5. Oils for severe conditions. They contain up to 6.5% effective anti-scuffing additives. The general application of oils in this class are for hypoid gears having significant displacement of axes, g......
This is good info.
If you call up any VW trans builder and ask how often they see Bus 091s with worn out R&Ps, they will tell you it is VERY COMMON. The high incidence of failed R&Ps proves that GL-4 is insufficient at protecting the gears. The last time I was at Dave Folts shop, he had a couple of pallets of Bus 091 cores. Before he pays for them, he pulls the bell housings off for an inspection. If worn out R&Ps were an unusual occurrence, he wouldn't bother checking them.

Wildthings wrote: I have seen my share of gear boxes fail running GL-5 and lots of other oils.
We've already established earlier that you've never seen the insides of a gearbox, so how can you diagnose the cause of any gearbox failure?
Let's see some photos of these failed gearboxes.

Sat Sep 01, 2012 4:43 am

This thread hurts my head #-o #-o

I have had great results using Redline MT-90 in my other vehicles,and I will use it in my 72 Karmann Ghia. It is a GL 4 spec oil, and I am happy with that.
I did forget however how much oil I need for my transmission. How much oil is needed for my stock transmission?

Thanks,
Zack

Fri Sep 07, 2012 6:38 pm

Bruce wrote:
We've already established earlier that you've never seen the insides of a gearbox, so how can you diagnose the cause of any gearbox failure?

When did you establish this bit of misinformation?

Wed Sep 12, 2012 9:47 am

Just for the heck of it, I read threw this entire thread from beginning to end, and its actually pretty funny. I don't understand why people, with the exception of those that don't wan't to void their warranties, don't just run GL5 for crying out loud.

Some people are just so diehard to what the old papers say that they miss out on the finer things. I'm all for keeping an old bug original, but good grief... Better oils exist now days. GL5 is sold for the same price as GL4 in many stores. I just don't understand the argumet of those so in favor with it.

If you wan't to use GL4, fine, it works...but saying not to use GL5?...thats just over the top and illogical.

As for me, I took the GL5 :D

Wed Sep 12, 2012 8:03 pm

Vanapplebomb wrote: Just for the heck of it, I read threw this entire thread from beginning to end, and its actually pretty funny. I don't understand why people, with the exception of those that don't wan't to void their warranties, don't just run GL5 for crying out loud.

Some people are just so diehard to what the old papers say that they miss out on the finer things. I'm all for keeping an old bug original, but good grief... Better oils exist now days. GL5 is sold for the same price as GL4 in many stores. I just don't understand the argumet of those so in favor with it.

If you wan't to use GL4, fine, it works...but saying not to use GL5?...thats just over the top and illogical.

As for me, I took the GL5 :D

Now that you are the expert, tell me if I have Joe down at Big Bubba's Garage change out my tranny fluid for me will their GL-5 hurt my synchronizers or not?

BTW there is nothing more modern about GL-5 compared to GL-4, the two specs came into use at about the same time.

Thu Sep 13, 2012 7:57 am

Wildthings wrote: Now that you are the expert

Not that your anecdotal 'evidence' has made you one either...

I think it was Jason who once said "the standards for being an expert around here are pretty low." That pretty much sums up both oil threads.

Thu Sep 13, 2012 9:19 pm

miniman82 wrote: Wildthings wrote: Now that you are the expert

Not that your anecdotal 'evidence' has made you one either...

I think it was Jason who once said "the standards for being an expert around here are pretty low." That pretty much sums up both oil threads.

So prove to me that no GL-5 oil in production today will harm my synchronizers.

Thu Sep 13, 2012 10:27 pm

Wildthings wrote: So prove to me that no GL-5 oil in production today will harm my synchronizers.

What do you want me to do, borescope my transmission? :roll: I don't tear them apart unless there's a problem, maybe you should come back with some confirmed (read: PHOTOGRAPHIC) proof of all this supposed damage. I'm not nice to my engines or transmissions, stands to reason if the oil was bad for it I'd have broken something by now. Never mind the fact that my clutch cable has been loose for at least a year, which puts strain on synchro rings. Still not a peep from the gearbox.

Fri Sep 14, 2012 11:39 am

miniman82 wrote: Wildthings wrote: So prove to me that no GL-5 oil in production today will harm my synchronizers.

What do you want me to do, borescope my transmission? :roll: I don't tear them apart unless there's a problem, maybe you should come back with some confirmed (read: PHOTOGRAPHIC) proof of all this supposed damage. I'm not nice to my engines or transmissions, stands to reason if the oil was bad for it I'd have broken something by now. Never mind the fact that my clutch cable has been loose for at least a year, which puts strain on synchro rings. Still not a peep from the gearbox.

You don't have to look in your transmission at all, just provide some reasonable proof that all GL-5 oils out there have been reformulated to not hurt yellow metal. I don't even care about oils from the bush of South America, or the dark heart of Africa, so you can limit your proof to oils sold in the US.

It is great that some people buy such and such expensive oil, but many buy the first oil they find, others the cheapest oil they can come up with, and still others just depend on their local garage to supply whatever brand X oil they have on hand. When you guys claim that GL-5 oils will not damage synchros you need to show that you claim covers all GL-5 oils not just a select few.

Fri Sep 14, 2012 12:08 pm

I can't prove a negative (no damage), that's as silly a statement as I've ever heard. Much easier to prove that it did in fact damage something, so the onus is on you not me. There's nothing wrong with my transmission, and I run GL5.

Fri Sep 14, 2012 12:22 pm

miniman82 wrote: I can't prove a negative (no damage), that's as silly a statement as I've ever heard. Much easier to prove that it did in fact damage something, so the onus is on you not me. There's nothing wrong with my transmission, and I run GL5.

It is not proving a negative, and I don't care what oil is in your transmission, just show reasonable proof that all GL-5 oils sold in the US will not hard yellow metal or you and other should quit making the claim that GL-5 oils are okay to run. Buy the oils, run the tests, get the oil analysis, or don't make the claim.

Fri Sep 14, 2012 12:24 pm

Prove that are not. 99% of all shops use GL5 so where's the thousands of bad sycnros because of GL5?

Just show me one.

BTW... i've posted this before and am sure nothing will change your mind.

Fri Sep 14, 2012 12:56 pm

Glenn wrote:

Prove that are not. 99% of all shops use GL5 so where's the thousands of bad sycnros because of GL5?

Just show me one.

BTW... i've posted this before and am sure nothing will change your mind.

So your post shows that many automobile manufactureres admit there is a problem with generic GL-5 oils causing synchro damage, and Swepco says that their expensive oil have been modified to not cause this well known problem. I am in agreement there as I have never said anything differently, but that only leaves dozens of other oils out there for you to check, keep at it.

Quote: BTW... i've posted this before and am sure nothing will change your mind.

Contrary to your guys repeated statements otherwise I am very open minded about this. That is why I have tried several GL-5 over the years, but some has given me problems that I don't want to have repeated, and no I will not swap over to a generic GL-5 and risk ruining another set of synchros just to get you some pictures, but I will let you know if I ever have excessive ring and pinion damage from running any oil I choose to run, just don't hold your breath.

As for 99% of shops using GL-5, I have known more than one shop that have used GL-5 in trannys where other oils were specified and have ended up footing the bill to replace the tranny. That is an expensive place where I have no desire to go.

Fri Sep 14, 2012 1:09 pm

That statement is old. I know of a number of other GL5 oil that have said they are fine to use. Gary Berg specifies Valvoline when he rebuilds a tranny.

You're relying on old data.

Fri Sep 14, 2012 1:10 pm

Wildthings wrote: I have known more than one shop that have used GL-5 in trannys where other oils were specified and have ended up footing the bill to replace the tranny. That is an expensive place where I have no desire to go.
Pictures and names please.

Let's see your proof.

Fri Sep 14, 2012 2:11 pm

Wildthings wrote: It is not proving a negative, and I don't care what oil is in your transmission, just show reasonable proof that all GL-5 oils sold in the US will not hard yellow metal or you and other should quit making the claim that GL-5 oils are okay to run. Buy the oils, run the tests, get the oil analysis, or don't make the claim.

actually, yes it is you wanting him to prove a negative... only an idiot makes demands like that when they themselves have nothing but their opinion based on something they read in the past.... you show reasonable proof that *all GL-5 oil sold in the US* WILL cause damage, or don't make that silly claim.... turn-about, goose and gander, and all that stuff.... :wink: