GL-4 and GL-5 revisited

[moribundman]

Much has been said about those two, but I'd like to add some more:

1. BP says a Torsen needs GL-5
2. BP says most manual transmissons need GL-4, because GL-5 is too slippery for the synchros

My Audi quattro uses the same fluid (SAE 75W-90) for the transmission and the Torsen. I don't know if Gl-4 or GL-5 spec oil is required. Audi wants to sell their own outageously overpriced fluid (Approaching $30 for a quart). From what I've been told, GL5 is not recommned in the transmission, but according to BP, the Torsen needs GL-5. Since transmission and Torsen share the same fluid, I'm wondering what the deal is. Is there a definite answer?

 

[jsharp]

Do they require GL-4 because GL-5 is "too slick" or because of brass or bronze components that might be damaged by GL-5? Or is the recomendation GL-4 or better??

For instance my Toyota calls for GL-4, but also allows GL-5.

There was a note about this on the Mobil site and they claimed IIRC that there wasn't a "too slick" problem, but might be a corrosion issue in some applications.

What does the manufacturer say?

[ July 31, 2003, 04:17 PM: Message edited by: jsharp ]

 

[moribundman]

Audi insists on using their "own" (Pentosin?) fluids. Audi doesn't say if the synthetic transmission fluid is supposed to be GL-4 or GL-5 (for the rear differential they specify GL-5).

Most Audi owners advised me to use GL-4 in the transmission. Now, I've read the Torsen needs GL-5. I've previously mentioned the possibility of GL-5 causing corrosion problems with the synchros, but some of the oil gurus here told me that problem didn't exist with the new GL-5 lubes.

Audi has changed the part number for their transmission fluid. Maybe someone knows what it really is:

Part number back in '96: G 052 911A
Current part number: G 052 911 A2

 

[jsharp]

quote:

---

Originally posted by moribundman:
Audi insists on using their "own" (Pentosin?) fluids. Audi doesn't say if the synthetic transmission fluid is supposed to be GL-4 or GL-5 (for the rear differential they specify GL-5).

Most Audi owners advised me to use GL-4 in the transmission. Now, I've read the Torsen needs GL-5. I've previously mentioned the possibility of GL-5 causing corrosion problems with the synchros, but some of the oil gurus here told me that problem didn't exist with the new GL-5 lubes.

Audi has changed the part number for their transmission fluid. Maybe someone knows what it really is:

Part number back in '96: G 052 911A
Current part number: G 052 911 A2

---

Audi can "insist" all they want but they either have to provide you with a specification for the fluid so you can use an equivilent, or provide you with fluid free of charge...

[ July 31, 2003, 08:04 PM: Message edited by: jsharp ]

 

[moribundman]

Next time I go to the stealer's parts department I'll find out.

Not sure about if they have to provide me with specs. It's the same with VW/Audi (and BMW) power steering fluid. We have to use Pentosin 11s, if we want or not. I'm not aware of a suitable aftermarket product (Pentosin 11s is not regular P/S fluid). Same with G12 and G12 Plus coolant (also made by Pentosin).

 

[instigator]

what jsharp was getting at was it is the magnuson act that makes the dealers divulge the info and if not then they have to provide you with the item for free(in your case transmission fluid) iirc

[ August 01, 2003, 10:50 AM: Message edited by: instigator ]

 

[Ken2]

It's also the case that there may be only one supplier that meets the spec. Castrol's Transynd for an Allison transmission or Daimler-Chrysler's ATF +4 are a couple of examples.


Ken

 

[moribundman]

quote:

---

It's also the case that there may be only one supplier that meets the spec.

---

Yeah, Magnussen Act (I'm not a lwayer - I don't even play one on TV

) or not, if there's according to the car maker only an OEM fluid that meets their specs, then they may well have created sort of a monopoly.

As I've said, I'll try again.

 

[FowVay]

Not to be splitting hairs here but the VW coolant is a patented Glysantin product but Pentosin does make a comparable fluid. In North America the dealer provided coolant is made by Ashland chemical (Zerex) under license from BASF, the parent of the Glysantin name.

Also, on my E46 BMW there is nothing stating the use of Pentosin CHF11s fluid. My manual and power steerin reservoir cap specify automatic transmission fluid. I was told to use a synthetic blend ATF such as Mercon V or Multi-Vehicle ATF which is a synthetic blend when topping off the power steering reservoir.

 

[moribundman]

FowVay,

As far as I know, Pentosin is one of the makers, if not THE maker of OEM fluids for German car manufacturers.

I'd love to get my hands on some OEM spec fluids that I do not have to buy from the dealer!

 

[Dr. T]

Well, my 1994 BMW does say Pentosin 11s on the cap for the Hydraulic system. Using anything else will cause leaks everywhere and a $2-3k repair bill.

Some BMW's (like my friends 1988 325) do use Dexron for the PS/Hydraulic systems...be careful!

The 11s is ~$30 Can. at the local stealer. I've seen it at aftermarket places/performance shops too. The thing that sucks is you could probably buy it OTC in Europe....probably at WalMart.

 

[moribundman]

Dr. T,

Parts (including fluids) are usually not as overpriced at the dealer in Europe as they are in NA. Of course, they got those exorbitant gas and oil prices...

I just found Pentosin 11s online (BMW parts site) for just under US $21. Unfortunately they don't say if that's a 1 liter bottle. It could be less.

Some Napa stores carry Pentosin G12 and Pentosin 11s, too.

 

[Ray H]

Just to split hairs, there's no "t" in "Dexron"...

 

[harrydog]

So would using a GL-4 in a transmission that calls for GL-5 be a problem?
My Subaru calls for 75w90 GL-5 but I'd like to try Redline MTL-90 which is a GL-4. Others have had good luck with it. I'm also interested in using Redline Shockproof which is also a GL-4.

 

[MolaKule]

Harrydog,

Here is my recommendation:

Sample current MT fluid and do a used oil analysis.

Install Redline MT-90, sample at 7,500 miles and do another used oil analysis and compare
wear metals.

In this case, I would use MT-90 full strength with no mixing with any
other products.