Symthetic gear oil in the trans or not??

[c.v.helleri]

   To run synthetic gear oil in the trans or not??  GL4 or GL5??  I recently drained it and wanted to upgrade, but now i'm having second thoughts.  I need you input and the pros and cons.  Thanks  Doug S.

[Peter]

I used castrol LSD synth oil,
the only lsd oil that i could find,
Its still ok it seems, no leaks either
I called castrol and they said it should work fine allthough its designed for use in BMW diffs

[wolfswest]

I used castrol LSD synth oil,
the only lsd oil that i could find,
Its still ok it seems, no leaks either
I called castrol and they said it should work fine allthough its designed for use in BMW diffs

Yes, that's fine because you have a LSD, I don't know if c.v. helleri has a LSD?  If not I wouldn't use LSD oil...

[c.v.helleri]

  Thank you both for stepping up with info.  I've come to the conclusion that the GL5 will be ok after what I've read on another site by Bruce Tweddle.  Tha.nks again  Doug S

[Bruce]

.......allthough its designed for use in BMW diffs

BMW diffs are made by ZF.

[RMS Boxer Service]

LAT 80W90 oil for a stock transmission or 75/140 for performance transmission/Mendeola. LAT oil is made by
some hardcore VW guys in the USA (Geers, Rancho). These oils are for normal diffs, not for ZF limited slip diffs.

http://www.lubeatech.com


/Rolf

[Harry/FDK]

GL4

[Bruce]

GL4

That may be ok for a stocker, but when you're pushing 4-5 times as much hp as the gearbox was designed for, you need the higher extreme pressure rating that GL-5 has.  Otherwise you're going to prematurely wear out plenty of German made trans parts.  When those parts are gone, you'll be getting CHINA parts as replacements.

[TexasTom]

We told that GL4 was the lube to use for synchro T1/2 transaxles because it was more compliant with the synchros and GL5 was 'too slippery' which could cause damage to them. The GL5 doesn't allow the synchros to slow the gearstack down effectively causing undue wear to the assembly.
We use GL4 in T1/2 tranaxles and GL5 in the watercooled stuff.
I certainly don't consider myself an expert in this arena, just what we were told to use.

I await Bruce's lecture ... 

[Dominick Luppino]

LAT 80W90 oil for a stock transmission or 75/140 for performance transmission/Mendeola. LAT oil is made by
some hardcore VW guys in the USA (Geers, Rancho). These oils are for normal diffs, not for ZF limited slip diffs.

http://www.lubeatech.com/index.html


/Rolf

X2, that's what I use.

[Bruce]

. The GL5 doesn't allow the synchros to slow the gearstack down effectively causing undue wear to the assembly.
.

  If GL-5 makes the synchros not work, it will show up as grinding gears.  Who is experiencing that?

We use GL4 in T1/2 tranaxles and GL5 in the watercooled stuff.

Watercooled cars have synchros too.  Why is GL-5 ok in them and not in a T1 or T2 gearbox?

Can you post your pics of synchros damaged by GL-5?

[TexasTom]

Again, I'm no expert on transmissions, I can only post the following information:

As per Robert Bentley VW Service manual, T1 70-79; Lubrication and maintenance, Section 2. Lubricants ... paragraph 3
"The lubricants used in your VW have a vital influence on its operation. ... The hypoid oil used both in the manual transmission and in the Automatic Stick Shift must meet specification MIL-L 2105 API/GL4. ..."

Certainly not trying to be a smartas*, just saying this is why we use what we do.
For customers that prefer synthetic, we use Redline MT90 for T1/2s, MTL for watercooleds.
Also, I stand corrected on the GL5 for watercooleds ... we also use GL4 in them as well, I was wrong. I believe GL5 is more often specified for use in rear-wheel drive differentials.
That's all I know and so all I can say.

[Bruce]

Again, I'm no expert on transmissions, I can only post the following information:

As per Robert Bentley VW Service manual, T1 70-79; Lubrication and maintenance, Section 2. Lubricants ... paragraph 3
"The lubricants used in your VW have a vital influence on its operation. ... The hypoid oil used both in the manual transmission and in the Automatic Stick Shift must meet specification MIL-L 2105 API/GL4. ..."

Written before GL-5 existed.
GL-4 is fine in a stock application.  Many of us are 2-3-4-5 times as much hp as the trans was designed for.  GL-5 gives you much higher extreme pressure rating to deal with the higher stress.

Even if you believe the myth, there's $40 worth of synchros in your trans that you'll be "saving" with GL-4.  The rest of the parts are much more valuable, and most are NLA.  Those other parts will be prematurely worn out with GL-4's inferior extreme pressure rating.

[TexasTom]

The last rating given to any VW transaxle that I have found, before VW switched to synthetic gearlube, was always GL4. Even the higher power VR6 machines (~ 4 times the hp rating of a T1).

[Torben Alstrup]

Hello.
I have to line up beside Bruce.
- I have tried A LOT of different gear oils over time. And as with engine oils there are very much of a difference between the brands and types.
I use, and have been for about 10 years now, Pennzoil 80/90 mineral gear oil in most applications. I found that the transmission noise was reduced and shifting was EASIER than with most other oils.
- The same oil in a T3 transporter makes the shifting sluggish, at least in cold weather, and it slows the syncro´s down somewhat. especially between 2nd and 3rd. The T3 "needs" a slightly thinner oil because of the slightly different set up with the syncro´s. In these cases I have used Agip, Castrol and Shell oil. But have never gotten reports of the inside of these subsequent. So in that case the one can be as good as the next.

- For people that needs least powerloss through the gears I have been using same brand (Pennz oil) 75/90 synthetic along with a bottle of Abbcon (Nulon but better) friction reducer. One of these trannys sits in a 215 hp autocrosser (or dirt tracker on the US side) and has been apart twice for inspection and freshening up. There are no signs of unusual wear on the gears nor the syncro´s. In fact they survive very well.

- I want to try Brad Penn´s gear oils as soon as I get the time for it.
T

[Bruce]

Even the higher power VR6 machines (~ 4 times the hp rating of a T1).

Do they use a transmission that was only designed for ¼ of what the engine puts out?  Do they use an transmission with metalurgy from 40 years ago?
The wear I have seen on Type 1 transmission parts proves that the lubrication characteristics of the oil is inadequate.

What do you fear with using GL-5?