Alfa Pages

[Brit01]

Strange.

After my engine rebuild (not touching the box) I put molykote anti-friction geabox additive in.

Now in 3rd and 5th gear I get a loud shhhhh noise. Only in these gears regardless of speed.

Sounds like a vacuum leak or a swirling liquid noise.
Very strange and worrying.

Could the additive be interfering with the bearings?

Can anyone shed any light on the noise?

Cheers
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[mg907]

My suggestion is:

Discard the mixed oil from your box and replace it with any gear oil that is compliant to the following specifications: SAE 80W90 API GL5 EP (Extreme Pressure) .

For example I use Agip Rotra MP 80W90 because I do not like additives.

Mario

[Brit01]

Yes I think I will just do that.

Agip is not available here.

What about Motul? Fully synthetic?
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Brit01]

Reading around and semi seems to be the preferred choice.

What size is the allen drain bolt?
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Bobkelso]

Hi,
when i changed gearbox oil I did the usual research about GL-4 and GL-5 oil
that every owner of old cars have to do, lacking clear information about it.

In the past GL-5 was know to be slightly corrosive to soft/yellow metals,
expecially when temperatures goes up, possibly damaging syncro rings and bushes
in gearboxes not compatible in only 20-30K kms/few years.
Commercial advises say GL-5 are now safe, because
they use less sulfur and more other addictives, and there are
oils with mild "GL4-5" specification, but still remain some doubs to me.

Problem was I don't know if there are yellow/soft metal in the 33 box like in some other older cars
(Ps.: here someone knows if syncros and bushes in 33 gearbox are iron or are soft/yellow metals?)

So I stayed on oil that was clearly signed as GL-4
(it has the same EP addictives of GL5 oils but with less concentration,
and it is still good for the hypoid gears of the 33 differential).

For simplycity I used castrol EP 80W-90 for manual transmission,
similar to original alfa specification. Working very fine. Being mineral
or semi synt it is not a luxury oil, so I'll change it every 60-70K Km
(I'm ok with that, as I prefer flush the gearbox quite often than one time evey many years).

Modern syntetic oils are probably better (I use always them for the motor)
but to use them in the gearbox I needed too much info research, because:

- usually they are 75W-90 grade, (also castrol does a GL-4 full synt 75-90)
but I didnt't know if syncros will work fine with a different gradation,
as syncros work using friction and 33 syncro are already weak working

Ps.: you can have the same problem if you use anti-friction addictives in the oil of the gearbox of an old type car,
syncros and bushes could not work correctly because of the sensible reduction of the friction

- many modern syntetic oil are ambiguos about GL5-GL4 specification/ corrosion of soft metals,
as it is not a big problem with modern gearboxes, so I didn't know if 33
syncros and bushes would be happy about it

If someones tryed some full synt 75W-90 oil I'll be happy to know how
is working (expecially syncros)!
_________________
Alfa 33

[Brit01]

Thanks Bob for the useful info.

We have Valvoline mineral 80w/90 here. Good based oil.
I added the Mlykote additive to the Valvoline. Before the rebuild it was fine.
Maybe the additive is conflicting with the valvoline.

Might just stick with that and it's not expensive available at every gas station.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Bobkelso]

Ok,
only verify that it is at least GL-4 (Exteme Pressure addittivation),
this is absolutely required for protect the hypoid differential gear
(high pressure on metals surfaces there),
as for every transaxle transmissions
(longitudinal motor -> there is a hypoid gear at the differential)
that use the same oil for differential box and gearbox.

Probably as sayd by Mario also GL-5 could work
(GL5 is a plus respect the required GL-4) but as I wrote I was
not sure about 33 gearbox metals resistance to sulfur addictives
(sorry, also today I scared a bit people )
so I stayed on old GL-4 (original alfa requirement).

But I'll be happy if someone say to me I was wrong, that he
used GL5 oil on 33 and after some years syncros are still perfects!
(or that syncros and bushes on 33 gearbox are all iron made,
so no soft/yellow metals problem there! )
_________________
Alfa 33

[Brit01]

ok good to know.

I'll have to go to a specialist supplier then as the garages that change the oil won't have a clue.

Motul molygear GL-4 or something like that.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Brit01]

Says here GL-5 is good for hypoid gears and for severe conditions.
This is what the boxer gears have no?



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.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Brit01]

Sprint manual says:

SAE 80W/90
API GL-5


Motul Gearbox sounds ideal.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[john 33_16v]

I think the gearbox drain and filler plugs are 12mm allen.

If the noise gets worse in 3rd and 5th it could be the rubber cotton reel bush at the linkage has a split just down one side thus affecting 3rd and 5th as opposed to all gears.

John
_________________
If it aint broke, fiddle with it until it is!
- - - - - - - - - - - - - -
93 33 16v Mirtle Met
08 Fiat Grande Punto Exotica Red
90 Yamaha FZR600 Genesis- Silky white/red/blue

[Brit01]

[john 33_16v]

At the end of the gear selector shaft coming out the back of the 'box is a plastic elbow where the remote control rod joins. It's in there- assuming s2 is the same set up as s3 which from memory i think it is??

John
_________________
If it aint broke, fiddle with it until it is!
- - - - - - - - - - - - - -
93 33 16v Mirtle Met
08 Fiat Grande Punto Exotica Red
90 Yamaha FZR600 Genesis- Silky white/red/blue

[Brit01]

ah yes with the pin at the top to hold the bushing in?

When the engine was removed that felt very firm and in good condition.

I did reduce the play in the 2 other small bushings that connects the stick to the push rod and tail.

Maybe too tight?

Nice precise changes though.

Well lets see if an oil change does anything.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Bobkelso]

Hi Brit,
About GL-4, it is not strong as GL-5 but it is used for hypoid gears in many cars
(where gl-5 is not compatible or in general when gearbox is separated from the differential box,
so you can put GL-5 only in the differential). May be GL-4 will not be as good instead
for something like hypoid gears "having significant displacement of axes"
(usually not the case of cars differentials, may be in heavy trucks)

Good to know that already the Sprint manual say GL-5,
because also manual of alfa 33 3th series say GL-5.
OK, probably it is completely safe use it because syncros
and bushes on 33 are made of iron and also I will use it next time,
my excuses also to Mario that suggested right oil alfa specification.

Still I'd like if anyone who rebuilded a 33 gearbox could confirm
no soft/yellow metals are present
My doubs was because at the time GL-5 was first used,
nobody did know the possible corrosion issue,
it was noticed by mechanics after some time and not admitted
by oil vendors until they started finding better composition,
with less sulfur, you can notice it by the fact they now GL-5 oils
don't smell so strong as before, and almost half of 33 gearbox
have syncros with short life, so I started suspect the first GL5 oils;
In internet I founded recent tests on metals, some new GL-5 where
showed very little aggressive, so safe, at ambient temperature,
but it was reported they became more active on metals when
temperature rises.

About your gearbox:
anti-friction addictive is one suspected,
but as John said the fact that the problem is present only in 3 and 5 gear
could also point to a mechanical alignment problem, at the bush he indicated
Ps.: or it is possible that for some reason the rod that connect the gear lever
to the command rod that exits the gearbox is now strong tilting/forcing by vertical angle on the gearbox
command rod when gear lever is moved forward (i.e. in 3a and 5a) so making
evident a small play already existing on the bush of the command road that exit gearbox??
_________________
Alfa 33

[Brit01]

[eagle3]

[Brit01]

These are the 2 bushings I modified to make it all tighter.
Maybe the #4 is causing the cotton bushing up front to put pressure on the inside causing the noise??
What do you think?

http://imageshack.us/photo/my-images/607/gearstickmounting2.jpg/

http://img607.imageshack.us/img607/7213/gearstickmounting2.jpg
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[eagle3]

It's the rubber bush 1 which deteriorates. And it's size changed slightly between series 2 and end of series 3.
_________________
Alfa33 QO 1984
Alfa33 1.3i.e. 1994

[Brit01]

This #1 bushing was fine before I put the engine back in.


_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Brit01]

Motul GearBox 80w/90 going in this weekend.

Discovered that the old oil they put in recently was not up to good standards due to my initial ignorance.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Brit01]

Will also check the bushing as you mentioned at the weekend. Probably have to jack up the car a bit to see that.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)

[Bobkelso]

Hi Brit,
I don't know if it can help,
but I think that the bush number 4 should be and remain of metal.
If you want to reduce the lateral/torsional play I'd prefer to add
(to the lateral plastic washers already present) one very thin
additional lateral washer on one side (ore two, one on both sides).
This additional washers should have inner hole bigger than the metal
bush diameter, so when you put the bolt, the metal bush
became stopped against the external fork, and the washers
can still rotate). But washers cannot bee too thick,
or you will lost the free rotation of washers and will have instead
the inner metal bush not firmly stopped against the fork and free
of rotate (and it should not) and the bolt not too much in tension.
In practice the tension of the bolt should go on (and only on)
the metal bush, the washers should only manage the torsion
and lateral play when using the gear level. In my 3th series
I used this principle to reduce the play, it was necessary only
a bit of patience in searching the 'perfect' washers

If you instead use rubber for the number bush 4,
probably the compression due to the bolt is acting on the washers
(as rubber also if strong is always a bit compressible) stopping free
rotation, maybe now that joint is doing a lot of friction when moving
the lever forward, consuming the plastic washers (in that case you will
have to re-torque the bolt quite often to avoid new play).

Ps.: less probable, but may be this is also doing some vertical pressure
on the gearbox command shaft when moving the gear lever forward,
giving the rumor you noticed?
(You would have the same effect of pressure/vertical torsion on the
gearbox command shaft if number 2 or number 3 in the picture would be a little
folded respect original assembly or if the height of the gear lever is been modified)

Ps.2 :before you change the oil, have you noticed if syncros still work
with the anti-friction addictive or if they are more lazy / slow
to syncronize the gears when changing fast?
_________________
Alfa 33

[Brit01]

[Brit01]

Good results guys.

My engine appears to like the 20w/60 so far.

Driving at speed the temperature was about 5 degrees less.

Also I had to reduce the idle rpm by about 250-300 rpm. ( should reduce petrol consumption)

Pressure at 3000 rpm was just over 50 psi even when pushing it really hard.

Idle hot mot much difference, only a few psi more. Maybe the gauge is not so accurate at low pressure, who knows.

Also the geabox oil was good.
_________________
S2 33 1988 1.7 QV
Dellorto DRLA40 (32mm venturi)