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Discussion Starter #1
I can't find a definitive capacity for oil in the tunnel case gearbox. Can anyone advise.

Stuart
 

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Tunnel case capacity = 1.35 Kilograms or 3 lbs - page 8 of the Workshop Manual under 'filling up'

Ciao
Greig

Edit: - Thanks for catching that kg's vs liters Uncle
 

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Tunnel case capacity = 1.35 liters or 3 lbs - page 8 of the Workshop Manual under 'filling up'

Ciao
Greig
I will bet that after you scientifically calibrate 1.35 liters and fill the box, the level will be slightly below the filler hole of the box ...testing with your pinky.
 

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Discussion Starter #5
Make sure to use GL 1 or shell Dentax.

Reed

use
Thanks Greig and Reed, using 90 GL1.
Problem with capacity is that I can't get my little finger in the filler hole in the time honoured fashion to check the level and even a dentists mirror is little assistance.
 

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In researching the subject I have two owners manuals. A) earliest manual (clearly 750 tunnel case ONLY manual ) and B) clearly the Split case later model with no mention nor any illustrations of a tunnel-case . Example B) converts the WEIGHT (Kg) of the oil spec to PINTS which is easier to measure from my angle.. EACH SPEC has the tag "ABOUT" as part of the measure. The extrapolation from weight to volume is -----1 Kg = 1.75 pints-- as noted in the later manual.

That given ---BERLINA-- SPRINT--- SPIDER TUNNEL-CASE= 2.36 pints add TI SPLIT CASE= 2.4 pints
SPR/SPI VELOCE TUNNEL-CASE= 2.2 pints add SZ SPLIT CASE= 2.2 pints

ALL REAR AXLES--2.2 PINTS
Steering box-- .4/10 PINTS

I cannot explain the fine hair differences between Veloces and Normales. I think the minor differences are based on engineers dumbing down to EXACTNESS only they could explain It could be for some reason of variations in the different types of the oil but that is only a stab at that.

Hope this helps in the first question. Uncle
 

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Tunnel case capacity = 1.35 liters or 3 lbs - page 8 of the Workshop Manual under 'filling up'

Ciao
Greig
GREG you have a SIGNIFICANT TYPO... IT IS NOT 1.35 LITERS-- IT IS 1.35 Kilograms in your reference.. THAT IS HUGE DIFFERENCE... You just missed the cut for Astronaut training. Even moderators need monitoring... Uncle
 

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Discussion Starter #8
Thanks Uncle,
Is that US pints or Imperial ones.....you can see my original confusion? 1kg of oil is 1.1 litres and thus 1.35 kgs is 1.5 Litres "about". My problem is that the closeness of the synchro hub to the filling hole prevents a little finger dipping into the oil and that is why I wanted a definitive volume.
 

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A bent nylon tie works great for checking hard to get to levels.
 

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ONE pint = .473 Liter 2.4 US (Italian?) Pints (see previous post) x .473 = 1.1352 LITERS So your solution is to buy a one liter can of ale .. drink the contents as I DO with gusto .. Drain the oil.... Open up another can of ale.... drink the contents........install the drain plug ... and open up another can of ale and relight your cigar.... Then you pull the shroud and the bellows off the shifter.. easy in a Giuleitta.. and undo the shifter and remove the sliding plates of the shift tower.....relight the cigar and down the rest of the ale....
Then you rinse out the empty ale container and towel it off..... open up another can and start drinking out of that one... Fill the dry empty one with the correct oil but don't switch the container and start sipping oil..... take a sip of ale and a puff on the cigar ..pour the oil down the shift tower.......Burp...........Then pour two fingers of oil in the can and top off the refill in the tranny... Button it all up and you are good to go for the next 5 to 10 years. Now top it off with two drams of Famous Grouse .. but that goes into your gullet not the tranny... and don't ask how many ounces are in a dram. Uncle
 

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Hi all,

There were little differences recorded between early and later 750 manuals :

8/1957 shop manual says 1,45 kg for Berlina, Spider and Sprints and 1,30 kg for Sprint veloce .
This values are confirmed in an early owners manual.

See the column 'boîte à vitesses' = French for gear box

1617366



Here the 12/1957 shop manual showing 1,35 kg for all models.

1617367


and here the 9/1958 shop manual that says :
1,35 kg for Berlina , TI, Sprint and Spider.
1,25 kg for Sprint veloce and Spider Veloce.

1617368


Could this point to the fact that there would be a difference between the 750 'normale' and Veloce gear box ?
And in that case, wouldn't the volume of the rear cover of the tunnel case gear box with shift lever at the steering wheel be a little bit bigger than the volume of the rear cover for the floor mounted tunnel case gear box ?
Just a thought...



Fwiw, I learned in earlier days that one should fill the gear box untill the fluid starts to drip out of the filler hole. Here I would follow the test with the little pink as Divotandtralee mentioned earlier.
Wouldn't this be the same for the Giulietta gear box?
It would at least solve the 'liter versus kg' problem .


Other thoughts or corrections always appreciated?

Rgds,

Thierry
 

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Gear oil density is about 0.82 kg/l. So divide the spec in kg by 0.82 to get liters.
 

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Remember two separate tunnel case trans. The early ones have the smaller 1st/2nd synchro hubs (30 engaging teeth vs. 36 engaging teeth) obviously the smaller synchro hub implies greater volume in the tunnel box cavity.

Reed
 

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I would stick to VOLUME measures rather than WEIGHT measures.. Alfa was wise enough to insert VOLUME in their latter manuals knowing this.. I never buy my booze by the lb. or Kg... and besides that.. I don't have a pharmacy scale to measure it. The only thing I know that fits the criteria of equal credibility ..weight or volume.... is Bullscccchhhit.. That my friends is a universal measure in whatever units you choose or whatever culture you come from and a ton of it equals a Kg or and ounce no matter what scale you use and it is always too much....
 

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Discussion Starter #16
Making a new termination to the oil filler syringe tube to squeeze into the available space and to make life easier. Following Uncle's good advice as to the Famous Grouse which I will now drink by the 10 gms!
Gubi thank you for your comment on the density of gear oil......I have always used .9 as a working conversion. So between us the capacity is something between 1.5 and 1.65 litres.
 

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My advice was 1.13 liters... If you insist on your levels and assuming your diff is roughly the same spec volume as the tranny by my calculations you can count on oil blowing through the shift tower and blowing past the axle seals in your rear end..ask me how I know. Have fun.
 

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Hi all,

Whatever capacity your gear box has, a final measuring of the fluid level at the filler hole will always be necessary, whether you would refill starting from a complete empty gear box or whether you have to refill partially, and regardless of having the small or the large synchro hub in your gear box as Reed explained rightly earlier.

Wasn't the filler hole mounted intentionally at that specific height for having controle over the minimum and the maximum fluid level ?
The shop manual mentions that the minimum level shouldn't be more than 1cm below the filler hole. Isn't that, in addition of using the correct fluid, the essence for keeping the gear box well-oiled ?

Rgds,

Thierry


1617452
 

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The ultimate "can't stick my finger in the overflow hole" substitute is too simply remove the plug, put a catch pan under the trans, and continue putting in increments of oil until it overflows - then you are certain that the level is correct. This altogether avoids data and conversion correctness.

It sounds like you are, but everyone should be certain to use teh correct type of oil !!! Many "new and improved" oils would be a disaster.
 

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The ultimate "can't stick my finger in the overflow hole" substitute is too simply remove the plug, put a catch pan under the trans, and continue putting in increments of oil until it overflows - then you are certain that the level is correct. This altogether avoids data and conversion correctness.

It sounds like you are, but everyone should be certain to use teh correct type of oil !!! Many "new and improved" oils would be a disaster.
If it was simple as this, don't you think the manual would tell you to administer the refill in this manner? I guarantee using this method for the diff WILL push the oil past the axle seals and it will run out at the axle backing plates after driving the car. Many many rear axle seals have been misdiagnosed as failing seals because the differential was refilled to the point of spilling out of the filler hole. Ask a real tech guy like John Norman or Dean Russell if you don't heed my pedestrian advice. I'm out of here.
 
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