When is the Tranny Full
09-04-2001, 07:31 PM
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When is the Tranny Full
Just changed the transmission oil. 64 oz (2 qts) came out. The Porsche glove compartment manual says 67 oz is the capacity and that's what I put in. Haynes says to test with my finger and that it should be just about at the bottom of the fill plug. What does the Porsche workshop manual say to do. My intuition says that with the vehicle on level ground, fill it until it flows out of the fill plug. Can anyone with a set of the workshop manuals tell me what they say?
Thanks,
Mike
Thanks,
Mike
09-04-2001, 08:38 PM
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From Tech-Session:
For more info Click Here
Good Luck!
Add your new fluid through the top until the level is 6-8mm from the bottom of the hole. You can use your finger to "feel" the level. For cars equipped with an external transmission cooler, the fill level should be a bit higher to allow the cooler to refill completely. DO NOT OVERFILL.
Good Luck!
09-05-2001, 12:38 PM
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The Tech-Session article subsequently states that GL-5 has been recommended by Porsche, but I believe this recommendation has been retracted by the factory. GL-4 is still the recommended lubricant, and quite a few owners have noted that using GL-5 causes the synchros to not work as well.
Greg
Greg
09-05-2001, 01:12 PM
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True, but read on...
If you were to do a survey of actual GL-5 use, I'm quite certain you come up with many more for than against.
I use GL-5 Redline 75W90NS and it feels gooood
YMMV
What about GL-5 vs. GL-4:
The main complaint against GL-5 use in syncro'd trannies is because the chemicals used to provide the extreme pressure protection can be corrosive to synchronizers, which are commonly made of brass or bronze. Here's what the 944 factory manual has this to say: "Filling capacity Approx. 2.0 liters hypoid transmission oil SAE 75W90 to API Class GL5 or MIL-L-2105B, or SAE 80 to API Class GL4 or MIL -L-2105."
Which one is right?:
In the end, it is up to the owner. Though statements of GL-5 use in a syncro'd tranny are somewhat against... history and sales of GL-5 lubricants (like Redline 75W90) continue to be favorable. This is a heavily debated topic, even within the industry. The only things we can assume for sure is: 1. Don't use FM in non-LSD transaxles 2. Don't add FM to make the clutches lock up sooner in LSD equipped cars.
The main complaint against GL-5 use in syncro'd trannies is because the chemicals used to provide the extreme pressure protection can be corrosive to synchronizers, which are commonly made of brass or bronze. Here's what the 944 factory manual has this to say: "Filling capacity Approx. 2.0 liters hypoid transmission oil SAE 75W90 to API Class GL5 or MIL-L-2105B, or SAE 80 to API Class GL4 or MIL -L-2105."
Which one is right?:
In the end, it is up to the owner. Though statements of GL-5 use in a syncro'd tranny are somewhat against... history and sales of GL-5 lubricants (like Redline 75W90) continue to be favorable. This is a heavily debated topic, even within the industry. The only things we can assume for sure is: 1. Don't use FM in non-LSD transaxles 2. Don't add FM to make the clutches lock up sooner in LSD equipped cars.
I use GL-5 Redline 75W90NS and it feels gooood
YMMV
09-05-2001, 01:17 PM
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Hmm. I replaced my gear oil with CASTROL SYNTEC FULL SYNTHETIC Gear Oil
which is a GL-5 oil about 10,000 miles ago.
My shifting is noticeably notchier than it used to be, especially of late. I thought that maybe it was related to my recent clutch master and slave cylinder replacements. Could it be the oil?
Will running a GL-5 oil cause any harm?
PS - seems as if Skip and I posted at the same time. However, I will let the question about the GL-5 causing harm stand.
which is a GL-5 oil about 10,000 miles ago.
My shifting is noticeably notchier than it used to be, especially of late. I thought that maybe it was related to my recent clutch master and slave cylinder replacements. Could it be the oil?
Will running a GL-5 oil cause any harm?
PS - seems as if Skip and I posted at the same time. However, I will let the question about the GL-5 causing harm stand.
09-05-2001, 01:58 PM
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RE: Harm
On one of these threads I posted my experience with Mobil 1 75w-90 GL5 in my LSD gearbox. This even has a promo on the bottle about how good it is for LSDs. I found more metal shavings in the bottom of the case than the last time I changed. With that discovery I went back to the old recommended Shell dino oil.
So yes, I think it could cause harm. Haven't changed out the new oil yet to see what the metal shaving buildup is.
On one of these threads I posted my experience with Mobil 1 75w-90 GL5 in my LSD gearbox. This even has a promo on the bottle about how good it is for LSDs. I found more metal shavings in the bottom of the case than the last time I changed. With that discovery I went back to the old recommended Shell dino oil.
So yes, I think it could cause harm. Haven't changed out the new oil yet to see what the metal shaving buildup is.
09-05-2001, 02:17 PM
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Is it possiable that normal LSD (clutch type) operation would generate some metal shavings (how about track operation)?? I am quite interested in this since I am getting ready to change the transmission oil in my LSD tran.
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09-05-2001, 02:38 PM
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Oh, yes. As far as I know, there are allways a few shavings from LSD. Because it is under greater stress as you force the wheels in different radii turns, I was told. I was just noting that with Mobil 1 I noticed more than ever before.
This was just the 'ole finger test. What caused the increase, I'm not sure. Just got uncomfortable enough with all the talk on how some synthetics were bad on gearboxes and then I go find "extra" metal shavings.
The other thing I noticed is that the transmission made more of the "loose marbles" sound with Mobil 1. That is the sound you get when sitting out of gear with the clutch out/engaged and driving the shaft.
It was all enough to make me stop using it for the current change.
This was just the 'ole finger test. What caused the increase, I'm not sure. Just got uncomfortable enough with all the talk on how some synthetics were bad on gearboxes and then I go find "extra" metal shavings.
The other thing I noticed is that the transmission made more of the "loose marbles" sound with Mobil 1. That is the sound you get when sitting out of gear with the clutch out/engaged and driving the shaft.
It was all enough to make me stop using it for the current change.
09-05-2001, 05:55 PM
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If you call redline on the telephone, they tell you not to use thier GL5 rated oils in 944s because they will ruin your transmission. I use Redline MTL, which is a GL4 rated product.
09-05-2001, 08:00 PM
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Fellas,
Great posts. Thanks very much. A special thanks to Skip for your usual excellent assistance. The info referring to the optional oil cooler was helpful as that's what I have. I put in Mobil 1 (GL-5 I believe) on the recommendation of a Porsche service tech. I'll make some inquiries this weekend (Zippo U.S. Vintage Grand Prix at Watkins Glen) with some 944 zealots regarding the GL-4 or GL-5 issue.
Thanks again,
Mike
Great posts. Thanks very much. A special thanks to Skip for your usual excellent assistance. The info referring to the optional oil cooler was helpful as that's what I have. I put in Mobil 1 (GL-5 I believe) on the recommendation of a Porsche service tech. I'll make some inquiries this weekend (Zippo U.S. Vintage Grand Prix at Watkins Glen) with some 944 zealots regarding the GL-4 or GL-5 issue.
Thanks again,
Mike
09-05-2001, 08:15 PM
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Originally posted by Cobbs:
<STRONG>Yeah, what makes the "loose marbles" sound anyway?</STRONG>
<STRONG>Yeah, what makes the "loose marbles" sound anyway?</STRONG>
I refer to it as the "box-o-rox", but that's no matter... Technically, the deceleration noise is caused by GTMR (Gear-Tooth-Mesh-Rate)... many of them, from the diff to the individual gears themselves... harmonics and maybe even some modulation thereof. The reason it's so loud on the 944: the entire drivetrain is one big unit... the transaxle, driveshaft (torque tube), and engine are all one big sound transmission device. "Well, that's about all I have to say about that..."
EDIT: Oops, just read what the original "loose marbles" sound was describing... and my description is NOT for that noise. Mine is for in gear deceleration. That "loose marbles" description sounds more like a failing throwout bearing in the clutch. May want to have that checked out, or maybe it is coming from the tranny... while disengaged?
