Manual Transmission Fluid?
01-15-2013, 10:32 PM
#32
Instructor
Thread Starter
Here's why your tech is telling you your LSD is toast:
https://rennlist.com/forums/997-gt2-...sd-buster.html
The 2004 996 Anniversary vehicles got the same LSD as the 2004 GT3s, so they actually have decent ramps in them. All you need to do to make it a fully functional LSD is reclutch it...
https://rennlist.com/forums/997-gt2-...sd-buster.html
The 2004 996 Anniversary vehicles got the same LSD as the 2004 GT3s, so they actually have decent ramps in them. All you need to do to make it a fully functional LSD is reclutch it...
The big let down about that thread is when Bernie says there's a big difference in the gear oil you use, and then didn't say which ones were good.
01-16-2013, 01:17 PM
#34
Nordschleife Master
John,
You should know by now that I don't make gear oil recommendations. There are 2 dozen good gear oils out there with very little performance or protection difference from one oil to the other.
I have two standard comments on gear oil. The best gear oil is the one that you change frequently, and I mean way way more frequently than Porsche's ridiculous service intervals.
Number two is there is only one oil that I tell people to never ever use, that is Redline Shockproof. The stuff was made for rear ends. That's the only thing it is good for. Don't put it into a transaxle where you've got gears and synchros in addition to a ring and pinion.
You should know by now that I don't make gear oil recommendations. There are 2 dozen good gear oils out there with very little performance or protection difference from one oil to the other.
I have two standard comments on gear oil. The best gear oil is the one that you change frequently, and I mean way way more frequently than Porsche's ridiculous service intervals.
Number two is there is only one oil that I tell people to never ever use, that is Redline Shockproof. The stuff was made for rear ends. That's the only thing it is good for. Don't put it into a transaxle where you've got gears and synchros in addition to a ring and pinion.
01-16-2013, 09:49 PM
#36
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John,
You should know by now that I don't make gear oil recommendations. There are 2 dozen good gear oils out there with very little performance or protection difference from one oil to the other.
I have two standard comments on gear oil. The best gear oil is the one that you change frequently, and I mean way way more frequently than Porsche's ridiculous service intervals.
Number two is there is only one oil that I tell people to never ever use, that is Redline Shockproof. The stuff was made for rear ends. That's the only thing it is good for. Don't put it into a transaxle where you've got gears and synchros in addition to a ring and pinion.
You should know by now that I don't make gear oil recommendations. There are 2 dozen good gear oils out there with very little performance or protection difference from one oil to the other.
I have two standard comments on gear oil. The best gear oil is the one that you change frequently, and I mean way way more frequently than Porsche's ridiculous service intervals.
Number two is there is only one oil that I tell people to never ever use, that is Redline Shockproof. The stuff was made for rear ends. That's the only thing it is good for. Don't put it into a transaxle where you've got gears and synchros in addition to a ring and pinion.
01-22-2013, 12:36 AM
#37
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I can say from personal experience;
1) Do not use Amsoil 75W-90 Severe Gear due to inability to engage gears without double clutching while cold and very notchy shifting when hot (and based on their lack of customer support, I will avoid them altogether going forward for all my cars and bikes, as will my bud), and
2) Do not bother with OTC Mobil1 75W-90 (much better than #1, but not OEM balanced feel with still some clunking between gears in lower revs that OEM fluid did not display).
I am now loading my 3rd and last aftermarket try with this before I surrender to OEM fluid fill (Mobilube PTX I believe). Based on GT3 owner bud recommendation and other research I will use Mobil Delvac 75W-90:
http://www.lufteknic.com/Merchant2/m...ode=lubricants
no association, just where I bought it from (although head tech took 15 minutes to talk me through lots of P-car questions and share his knowledge... clearly an enthusiast and teacher so it was easy decision to patronize them!):
I'll report back with my findings so anyone can learn from my 3 experiments.
note: Tech I talked to stated the LSD in my 40th is likely to have turned into an open diff after 10k miles with aggressive driving since clutch packs are known to be high wear items in the P-car LSD... take it for what it's worth.
1) Do not use Amsoil 75W-90 Severe Gear due to inability to engage gears without double clutching while cold and very notchy shifting when hot (and based on their lack of customer support, I will avoid them altogether going forward for all my cars and bikes, as will my bud), and
2) Do not bother with OTC Mobil1 75W-90 (much better than #1, but not OEM balanced feel with still some clunking between gears in lower revs that OEM fluid did not display).
I am now loading my 3rd and last aftermarket try with this before I surrender to OEM fluid fill (Mobilube PTX I believe). Based on GT3 owner bud recommendation and other research I will use Mobil Delvac 75W-90:
http://www.lufteknic.com/Merchant2/m...ode=lubricants
no association, just where I bought it from (although head tech took 15 minutes to talk me through lots of P-car questions and share his knowledge... clearly an enthusiast and teacher so it was easy decision to patronize them!):
I'll report back with my findings so anyone can learn from my 3 experiments.
note: Tech I talked to stated the LSD in my 40th is likely to have turned into an open diff after 10k miles with aggressive driving since clutch packs are known to be high wear items in the P-car LSD... take it for what it's worth.
01-23-2013, 08:03 PM
#39
2) Do not bother with OTC Mobil1 75W-90 (much better than #1, but not OEM balanced feel with still some clunking between gears in lower revs that OEM fluid did not display).
I am now loading my 3rd and last aftermarket try with this before I surrender to OEM fluid fill (Mobilube PTX I believe). Based on GT3 owner bud recommendation and other research I will use Mobil Delvac 75W-90:
I am now loading my 3rd and last aftermarket try with this before I surrender to OEM fluid fill (Mobilube PTX I believe). Based on GT3 owner bud recommendation and other research I will use Mobil Delvac 75W-90:
I used Lucas gear oil with LSD additive in it.
Imre, my Dad loves this stuff for his tractors and equipment. What is your thoughts on it?
01-24-2013, 12:56 AM
#40
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[QUOTE=KrazyK;10167218]Viper, do you really feel this much difference bewteen these two? Mine only feels a little odd when cold. If your sure, I think I will order some too. I love to drain the fluids in my car and examine them. Im thinking about running a pipeline from the refinery to my shop.
Ha, that pipeline will cut back on cost per fill. I am so pleased that I bought an extra gallon (ok I bought two at the same time hoping it was the one, but now I'm glad I did). I will say that I remember draining the OEM fluid and it had a unique pine tree smell and greenish tinge, both beyond standard GL5... the Delvac had this same smell and tinge going in when the others did not. I know its anecdotal, but I trust my nose and that corroborated what the Tech told me... this is the Mobilube PTX OEM fill rebranded/rebottled. I'm inclined to believe it now.
The most important thing is the stock performance is back as I remember... very decent shifting when cold and slick notch-free shifting when warm... I've now stopped kicking myself for dumping the OEM fill early... ha.
The difference between Delvac and the others is night and day, definitely go with the Delvac...Good luck!
Ha, that pipeline will cut back on cost per fill. I am so pleased that I bought an extra gallon (ok I bought two at the same time hoping it was the one, but now I'm glad I did). I will say that I remember draining the OEM fluid and it had a unique pine tree smell and greenish tinge, both beyond standard GL5... the Delvac had this same smell and tinge going in when the others did not. I know its anecdotal, but I trust my nose and that corroborated what the Tech told me... this is the Mobilube PTX OEM fill rebranded/rebottled. I'm inclined to believe it now.
The most important thing is the stock performance is back as I remember... very decent shifting when cold and slick notch-free shifting when warm... I've now stopped kicking myself for dumping the OEM fill early... ha.
The difference between Delvac and the others is night and day, definitely go with the Delvac...Good luck!
01-26-2013, 10:58 AM
#41
All lubricants are sorted by Viscosity Index from highest to lowest.
Lubricants #: 2 & 3 in grey are Porsche approved.
All data except Viscosity at 0*C came from lubricant respective published data sheets.
All viscosities at 0*C were calculated using Mr. Widman’s chart and should be considered as approximate as most lubricants do not behave as Newtonian fluids.
Many thanks to Richard Widman.
http://www.widman.biz/English/Calculators/Graph.html
Mobilube PTX had viscosity at 0*C published by Mobil at 590 cSt and marked as Actual in the table above.
Below is the note from Mobilube PTX Data Sheet:
“The combination of synthetic base fluid technology and special high performance additives have been carefully formulated to meet the low temperature fluidity requirements of Porsche ( Kinematic Viscosity at 0ºC of < 600 cSt)”
Enjoy,
=L=
01-27-2013, 01:35 PM
#42
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Cool, empirical data is great! I wonder what the stats for the two other fluids I tried and significantly disliked are... Amsoil 75w-90 Severe Gear and OTC Mobil1 75w-90... Feel free to add these to your chart and re-publish all in one spreadsheet?
@40*C, cSt @100*C, cSt VSI @0*C, cSt
Mobil1 75W-90 99 15.2 142 937.6
Amsoil 75W-90 87.6 13.9 162 801
Amsoil 75W-90 SG 114.7 16.9 161 1135
Based on this my near freezing cold weather experience I should dislike the Delvac at least as much, if not more than the Amsoil SG... clearly there is more to it than just viscosity... seems easier to engage gears than even the Mobil 1 which has lower viscosity at comparable temps... hmm.
If I can find a P-car approved fluid for less than $40 a liter I'd try it...
@40*C, cSt @100*C, cSt VSI @0*C, cSt
Mobil1 75W-90 99 15.2 142 937.6
Amsoil 75W-90 87.6 13.9 162 801
Amsoil 75W-90 SG 114.7 16.9 161 1135
Based on this my near freezing cold weather experience I should dislike the Delvac at least as much, if not more than the Amsoil SG... clearly there is more to it than just viscosity... seems easier to engage gears than even the Mobil 1 which has lower viscosity at comparable temps... hmm.
If I can find a P-car approved fluid for less than $40 a liter I'd try it...
Last edited by Viper6; 01-27-2013 at 02:18 PM.
