Oil quality & heat cycles

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I've read that motor oil/gearbox oil may not be working at optimal levels until it's gotten hot & cooled a few times.. eg certain additives not coming "to life" until after a few heat cycles. Is this accurate? Thx!
 
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The anti-wear compound ZDDP (Zinc Dialkyl-Dithiophosphate) needs to get up to high temperature in order to be activated and deposit its protective layer onto wear surfaces. There are different types of ZDDP that activate at lower temperatures, but how can you know which is in your oil? So you take it easy on the first few runs after a rebuild until the tribofilm has had time to form.
 

BLKGTTDI

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Thanks for your reply. My oil is VW G-052-171-A2 Viscosity at 40C 31.2 cSt Viscosity at 100C 6.5 cSt Silicon 7 Boron 140 Calcium 7 Barium 0 Phosphorus 297 Zinc 1 Molybdenum 220 Do any of the above ingredients require heat cycles or heat in anyway to perform optimally?
 
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That is an oil for a VW TDI? It has very low viscosity, and with 1 ppm of Zinc, it doesn't appear to have any ZDDP content.
 

BLKGTTDI

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Originally Posted By: A_Harman
That is an oil for a VW TDI? It has very low viscosity, and with 1 ppm of Zinc, it doesn't appear to have any ZDDP content.
Correct its for a 6 speed Mk5 GT TDI. I have a recon'd gearbox, I changed out their oil for the VW stuff but doesn't seem to be any difference in shift feel yet. VW stuff has only been in a few days and I've only done short local trips. I wondered if over time & longer drives the oil may "improve"
 
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Oh, I see. It's for the gearbox, not the engine. You did say gearbox in your original post, but I wasn't sure. I wouldn't expect the shift feel to improve over time. Why do you have a recon gearbox? Did the first one fail? What lubricant does the rebuilder recommend?
 

BLKGTTDI

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Originally Posted By: A_Harman
Oh, I see. It's for the gearbox, not the engine. You did say gearbox in your original post, but I wasn't sure. I wouldn't expect the shift feel to improve over time. Why do you have a recon gearbox? Did the first one fail? What lubricant does the rebuilder recommend?
The first one had serious 1st to 2nd gearshift issues. Consistantly notchy & gratey. Had a new flywheel & clutch but I still had an issue with a poorer quality 1st to 2nd gear change which was made worse if the change was made while turning right. Out of the option of repair or recon I went recon. However, even now with the recon'd box I still get the odd notchy 1st to 2nd gear shift if I shift while turning right! I've taken the car to two garages and neither of them think it's a fault with the gearbox. One mechanic explained that the g-force of turning could close slightly the clutch/flywheel space and that even a tiny percentage of a milimetre of wear to the flywheel & it's nackered. He kinda implied it's just "one of those things" I just kinda hope that after a while with the new gearbox oil it'll get better. I think the recon company said 75w80 or 75w90 but I've put the correct VW specified oil in it as stated for 02Q 6 speed which is actually quite thin! I had hoped the thinness would give me better gear changes.
 

MolaKule

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This MTF has the new multi-functional phosphate ester and is one of the Low viscosity (LV) MTFs, about a 70 grade gear oil. With this stuff you don't need ZDDP. Definately not a 75W80 or 75W85.
 
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BLKGTTDI

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Originally Posted By: MolaKule
This MTF has the new multi-functional phosphate ester and is one of the Low viscosity (LV) MTFs, about a 70 grade gear oil. With this stuff you don't need ZDDP. Definately not a 75W80 or 75W85.
Thank you for this information another forum also clarified this that G052 171 A2 is thinner than VW / AUDI specify. Would there be any bennifit of adding some ZDDP into the gear oil as I have little in the oil as it is? My gear changes are still a little notchy I feel thay could be better. My understanding is that ZDDP coats the metal with a hard protective coating? Many thanks.
 
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Originally Posted By: MolaKule
This MTF has the new multi-functional phosphate ester and is one of the Low viscosity (LV) MTFs, about a 70 grade gear oil. With this stuff you don't need ZDDP. Definately not a 75W80 or 75W85.
Is also of Low flamability like the phosfate ester hydraulic version Skydrol?
 

MolaKule

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ZDDP dos not "coat" anything. What it forms is a plastic film of ferrous-sulfate-phosphate at the surfaces. The ZDDP is not needed with this MTF and it will not help shifting. This gear lube is more like a low viscosity (LV) ATF. There are plenty of dedicated 70W80's and 75W85's with higher levels of Anti-wear additive that you might try in lieu of this stuff. Purchasing an LV MTF and then attempting to dope it with aftermarket goop doesn't really make a lot sense.
 
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BLKGTTDI

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Originally Posted By: MolaKule
There are plenty of dedicated 70W80's and 75W85's with higher levels of Anti-wear additive that you might try in lieu of this stuff. Purchasing an LV MTF and then attempting to dope it with aftermarket goop doesn't really make a lot sense.
Thanks for the information. May I ask for a suggestion of a similar viscosity MTF viscosity at 40C 31.2 cSt, viscosity at 100C 6.5 cSt that does have better anti-wear & friction reducers? Many thanks.
 
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my poor shifting O2J 5 spd in a 2001 jetta barely shifted into 5th @ 95,000 miles + going into 2nd was never good. i put in Redline MT-90, shifting was slightly better right off but by 5,000 miles it worked decently! also put it in my 2001 TT with a 6 spd O2M box for a nice improvement. prior to that i changed the OE to amsoil 75-90 at 50,000 with no improvement as it continued to degrade, Redline gets my $$$$
 
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