kozmikkroozer Posted September 17, 2011 Report Share Posted September 17, 2011 I'm putting in a clutch/flywheel today and am having a hard time finding the correct tranny oil. I would prefer Diaqueen or Redline MT-90 but no one carries it locally. I would like to get this together today and the only local trans oils I could find where mostly GL5 spec.I'm hesitant to use GL5 as there are so many differing opinions as to the corrosive ingredients in GL5 that may cause the soft metals in our older transmissions to corrode. I did find Royal Purple Max Gear 75w-90 which says it meets both the GL4 and GL5 specs.Quote "The noncorrosive nature of Max-Gear provides excellent results in applications for both GL-4 and GL-5 fluids"After searching numerous forums regarding this topic there doesn't seem to be a definitive answer out there.I've put a call into Royal Purple and they are going to get back to me but does anyone have experience with this particular oil in our cars? Link to comment Share on other sites More sharing options...
JohnnyWadd Posted September 17, 2011 Report Share Posted September 17, 2011 http://www.synthetic-oil-tech.com/Gear%20Lube%20White%20Paper.pdf Link to comment Share on other sites More sharing options...
Killtodie Posted September 17, 2011 Report Share Posted September 17, 2011 I have been using gear oil but was recently told that its too slippery and not the best oil to use for our syncros. But I'm not sure about that though. Link to comment Share on other sites More sharing options...
Komeuppance Posted September 17, 2011 Report Share Posted September 17, 2011 Here's some info, click the arrow to read the rest of the thread.It was found that yellow metals were damaged by high sulfur content, but at 250F and above. Modern GL5's use inactive or buffered sulfur and will not damage synchros. Many manufacturers are issuing TSB's that spec GL5(vs previous GL4 spec) because GL4 is becoming less and less available (and probably due to the high volume of inquiries on the matter haha). Each classification uses different amounts of EP additive (Extreme Pressure additive), a GL4 will use about half the amount of EP additive that a GL5. EP additives contain the elements(sulfur) found to be corrosive to yellow metals. GL4 and GL5 have different friction modifiers depending on their designed use. A GL4 will be designed for optimum syncromesh engagement. With that said, a modern GL5 will not destroy your transmission, but it may not be optimal for shifting smoothness.-Robert Link to comment Share on other sites More sharing options...
kozmikkroozer Posted September 17, 2011 Author Report Share Posted September 17, 2011 Amsoil appears to be the best oil looking at Johnny's post but when you look up the Starion on the Amsoil website they don't recommend any of their oils.I'm not feeling positive about that self incriminating bit of info.http://www.amsoil.co...BISHI+STARION+NDiaqueen is 100 bucks and comes in a 4 liter container, I only need 2.5 ...so after careful consideration it looks like the best choice is Redline MT90 sold for 13.49 per quart and ships for free from Amazon. Link to comment Share on other sites More sharing options...
slowquest Posted September 17, 2011 Report Share Posted September 17, 2011 Autozone carries a GL4 fluid, but I can't recall the exact name at this point. Link to comment Share on other sites More sharing options...
Starfighterpilot Posted September 19, 2011 Report Share Posted September 19, 2011 (edited) I used Valvoline GL-4 85W-90 oil in my 5 speed tranny since her first tranny oil change back in '90. The tranny has Always shifted SMOOTHLY between gears. I changed the tranny oil every 2 years regardless of mileage. The tranny lasted until 12/09 with about 375K miles on it. The reason it failed was the tail shaft oil seal gave up the ghost on the way back to Atlanta, during one of my LONG trips with the Old Broad and I did not notice the leakage. Consequently, the upper tranny shaft bearings failed due to lack of oil. When the tranny was torn down for rebuilding, the gears and syncro's showed very little evidence of wear, I was there during the tear down and witnessed the as found conditions in the tranny rebuild shop. So the gears and syncro's were not replaced cuz I PREFER using OEM mistsu parts and the gears and sycros looked like new, rather than replacing the syncros which were included in the after market NAPA tranny rebuild kit. The rebuilt tranny was filled with Valvoline 85W-90 tranny/gear oil. Since the tranny was rebuilt, I have put on about another 33K miles on the Old Broad. Some fellow Starquesters, that have recently driven her, have commented that my 5 speed tranny shifts MUCH smoother than their rebuilt/unrebuilt trannys with a hell of a lot less miles than my Old Broad has. BTW - The FSM states to use the GL-4 tranny/gear oil. So my recommendation is use the Valvoline GL-4 85W-90 weight tranny/gear oil. Don't spend excessive money on the over kill high priced synthetics. Use the saved money to buy enough GL-4 oil for a couple of more tranny oil changes. For What It's Worth. KEN Edited September 19, 2011 by Starfighterpilot Link to comment Share on other sites More sharing options...
Caliber308 Posted September 20, 2011 Report Share Posted September 20, 2011 Not another Manual Transmission Gear oil question Bill Link to comment Share on other sites More sharing options...
slowquest Posted September 20, 2011 Report Share Posted September 20, 2011 Not another Manual Transmission Gear oil question Bill http://discoveringalcoholic.com/wp-content/uploads/images/deadhorsebeating.gif Link to comment Share on other sites More sharing options...
JohnnyWadd Posted September 20, 2011 Report Share Posted September 20, 2011 Amsoil appears to be the best oil looking at Johnny's post but when you look up the Starion on the Amsoil website they don't recommend any of their oils.I'm not feeling positive about that self incriminating bit of info.http://www.amsoil.co...BISHI+STARION+NDiaqueen is 100 bucks and comes in a 4 liter container, I only need 2.5 ...so after careful consideration it looks like the best choice is Redline MT90 sold for 13.49 per quart and ships for free from Amazon. I noticed too. I dont see why amsoil would not work. I think its a oversight on there part. Link to comment Share on other sites More sharing options...
Caliber308 Posted September 21, 2011 Report Share Posted September 21, 2011 (edited) Guys, You don't have to use Diaqueen in your Manual Transmission, that is recommended for the Limited Slip Differential. (Rear End) As far as the Manual Transmission goes. Here is a quote from the 1987 FSM on what to use: 1987 Starion FSM Volume no.1, Section 0-6 Lubrication and Maintenance- Recommended Lubricants. Manual Transmission- API classification GL-4 or "higher". I personally have used GL-5 80/90wt Gear Oil in my ESI-R Manual Trans. for 22 years with no ill effects.Replaced the Clutch twice: Once because it was worn, the second time was for a Engine rebuild. Never had to replace the gears !!! I don't know how many times myself and others have posted this answer:It is O.K. to use GL-5 Gear Oil in your Manual Transmission. But here it is again.....IT IS O.K. TO USE GL-5 GEAR OIL IN YOUR MANUAL TRANSMISSION. I go off what works, be it GL-4, or GL-5 for me. Either one will do. Just make sure you install the proper weight for your climate. Synthetics??? Yea, if you don't like changing the Manual Transmission Gear Oil every 30,000 miles. Other than that......They are a waste of money. Bill Edited September 21, 2011 by Caliber308 Link to comment Share on other sites More sharing options...
Dred_85.5_TSI Posted September 21, 2011 Report Share Posted September 21, 2011 I believe I used a Penzoil GM synchromesh gear oil. I've had good luck with it, I just need to slow down my shifting to let the clutch and synchros work before I try to shift.Here:http://www.autozone....ier=265000_0_0_ Link to comment Share on other sites More sharing options...
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