One is red and the other isn't. 75/90 NS is a GL5 and MTL is a GL4. For all I know they put red dye in MTL and put more sulpher (a common EP additive) in 75/90. Whatever the difference in chemistry the MTL makes shifting easier in a trans with no mechanical issues.
Sounds good to me, if you recommend it, thats what I'll use MTL for thee Trans, Castrol GTX 20-50 for the engine, Got any good stock tips? Looks like Clear Channel is selling all their TV stations and about 500 of their 1200 radio stations, hope my next owner can put up with me....
Just have to do like me. Make it so it costs more not to employ you. Doesn't really matter how much they don't like you then.
My 328 has been running 20-50 Castrol GTX and I've always heard from mechanics that it is best to keep things as constant as possible. It's not the type as much as the frequency with this car I would think as well. Not sure what to do with the tranny. I've always used redline products in the diffs and tranny's of my BMW's. 75W90 synthetic, Mobil 1 I think, in the tranny currently. I would be interesting to try other options to see if shifting is improved, not that it's a problem. I'd be curious if a redline product would improve cold shifting in the car especially. Jeff
Everybody is talking about Red Line what about Amsoil what's wrong with them, I use them with no problem and not a drop of oil anywhere on my 308 QV, runs smooth, quiet, and stable oil temp at normal op. temp. and stable oil preasure at 85lbs.
Love Amsoil 75W-90 SVG for the tranny. Motor oil, prefer Mobil 1 0W-40. If your hot pressure is 85 lbs at 5 krpm you may want to try using a thinner oil. Also, read AEHASS' papers about oil and visit BITOG discussion board. Seems to me your pressures are very high, meaning your oil is too thick and you could be causing more wear during start up as well.
My 456 GT is 23 years old. I'm in Sydney so the climate is mild all year round. Should I stay with specified oil rating or go to something more suited to an older engine? I use LiquiMoly 10W60 in older BMWs. w
I would still recommend the 10W-40 version. The engine in the F355 was designed and clearanced for a 40 weight oil (14 centiStokes) at 100ºC. In addition the engine materials were chosen so the engine would not self destruct at an oil temperature of 305ºF so long as the oil maintained an HTHS viscosity of 4.2. And finally, the valve train had materials chosen that desire 1100 PPM of ZDDP in order to live a long and healthy life. Those are the 3 numbers you look for in an oil for the F355. 12-15cSt, HTHS > 4.0, and 1100 PPM ZDDP. A long time ago, RedLine had a 5W-30 oil that met every one of these numbers except the HTHS was 3.8 (or 3.9). I tried it it worked good.
Red Line uses a "true" synthetic ester base stock that is quite expensive, not the same as most other "synthetics" which are actually still refined from conventional petroleum oils. I think Motul and Silkolene use a similar base stock chemistry to Red Line, maybe some others do too. Other oils have either natural esters, or much lower levels of the types of esters used in the Red Line. Whether that makes Red Line "better" is wide open to debate, its not like the other oils like big company Mobil or the boutique company Amsoil are lacking anything by using different base stocks and additives. Different chemistry seems to get you to the same ends, for most normal (non industrial) applications. But as a product, I think it is fair to say you do get something for the extra cost of Red Line, being a more costly base stock. You are not paying for marketing, packaging or multi level distribution business models which can be the case in this highly marketing driven industry. The only possible downside I am aware of is the type of esters in Red Line which give it some positive solvent/cleaning properties can be harder on some types of gasket and seal materials ("ester" is kind of a chemistry word for alcohols, and eg. we all know what alcohols in gas can do to hoses and seals if your car is not set up for it in the first instance). Not an issue on modern gasketry, but if you have an old original car, with original gaskets, like pre-1990, you might end up with some leaks where you otherwise might not have had any. But that also probably meant your gaskets/seals were getting heat and age hardened anyway.
I believe, and correct me if I'm wrong. The difference between Gl-4 and GL-5 gear oil is: Gl-5 is designed for extreme pressure in a hypoid type ring and pinion. And GL-4 is for helical type diff. GL-5 is some transmissions might make the synchro rings too slippery to shift good. Use the type of gear oil recommended for your particular drive train!