to no avail in the fluids/lubricants forums, i hope to some feedback here in the 4th gen forum, hehe.

--> i heard that the import crowd (not just nissans) have been putting in GM Transmission Fluid designed for Corvettes in their transmissions, because supposedly it makes the tranny run ==> quieter & smoother <==

anyone have a say in this?

 

I have a C5 and only use the GM transmission fluid. Though many people may use the GM fluid in their imports, I wouldn't recommend using it. Use the fluid that was intended for your car. Better safe than sorry. Check the viscosity of both fluids before jumping into a fluid switch.

 

You can try it, but I don't think it matters much. It's not API GL rated, so it's hard to compare it with our tranny fluids.

http://www.stealth316.com/2-pennzoil-synchromesh.htm

Dave

 

nothing beats redline mt90

 

If its GM synchromesh it will be fine. I've got it in my turbo car and I don't really notice any difference, it's what the trans shop I work at recommends people put in their DSMs and Evos and all transmissions with brass synchros or significant amounts of other yellow metals, which is to say most import transmissions really.

 

I am using GM synchromesh too. I had smoother shifting than MTL90. It says in the mfg material that it is yellow metal safe--that is good enough for me. Me likey...

If you have more than one car or want a lifetime supply for your max, the 5 gal bucket is a good value.
http://shop.store.yahoo.com/oilstore/pensyn5gal.html

 

C5s used the GM synchromesh.

 

I take it were talking manual trans fluid here.

 

yes M/T fluid

 

Amsoil > Redline.

 

what makes amsoil better than redline? or just your opinion

 

Always opinion.

The differences between them are hard to measure, and if you could they would depend on many things. Plus, very rarely does someone go from a properly-filled gearbox of new Amsoil to a properly-filled gearbox of new Redline so they can make a useful comparison. IME, 98% of the difference noticed by the user is because there was something 'wrong' with the old oil (underfilled, worn out, dirty), not because the new oil is significantly superior.

Dave

 

Wear protection is the main advantage.

 

Actually you're wrong. My decision is not based on opinion. Iwannabmw is regarded as one of the more knowledgeable guys when it comes to lubricants. This is what he had to say in response to my question back when i still had my old username.

http://forums.maxima.org/showpost.ph...0&postcount=14
Now before you go off and say that none very few of us drive in race conditions, those race conditions are just an extrapolated version of daily driving over time. I'll take the added protection, thanks. I'm not saying Redline is no good, but some people have actually switched from Redline to Amsoil and found the shifting action to be smoother. Whether that was because of the Redline fluid being old and broken down or not, the point is that Amsoil offers similar shifting smoothness with superior wear protection, is cheaper, and stands behind their product with a warranty. Can't go wrong.


FYI, i'm running MT-90 and will be switching to Amsoil soon. I'll let you know what my own findings are.

 

While it's good info to see that the Amsoil showed less evidence of wear (and I'm happy to see you have based this on some form of experience), I have to wonder what parts were wearing. There are tradeoffs here - synchros grab the gears better (reducing the loads on the clutch sleeve teeth) when there is less 'protection' because the synchro cones apply better friction to the spinning gear. A less 'protective' oil will allow the synchros to bite and grip better, allowing quicker gearshifts, but the synchro friction faces themselves will usually wear faster. Even this will vary as the synchros get worn down - so the oil that performs best in one tranny may not apply well to one that has much newer synchros.

As for relating race use to street use, I don't think that is a generally true comparison. While the wear on the gear faces is reasonably similar, the performance of the synchros is not. Trying to shift fast is a whole different loading situation than shifting at a pace where you can feel the car shift smoothly into the gear.

Anyway, I think we're mostly on the same page here - good oil is good oil. My opinion is that switching from one brand to the next is mostly a waste of money. For someone who wants to change brands, I suggest they wait until the current oil has seen 60k, or some other service reason.

Dave

 

Well according to redline the reason that MT-90 offers such good synchro engagement is due to the coefficient of friction of the fluid, not necessarily because it's a "thin and unprotective" fluid. The Amsoil and MT-90 share the same viscosity, so it's the additives within the fluid that makes a difference. This is why motor oil is dismissed as an appropriate gear lubricant; not because it's too thin, but because it's too slippery to allow the synchos to mesh properly. So it's still up in the air as why exactly Amsoil offers superior wear protection.

I can agree with that. But at the same time, i think it's safe to say that a gear oil that protects better in high temp/high load situations will protect better as well in everyday driving over a long period of time, even if it's not by as wide a margin.

Agreed. There isn't enough evidence to suggest that everyone that has MT-90 in their gearboxes right now should rush out and get Amsoil, but it might be worth it when the MT-90 starts to break down. After all, it IS cheaper.

 

Fluids by definition do not have any coefficient of friction. Redline's site says "balanced slipperiness provides a perfect coefficient of friction" - I think in a technically poor language, they are saying their oil has the proper amount of additives for GL-4 gearboxes, so that the synchros will have the proper coefficient of friction when wetted. (Technically, this coefficient of friction applies only when you rub the brass synchro to the steel gear cone while wetted with that oil - so it's not really a property of the oil). Which, if you give them that latitude, I agree with.

Amsoil has several gear lubes, but the MTG is the only one that is GL-4. The Series 2000 that was compared isn't even a GL-rated oil - it's simple gear oil. It says it's designed for "Extreme pressure additives provide extra wear protection", which would 1) reduce the grab of the synchros which reduces the visible wear on them and 2) reduce the function of the synchros which increases the chance of gear grinds and harsher engagement. So that Series 2000 oil should have much more lubrication than any GL-4 or even any GL-5 gear oil. It might reduce wear on the cone surface of the synchro, but it could cause heavier wear on the synchro teeth, clutch sleeve teeth, and gear teeth. Having rebuilt a couple trannys myself, I would far prefer to be buying synchros than gears and clutch sleeves. While better lubrication helps in most gearbox applications, in synchromesh trannys there will always be a tradeoff. Plus you can't tell if it has any ingredients which might attack the copper-alloyed parts. These two reasons are why I would not run a Series 2000 in any synchromesh transmission, unless I had good proof that it was not causing extra wear on the hard parts, and it won't chemically attack the synchros.

One thing has me wondering: The only lube with "Series 2000" in the name on Amsoil's site is chain lube. But it doesn't sound the same as the "Series 2000 75w-90" mentioned here. So if it is different, you can disregard some of that last paragraph.

Now Amsoil's AGT and MTG gear lubes (both GL-4s) - those I will be considering on my next fillup. But I'll have to give up my Neo 75w-90HD first. If gear lubes were an easy comparison, we wouldn't be having these discussions

Dave

 

Understood. I just worded it incorrectly.

I guess the "less wear" thing won't be definitive until the exact parts that wore more quickly are identified.
Series 2000 has been discontinued and replaced by MTG in their lineup. This is what i'll be trying next.

 

Redline used that wording first, not your mistake It is possible that in the tribology field, that when the materials are assumed, it is technically correct to say it that way.

Thank you - that explains a lot.

Dave