I posted some information not too long ago that you guys may want to look over, may clear some things up on this issue, w
http://forums.focaljet.com/shift/551814-focus-manual-transmission-amsoil.htmlhich you can read below here as well. I originally posted this in the Shift It section.
Ive been getting some questions regarding the correct Amsoil fluid to use in the Focus 5-spd and SVT 6-spd transmission. I thought that I would make a post here about this so more poeple could see the information. Perhaps we can keep it near the top for a short time so that we get good coverage.
Product and Recommendation History
Amsoil is VERY good about staying current on product recommendations. I have come to trust what they say needs to be used. I have seen instances where they recommended a product or viscosity different from what the dealer and manual recommended only later to have a TSB from the dealer show a recommendation for what Amsoil already said needed to be use.
There are three manual transmissions out there for the Focus that I am aware of. The IB5 (SPI Focus), the MTX-75 5-spd (Zetec, etc) and the MT-265 6-spd (SVT). Amsoil has always keep the group recommendation for them the same. That is to say, what lubricant it recommended for one was recommended for all.
I remember a few years ago a customer came to me with a Focus sedan with the MTX75. He had done some research and was ready to buy, but wasnt sure what the 5-spd needed for fluid. He had called the dealer and they told him to use Automatic Transmission Fluid (which some Ford manual transmissions use). Amsoil said 75W-90 should be used. He didnt want to put himself in a position with getting denied warranty service so placed an order for the Amsoil synthetic automatic transmission fluid.
A couple months later he got back in touch with me and said his transmission was getting very 'notchy' and difficult to shift. I told him to try the Amsoil recommended gear lube. He got that installed and has been a happy camper since.
The European 5W-40 Motor oil came in 2004 and Amsoil changed their recommendation from the 75W-90 to the 5W-40. If I remember correctly (I couldnt find the documentation to prove it) Amsoil recommended the Series 3000 5W-30 Diesel oil for a short time until the 5W-40 came on the market.
The Manual Synchromesh Transmission Fluid came on the market in 2005. Now remember Amsoil changed their recommendation from the 75W-90 to the 5W-40 as soon as that fluid was available. Incidently a 75W-90 gear lube and 5W-40 are close to the same viscosity. However, even when the Synchromesh fluid came on the market, Amsoils recommendation for the Focus manual transmissions never changed and have not to this day.
The differences that count
I think it worth pointing out a couple of things or differences between the 5W-30 Synchromesh and the European 5W-40.
First, the Synchromesh fluid is intended in applications, manual transmissions and transaxles where non-extreme pressure fluids are used. What does that mean? It means its a good lubricant where there is not enough load to pose a risk of 'squishing' the fluid out of the boundry layer (between the metal surfaces). In other words, Amsoil Synchromesh probably doesnt have any EP (Extreme Pressure) Additives.
Why is this important? Because the Amsoil Series 2000 75W-90 gear lube was Amsoils top of the line Extreme Pressure gear lube, meaning it was specifically designed to handle such situations. Motor oils also have EP additives in them as well.
What does this mean to you? It means that the possibility exists that in certain high load conditions (think WOT) its possible to force the Synchromesh fluid from between the metal surfaces and get metal to metal contact, however brief it may be, any such contact is not good and accelerates wear.
Secondly, the Amsoil Synchromesh fluid has a Kinematic Viscosity of 9.6 @ 100* C, the European 5W-40 Kinematic Viscosity is 13.7. Remember that customer of mine that use the Automatic Transmission Fluid? Well a Viscosity of 9.6 is just barely and I mean just barely a 30 weight fluid. 9.3 is the cut off for 20 Weight. Want to guess what weight range ATF falls in? Yep, in the 20 Weight range. Transmission fluid is a little thinner, but not by some huge margin.
The 5W-40 viscosity of 13.7 puts it near the middle of the 40 Weight range. The current 75W-90 gear lubes from Amsoil have a Viscosity of 14.7 to about 16.5 which puts them also in the range of 40 Weight to the very low side of 50 Weight.
Lubrication related failure and warranty
Lastly of major significance in this is your warranty from Amsoil. If you choose to use the Synchromesh 5W-30 and have a failure directly related to the lubrication, you wil have no coverage under the Amsoil warranty because Amsoil recommends use of the European 5W-40 fluid.
Now I am aware some of you have been using the Synchromesh without any troubles, at least none that anyone is reporting. It may be that the Synchromesh fluid will work or do a good enough job. But when has anyone settled for 'Good Enough' when it comes to a car they love? If Amsoil says the 5W-40 is what should be used then I trust it is the best available that can be used.
Closing
Yeah, I know, long winded, but I wanted to get the info out there with as much detail as I could. I hope this has been helpful to someone. I also hope it clears up why the best practice in using Amsoil synthetic lubricants is to stick with what they recommend.
By all means, if someone has a question or needs further clarification, please do not hesitate to email me or PM me. I will be more than happy to help out in anyway I can.