Hey there everyone,
I have been researching this issue for sometime now, and I think that I can offer at least a bit of information as to what is causing this issue and how I might be able to help a bit.
The Getrag gearbox uses a triple synchronizer set up, which consists of a inner cone ring, middle friction ring, and outer synchronizer ring. These rings are designed to work together to either speed up or slow down the gear depending on what is needed. ie either up shifting, or down shifting.
If for some reason the gear does not match up speed wise you get a grind as the operating sleeve makes contact with the gears dog ring. There are a couple of reasons why this can happen.
1) The gear oil does not have enough viscosity. A lot of synthetic oils as simply too slick and there is not enough friction generated quickly enough for the gear to match speed. We have seen this in the past with other similar Getrag synchronizer setups.
2) The clutch is not fully disengaging from the flywheel, which leaves the gear shafts to continue to spin even when the clutch is supposed to be disengaged. The synchronizer is not designed to work this way and again simply can not handle the work load and you get a grind.
From some of the pictures that I have seen regarding the actual damage done internally to the MT-82 transmission, I would say that these are the possible issues that need to be addressed. So the real question here is what can be done to correct this?
Well that is where things get a bit tricky. First of all there is a warranty issue to consider. While I know that Ford is not really going out of their way to correct this particular issue, there maybe others that would come up that would not be covered if they discovered that you had voided your warranty in some way.
The other issue is that if the damage is done, then it is done. The pictures that I have seen showed that several of the dog teeth on the gear face had been sheered away. This is caused when you pull too hard trying to get the car into gear and ran the operating sleeve into the dog ring while the gear was still spinning. If this has occurred then the dog ring will need to be replaced, at a minimum, and there could possibly be additional damage done internally from the pieces moving around the gearbox before they could be grabbed up by the internal magnet.
However, if the damage is minimal, then there may some fairly easy solutions available. The first one is obvious I would imagine. Replace the gear oil with a better solution, one that was designed to work with this type of synchronizer system. NOT SYNTHETIC, or at least not the ones currently being used. I do not wish to sound like I am promoting a particular oil, and I am not selling anything here, but if you would like a suggestion, PM me and we can talk at bit more about this.
The second solution would be to use a more aggressive friction ring to help increase the performance of this setup. This is what I may be able to offer to everyone in the future, but not currently, as I have yet to find a gearbox to diagnose and test on yet. There is a drawback to consider here with regard to this solution. Shifting will be a bit notchy, and may require a slightly quicker shift. Here is why this happens.
When you go to a more aggressive friction ring, the synchronizer will at time still not quite line up with the dog ring. The gear will be at the correct speed, but because the synchronizer is holding the gear with more force it will not allow the two pieces to easily slip into each other. You will not experience any grinding, but actual engagement maybe a bit notchy and a bit of pressure on the stick maybe needed to get the gear and operating sleeve to mesh up.
If this is a clutch issue, to where the pressure plate is not fully disengaging from the flywheel then there is another area that would need to be addressed.
The throw out bearing on this gearbox appears to be hydraulically actuated rather than moved via a release fork. If the TO bearing is not getting full throw then it is not completely disengaging the clutch, and this will certainly cause shifting issues. This could be something as simple as contaminated hydraulic fluid, or seal leak, or simply the wrong diameter Master Cylinder. There are a lot of possibilities for this one. I would check them all.
The easiest way that I can think of would be to turn the car off. Select 1st gear and make sure that it is fully engaged. Push the clutch in and hold it to the ground while starting the car. DO NOT RELEASE the clutch pedal. Let the car idle for a couple of seconds and see if you can smoothly engage 1st gear. Since you have not engaged the clutch since selecting 1st gear while the car was off, the gear shafts should not have moved and you should be able to smoothly select 1st gear.
You can also do this another way, both should work fine. With the car running and out of gear, push the clutch in and wait 5 seconds for any movement of the gear shafts to stop, try to select 1st gear as you normally would. There may be some resistance as the operating sleeve meshes up to the dog ring, but there should not be any grinding.
If you do hear grinding, then the issue here is inside the clutch and may not be an issue with the gearbox. This is not to say that there is not a problem with both however.
I really hope that this information is at least a bit helpful. I would really like to try to find a solution for everyone on this, as when it works correctly the Getrag units are typically some of the best shifting gearboxes around.
Feel free to PM me any questions you might have.
Last edited by CMS; 07-29-2011 at 03:54 PM.