Quote:
Originally Posted by Finnegan
But that doesn't get us to a solution. And that is what most of us are after.
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I don't know what the solutions may be. The 3rd->2nd problem: no idea what causes it, never had any trouble. Maybe stiffer bushings might help, maybe not. But not by the means I displayed before imho, but of course there might be another problem. Maybe the linkage itself blocks (there are 2 joints). I don't know. I also can't imagine how it feels, so I have no hints on what part is failing
The 1st-2nd grinding is definately a synchro problem (the grinding teeth are a dead giveaway
. You say synchro's don't repair themselves, but maybe they are not broken?
As I understand it happens during acceleration, mostly full throttle (obviously) and primarely with /m cars and less with normal cars who use the same gearbox. Although that last remark is not completely true: the GS6 box is a co-production between ZF and getrag (it's zf design though). the GS6-37BZ units are afaik ZF and the GS6-37BG units are Getrag made (the letters Z and G are a giveaway
). So that might be a reason some experience it and others dont (difference in production tolerances etc; the boxes should be the same but you know
).
A second difference is that m cars (s54) rev much higher; the diff ratio is also much bigger. So the speed difference between a running gear and a stationairy gear is much bigger. And that's what a synchro has to overcome. Maybe they are not fully up to the job.
Where the problem lies in the synchro's: I don't know. It could be a number of places:
The synchromesh consists of a synchronizer hub (with inverted cone) that sits on the splined output shaft (the splines make it a solid connection that can move forth and back). Around the synchronizer hub sits the synchro sleeve (also connected with splines to the hub), and that sleeve is centered with springloaded balls. When you shift and you feel the click that the transmission falls into a gear, you feel that the synchro sleeve shoots out of a groove which was held in place with those springloaded balls.
That happens after the synchro cones where pushed together to match the speed difference. If the groove is too wide for those balls, the sleeve can move around, and maybe that causes the grinding (the sleeve moving foreward a bit and hitting the gear before the synchro's had the chanche to fully revmatch)?
And in the synchro sleeve is another groove in which the shiftfork sits. Maybe that is too wide and pushing the lever to the left pushes the shiftfork a bit against the synchro sleeve so it cant wobble around?
Anyway: none of these potential problems with the synchro can be fixed with stiffer transmissionmount bushings imho. Its a problem with teeth of the synchro sleeve touching the teeth of the drive gear too soon for the speed being matched up by the synchro (the cone and inverted cone pressed together). I can't imagine how a bushing can influence that.
If you want to be shure not to grind the teeth, imho you have to double clutch, or adjust the rev range (more rev matching), or do something to the synchro's etc.
But by all means be free to experiment. I'm more of a think before you try kind of guy
The thing that sometimes bothers me is that I see/read explanations presented as facts by people which are completely impossible and make absolutely no sense. But... that's the internet. I have to live with it
