1sic7

i heard the same thing from my rotary guy (smokin joe) and he said the stock NA Tranny can hold up to 500 hp

ColinRX7

Probably!

mazdaspeed7

I think its time for me to tear down that last n/a tranny I killed and take pics. I can assure you much more than just the synchros are broken...

j9fd3s

we broke the diff mount too , you must be some kind of animal adam, we've got like 6 guys to break the car, and you're just you

marcus7

I’m not a transmission rebuilder, but I have seen a few disassembled. How do you break a synchronizer ring in a manual transmission? I’ve seen worn out, and/or overheated synchros. I’ve seen broken dog teeth, busted collars and snapped countershafts, but what does one do to “break” a synchro? I’m not saying you didn’t do it, I’m just wondering how.

mazdaspeed7

Id go through a diff mount a week if it wasnt for my camber link. Ive got the diff nearly wedged against the floor. I can hear a nice *thwack* when i shift hard from the diff hitting the floor.



And yes, I know Im not nice to transmissions. The grabby clutch, sticky tires, and strong engine arent exactly making its life easy either.

j9fd3s

well when you shift the synchro is pushed against the cone surface on the gear, to stop the gear. if you push too hard the synchro will snap, as you're trying to push it over a cone, or the gear is trying to make it bigger. once its snapped, it lacks the strength to grab the gear anymore and it will grind badly.

marcus7

If I understand how the transmission works, my FC NA manual has what Mazda refers to as a hub assembly (AKA engagement collar). The synchros are attached to both sides of the hub assembly (each side is used for a different gear). When I shift, the cone on the gear, which is male, slips into the cone shaped area of the synchro, which is female. The friction between the two is used to speed up the hub and associated gear to match the rotational speed of the shaft so that they are both moving at the same speed before the dog teeth are engaged.



The only time the hub and or gear will stop moving is if the transmission's mainshaft is still (the car is not moving). Are you breaking parts while waiting at a light, or is the car moving at the time?



If a car is moving, and someone pushes too hard on the shifter before the hub and the shaft speeds have been synchronized, the sychro ring can overheat (hot spots and excessive wear), and/or the dog teeth can be slammed into position damaging the teeth on the gear, hub, or both. I've never heard of the syncro ring itself breaking, but like I said, I'm not a transmission tech and I suppose anything is possible. What you're describing really sounds like broken dog teeth, as that is what causes the grinding noise, not the synchro itself.



If the car is sitting still when the damage occurs, there is a clutch problem.

f.t.p. rotaryrocket

ok what if it was an s4 turbo engine. i know htey have significant power differences compared ot an s5. and also what if i babied the car till i could put an t2 drivetrain in the car. would hte car hold up.

i.e. if i didn't kill the car off of the line

ColinRX7

Yeah it would hold up, but you'd probably have to baby it pretty damn good..