rx7sR1

i have a 86 n/a that when shifting from 1st to 2nd above 3500rpm my transmission scrapes.
i was just wondering if its my transmission or something else.

thanks for the help,
aaron

jarrod

If its a grinding sound,just a quick idea
try adjusting the rod underneath clutch peddle(to master cylinder)out a little that should give you a little more play...
Just an idea........

rx7sR1

thanks a i will try that but it onlydoes it from 1st to 2nd when ive beat it hard at all that day

90 White GTU

syncro's probably....happens on most 2nd gen's (including mine). Shift a little slower and it won't do it. Or change the trans fluid to Redline MT90 and that should help.

~Mike

Project84

The syncros speed up the layshaft when you downshift. If you go from 2nd to 1st, the shaft has to speed up since 1st gear turns faster at a given speed, (say 20mph) than 2nd gear. The syncros speed the shaft up when you engage the clutch. Back in the day, cars didn't have syncros so you had to double clutch. I will explain how so you can try it and see if you still get the noise.

This works for any gears, but I will use 5th and 4th.

Let's say your cruise at 65mph in 5th. grandma is doing 57 in the left lane and you run up on her and want to pass.

5th gear and the lay shaft are spinning at the same speed. (lay shaft is the shaft with gears on it in the tranny) This is what you do. Foot off gas, Push clutch pedal. (lay shaft slows down, engine slows down, car cruises.)

Shift into neutral, let clutch pedal out. (lay shaft connects to engine when clutch is out. your in neutral, so you can't accelerate yet.) now lets say in 5th gear at 65mph, your tach reads 2400rpms. If you were to put it in 4th at 65mph, tach would be at 3500rpms.

Knowing this, now that your in neutral, rev engine to 3700 rpms. This lets you speed up the layshaft since its connected to engine.

Now push clutch in, shift into 4th. Lay shaft and engine slow a little, dropping to about 3500rpms. The exact speed that 4th will spin at this given mph. clutch out, gas it, kiss grandma goodbye!

That is how you syncronize your gears since the smaller gears makes the layshaft spin faster than it would on the next gear up at the same mph speed. The syncros speed up the shaft when you move to that smaller gear. I've never really heard of double clutching when shifting up since the shaft is spinning too fast and will slow down when you let off gas and clutch in to make a regular shift. If you let your engine drop down to about idle when you shift, layshaft slows down on its own. Oh, and let the clutch up smooth and steady. Don't side step it, or just let it spring up off the floor on its own unless you have a drag racing clutch. If this doesn't make sense, or if you have more questions, you can PM me.