Originally Posted by Cdn17Sport6MT
Well, it is possible that the clutch delay valve may play a role... Now I'm not 100% sure how that works, but I would surmise the CDV has a non-return valve in parallel with it... so that you can push-in the clutch as quick as you like, but your attempt to let out the clutch abruptly slams the non-return valve (AKA "check-valve") shut and then the clutch fluid goes thru the orifice that is the CDV, at a certain max rate. If I have this logic correct, then the CDV prevents you from smacking it into higher gears as you accelerate.
If I have this right, then it is NOT the CDV that is screwing things up.
Instead, if the clutch is not totally disengaging when the pedal is on the floorboard (i.e., really, at its pedal-down limit-stop), then the engine is continuing to influence what's happening inside the transaxle... until it truly spins-down. And so, a bit of a delay in shifting gears to allow this spin-down to occur might mitigate the gravelly feeling. If this theory is correct, the gravelly feeling is 'cuz the synchronizers are not strong enough to control both transaxle shafts/gears - AND engine. No synchronizer is designed for that. That is why full disengagement is necessary to have long synchro life.
So, interesting theory... Give it a try and see if it bears-out.
You, sir, have a lot of knowledge in these matters. Impressive. To date this makes the most sense to me. I wonder how temperature could influence disengagement.
If this is in fact the issue and if I've been prematurely wearing the synchros because of this and due to the dealerships inability to address the issue after 4 visits, I'll expect some form of extended warranty on the transmission.
I'll experiment a bit in the morning with the clutch on the floor pause. I suppose others might double clutch instead..
It pains me that the cold shifts are so gravelly (good way of putting it). I always try to take excellent care of my cars, and it's troubling to know I could be wrecking synchros. Or, shall we say, the car may be wrecking them... I'm honestly just tired of it. I bought a Toyota to avoid reliability problems. Literally everyone I know with Toyotas have had zero issues.