Hard time down shifting at high RPM (track only)
 

Like i said, i'm having hard time down shifting without grinding at high RPM (track only). Mainly 4->3 at around 70 mph and some times 3->2 at around 35 mph.

I'm one of those people that would rather carefully put the car in gear rather than get that extra .1 seconds both accelerating and decelerating. I've always been super careful and gentle with my tranny and change the fluid often (Redline MT90). The last time i changed it was is late March and i've been to the track 5 times and put about 4k street miles on it since.

It was damn hot at my last track day. At least 105, maybe more. Could this have been why it was acting up? I dont think it would start to grind until at least half way through the session which is why i think heat might have been part of it but i really dont know.

Any ideas? Synchros? clutch? :dunno:

I have zero issues with street driving. Even spirited street driving.

2004 GT MT w/ 71k miles, original clutch/flywheel, engine, transmission etc

even clutch all the way?
do you do heel and toe?
sometimes you just need to slot the gear in quickly rather than slow.

I don't heel-toe on the 105->70 shifting from 4th to 3rd because the consequences of me screwing up my braking, turn in or balance would be pretty bad. Last track day was my first time on R-comp tires and race caliber pads so there was a lot to take in -- too much to heel toe IMO. It hasn't done it in the past when i haven't heel toed...

I tried quickly too. I didn't like the way it sounded or felt.

I'm not sure what you mean by "even clutch all the way". The clutch pedal was fully depressed if that's what you're asking. No different than before.

if the clutch is depressed all the way and you still grind, might be going syncros.:ylsuper:

Some one at the track seemed to think there maybe a way to adjust the clutch engagement point. Like maybe it wasn't releasing fully or quickly enough :dunno:

I dont know if there is a way to adjust it on our cars or if that would even do anything. Just thought i'd throw that out there.

you can adjust it but if its all the way already, then its not the clutch pedal.

steel clutch line, maybe is just the brake fluid that got heat up in the clutch system. change the line and fluid and see what happen first.

Bent fork ?

You are on the right path............

How many miles has your clutch got? Is your pedal welded\reinforced?

71k on the clutch

I have a SS clutch line, maybe I'll put it in this weekend.

My clutch pedal is reinforced with a bracket -- no extra welds. Feels solid with no squeaks.

May wanna replace the slave cylinder (or rebuild it) while you are swapping the clutch hoses.

It also seems to me that the bracket deals more with side-to-side motion and the welding deals more with the longitudinal motion.

I haven't swapped the clutch line yet but i did just move the clutch adjuster closer to the firewall. It seemed to bring the engagement point closer to me instead of right on the floor. This is the right direction for my issue right? Hard to tell since i can't really replicate track conditions on the street... or can i :naughty:

sure you can, your in ok which cant be to much different than our vast open highways of texas.

the transmissions are weak.

it will happen. only thing to do is replace the transmission.

I have had this problem since day one. I am going to change my fluid and see what happens. I just think that the transmisions and the shifters are to blame. Just not as solid as it should be for a 9K+ revving car. Basically if I know I need to shift at a high RPM (like if I see an animal in the road I might not get to in time...) I try and really pay attention to guiding the shifter in the perfect spot and I let off the gas a little. This is pretty hard for a straight guy but I'm getting better the more I drive at that RPM.

OK, i didn't get the hose in this weekend but i might try it tonight. I do for sure have a problem though because i can pretty easily replicate the issue down shifting from 3rd to 2nd in the higher RPM range. Are we all sure its a clutch issue or is it the tranny?

You should check your clutch wear\engagement points and then consider tranny wear as well.
A clutch that doesn't fully disengage may cause some grinding, other than slippage\accelerated wear for both its plate and the transmission etc, so it could be the cause or at least one of the factors that lead to excessive transmission wear.

I'd recommend changing the oil and bleed/flush the clutch line to start. You can check the clutch pedal adjustment, but if you alter it make sure you know what you're doing and triple check all your measurements before and after.

So I got the SS clutch line in. From what I can tell so far it did the trick. I wasn't able to replicate the grinding like I was able to do earlier today and I tried driving close to track like conditions ;)

I still think I may change my tranny fluid. It's only been 6 months but I feel like it should be done.

If you're tracking the car you can't change it often enough. I suspect bleeding the hydraulic line would have been sufficient, which you essentially did via the hose change. The OE cluth hose would have to flex out like a bologna sausage in order to cause this kind of problem. The stainless braided line is nice, but overrated.

After this last track day i think it was better but we still had some grinding. To recap i swapped in a SS clutch line, re-bled the whole brake and clutch system, changed the tranny fluid (Redline MT-90) and adjusted the clutch pedal to engage a little further out from the fire wall.

The grinding is significantly harder to get when heel-toeing but my current driving shoes are not sufficient for the job. They too narrow and slippery to do it consistently. I have a pair of Piloti's on the way so hopefully they'll help. Heel-toe master Dondo still had some issues with grinding even though he could blip the throttle almost every time.

Dondo and I also managed to locate a creak that was happening when we depressed the clutch pedal (car off). It sounded like it was coming from the engine bay down by the slave cylinder. Is this another sign that the slave cylinder needs rebuilt or replaced?