bobmoore2

While I was running really hard last weekend at WSIR, I pulled it out of third gear and it would not go into second. ... or back into third or into fourth or even 1st. So I coasted to the side of the track. I sat there for about 2 minutes. Then I put it into gear OK, and I drove it off the track. Nothing was leaking (not a drop on my spot in the paddock the whole weekend.) I didn't do any more DE sessions that day, but it shifted fine all the way back home and on my commute the following day.

The car is a 2000 with a MN6, not a Z06. Absolutely no engine or drivetrain mods. It seems obvious to me that something is getting too hot, but I don't know whether it is the transmission or the clutch. Has anyone else seen this problem? Do I need a cooler for my MN6?

P.S. Please don't ask me what my transmission temperature was. I don't know, because the 2000's do not include the transmission temperature on the DIC.

01C5fan

Probably the clutch slave cylinder. There are at least a couple of aftermarket replacements that are popular. Sometimes just bleeding the fluid will do the trick. I think there is a kit you can install that makes bleeding easier (it's a pita otherwise). I can't remember all the specifics, but this is a common problem that has been discussed at length on the forum. I'm sure someone will chime in with better info.

SouthernSon

Yeah, the clutch slave cylinder. Some just extract what fluid they can with a turkey baster and replace new fluid after each event. This helps. However, if you ever need to get to the drive train, just install the remote bleeder for future use while you have the thing disassembled. This just simply involves running a line up into the engine compartment at the back from the slave cylinder to provide easy access (after one has disassembled the access panels to the tunnel which requires removing everything else under the car).

bobmoore2

After the two replies above, I did a search on "clutch" and found several threads about clutch problems in the C5 Tech section. However, I'm not sure they are talking about the same problem I have.

The threads that seem to be referencing my problem talk about the transmission refusing to go into gear (my problem), but they also talk about the clutch pedal feeling soft or just going to the floor (not my problem). So I'm wondering if that clutch problem is not my problem.

I have noticed that my clutch fluid is very very dark and has some "gunk" in it. So I will follow the fluid change procedure, to get the fluid clear again. I'm just hoping that actually fixes the problem. I won't be able to confirm it's fixed until my next track day (about a month away), because that is the only time I see the problem.

I'm open to any other ideas about what could be causing my problem.

Thanks for all the help so far...
Bob

Lawdogg

Happened to my MN12. Sounds more like something broke in the tranny and was wedged where it didn't belong.

davidfarmer

Mine did that when the synchros were going bad, but mine was grinding. It would shift great for 2 laps, then get harder to shift, ultimately locking in 3rd gear. Wouldn't come out until I came to a complete stop.

SouthernSon

My dear Mr. Watson, this is the operative clue; "While I was running really hard last weekend at WSIR,"

I would be really surprised if you did not boil the vapor in the clutch system and therefore need to flush as recommended in the first few posts.....

One does not always 'feel' a pumped up, dirty, vapor laden clutch line, especially on a track while adrenaline is pumping and you are searching frantically for that next gear...

Besides, you are not really gonna tear the tranny apart before simply flushing that line to see if it resolves the problem, are you?

bobmoore2

Again, Mr. Holmes, your logic is impeccable.

I'm going outside to flush the clutch fluid in just a few minutes.

By the way, when I got into the car about 8:00 last night, it wouldn't go into reverse and was difficult to get into the other gears. So I now know that the problem is not always temperature-related.

Dr. Watson

davidfarmer

NEVER had a clutch fluid problem. Besides, you can get a car in and out of gear WITHOUT a clutch, just by unloading the drive-train and rev-matching.

While it certainly could be a clutch issue, especially if bleeding the fluid isn't a regulary item on your service list, sounds more like a trans problem to me.

I hope it IS a fluid issue!

BQuicksilver

Sounds vaguely like what I'm dealing with. I think my clutch needs bled more as it's not fully disengaging and gets VERY notchy, with 1,2,R sometimes very tough to engage.