Short story: stick is almost impossible to get into gear when it is cooler out (starts around 60 and gets worse the colder it is), but once the car is warmed up for 10ish minutes, drives like new. New trans fluid (MT-85) thrown in there a few weeks ago and didn't make a difference.

Long story: I've had my 06 manual Z since 2014 and a few of those winters were spent in Cincinnati, OH, where I drove it no problem in subfreezing temps. This winter in Texas, the stick became almost impossible to put into gear once we hit <40F days, but letting the car warm up for about 5-10 minutes almost completely alleviated the problem (any leftover resistance faded as I would drive).

At any rate, I figured I should perhaps change my trans fluid because I hadn't done it since I bought the car and had put about 50k on it so I went ahead and used Redline MT-85 at the suggestion of many a forum thread. Guy at the shop said my old fluid didn't look bad, for the record. It was warm that week and the car was shifting like butter.

Fast forward a couple of weeks to now; it's cool out again and I'm having the same problem. Stick is basically unable to go into gear until the car is warmed up, then drives perfectly fine.

I did discover today that the stick will shift into gear perfectly fine when the car is off, regardless of the outside temp. You can put it in gear, turn it on, then drive, but good luck getting into 2nd without summoning the strength of your ancestors. I literally hurt my shoulder today driving to work as I didn't have time to let it warm up much.

It's been suggested to me that I try replacing the master cylinder next, but I wanted some input on here before I moved forward.

Any feedback is appreciated.

 

my vette is notchy until it warms up

 

When was the last time you changed/flushed your hydraulic clutch fluid?

Sounds similar to a problem I had after I changed my clutch and replaced the master and slave cylinders. Clutch fluid level was too high and prevented the excess fluid to flow back into the reservoir during shifts. It shifted fine while it was off. Might not be your problem, but something quick and easy to check.

 

This isn't just notchy. I'm saying I am physically unable to get it into gear for the first several minutes. Like I'm shoving it so hard that I'm worried about damaging something and it still won't make the shift.



Word I haven't checked that yet. Only thing I've done so far is flush trans fluid.

Am I able to do this myself or should I bring it to a shop?

 

Checking the fluid is a solo job. Just pop the hood and take off the cap to the reservoir to see what it looks like. It should be fairly clear with a yellow tint. It's under the cover marked "Brake Fluid."

If it's dark or some other color, probably time for a change. Of course, if the seals in the master or slave are toast, then it's time for a rebuild or upgrade to a Wilwood or Tilton master cylinder. You won't be able to figure that out without taking it apart.

I think OEM fluid is DOT 3. You can use DOT 4 and DOT 5.1, but NOT DOT 5 as that is a silicone-based fluid.

Bleeding the fluid is a somewhat finicky procedure and you'll need two people. It's not the typical pump/bleeder screw protocol. If I were you, I would try draining, refilling, bleeding the clutch fluid first. If that doesn't resolve it, then replace/upgrade the master. Might as well do the slave while you're at it and a good time to go with a stainless line. If you do upgrade with the Wilwood or Tilton, get a reservoir that has a compatible cap for a Motive Power bleeder and then you can bleed the easy way with only one person and avoid the annoying bleeding procedure.

 

Usually that only happens when you are using not synthetic fluid and it is VERY cold out and a heavier weight.

With the vehicle off does it go into gear fine when it's cold? If so, then the clutch it not completely disengaging

 

Try shifting in to 2nd gear, and then first. Report back.

 

It's warm here now so I'll have to wait for a cool morning to get some more info for you guys. Will report back as soon as I have something to report. Thank you for the responses.

 

Alright an update: It was in the 40s here today and the car was damn near impossible to get into gear again without like 15 minutes of warming up first.

I did, however, come to the realization that the normal loud 'clack' sound that happens when you let off of the clutch pedal (very easy to hear in my garage) is nonexistent when I'm having this problem.
I'm guessing maybe the clutch is not completely disengaging and is what is causing this issue?

 

Once again. . .
With the vehicle OFF does it go into gear fine when it's cold? If so, then the clutch it not completely disengaging

 

Yeah shifts no problem so guess that's the culprit.

What needs to be replaced in order to remedy this?

 

Bleed/flush the slave with dot4 fluid and verify it holds pressure when held down(have someone look at the slave bar and make sure it doesn't retract)