I have a 2007 Touring 6mt and within the past 500 or so miles, shifting into second has gotten rough. It is hard to describe. It is not 'grinding' per se, but about 50% of the time I shift from 1st to 2nd there is a distinct metal-on-metal feeling 'resistance'. Forgive me for this vague explanation. It's not a thunk, not a grind, just a hard shift where it takes an extra split second to go into gear, accompanied by some sort of metal on metal feedback (sans grind). I hate it. Does not occur if I shift into neutral first, and occurs both hot and cold.

Clutch pedal play seems fine, and engagement point seems fine as well (pretty low to the floor). The car almost always goes into first and reverse fine from a stop.

The transmission has also developed a slight whining sound going from gear to gear, as if the synchros are working a bit harder than they need to be. But again, no grind.

Gears 3-6 shift OK, but not as smoothly as they once did.

I suspected that my motor mounts could be to blame, so I filled them with 80a urethane this week. This helped shifting and made it smoother, but I still do get resistance, albeit less frequently.

Interestingly, I tend to get the most issues from 1st to 2nd while shifting at relatively low RPM's (<4k).

So I went in to inspect my clutch pedal (bracket seems OK, less than 1/2" of play in travel), however I noticed a very slow leak from the master cylinder piston seal. A very small amount of oil has dripped onto the firewall as well.

I bought the car with 65k miles and it now has 75k. I doubt the brake or clutch fluid has been changed (on my to-do list). I did change the trans fluid to Redline at the time of purchase, but I haven't ruled out the possibility that some has leaked (although I don't see evidence of that).

I've attached a picture of the piston I described. Could any of the experts chime in and let me know they think this could be the cause of my shifting woes? I know this is an issue that needs to get fixed (the clutch master), but I'm also trying to diagnose the shifting issues and figure out if it could be synchros.

Any other diagnosis steps I can perform to triage this rough shifting problem?

Thank you all in advance for your help and forgive my very long post.

EDIT: I should add that the clutch does not exhibit any signs of slippage and I treat it very well (never ride it at red lights, never race, never drag). I also take great care with shifting (never jam into gear, never downshift aggressively, etc).

 

If you see oil on the outside, it usually means there is air inside. Not always, but often enough.
I think you're in for a master cylinder change. Your symptoms sound to me like the clutch is not fully disengaging. You can bleed the master cylinder and see if that improves the shifting. You can also try to adjust the pedal to raise the friction point higher and see if that helps.

 

Update: spent about an hour trying to bleed the slave using my Mityvac. Could not pull much fluid through, lots of air. Seems indicative of air being trapped in the master. So master is definitely a problem. Ordered a new one and will install this week.

Has anyone here tried to bypass all of the steel hard lines in the clutch hydraulic system? Perhaps with a single steel braided hose? Would make for a much simpler system that could be fully bench bled before reinstallation. The placement of that slave bleeder screw is a PITA when trying to bleed in the car.

 

You can use a braided hose......it works perfectly fine You need an a adapter to -3AN for both ends...but they are available. I can look up the part for you if you need too...I think I still have the package from when I did mine

 

Awesome. Always thought about making my own with raw hose and fittings. Any idea on the length? Life would be so much easier if the whole thing could be bled outside of the car. I was even considering machining a bracket to add a standalone clutch fluid reservoir to the master.

By the way, also ordered a slave cylinder to do at the same time. I haven't inspected it thoroughly but assume it's probably either bad or about to go bad as well.

Any tips for removing and installing the slave without removing the UIM or oil filter? They are a pain to get to.

 

If you can get at it from underneath that is the easiest way....2 bolts with 12mm heads Ratcheting box end works well

 

Here's the bits 😊

M10 x1.0 male to -3AN male

BANJO TO -3AN male...not sure of the part #...will look and see if I can find it Or pull the banjo off the master and measure it

Earls -3AN brake line. ...part # 63010128. (28" long female to female)

 

I changed out the master and slave cylinders tonight and am pretty convinced I have some air in the system. The first inch of pedal travel (not counting the play before the rod begins to depress the piston in the master) is quite soft. I bench bled the master as well as I could (not perfect as I didn't have the circular hose-reservoir setup) but I think my bigger problem was with the hardline connecting to the slave. I could not for the life of me manage to disconnect the hardline where it entered the slave (just couldn't get my wrench on it) so I instead disconnected at the next fitting (the one on the bracket, where the hard line meets the hose). In doing this, I introduced air to the most significant 'kink' in the line.

I installed a speed bleeder on the slave by the way, and am not sure I like it. When my buddy cycled the clutch as we attemped to bleed, I could see the speed bleeder slowly suck back fluid/bubbles as he pulled the clutch in.

I'm thinking of reverse bleeding the system tomorrow (would have to swap the speed bleeder out for the standard bleed screw of course). Any other thoughts?

 

Wanted to provide an update. Replaced all of the clutch hydraulics and managed to get the system fully bled. I also adjusted the clutch travel, making it a tad longer. In tandem, these measures did help the hard shifting issue, but I still encountered the occasional clunk/grind/hard shift (especially going into 2nd).

So as a final measure, I replaced my transmission fluid. When I purchased the car (1 year and 10k miles ago), one of the first things I did was change the trans fluid to Red Line MT 90. The car had been shifting fine prior to the fluid change, I was just doing this as preventative maintenance. Upon changing to Red Line, the car shifted SLIGHTLY harder and gear noise was SLIGHTLY more apparent. Nothing serious though.

This past weekend, at the recommendation of BHR, I swapped the 10k-mile-old red line for ENEOS 75w-90. The car took almost EXACTLY 2 quarts of the new fluid (I drained/filled with the car perfectly level, using a bubble level). Old fluid was pretty dark and mucky, and the drain plug had a fair bit of metal shavings on it.

So far, I have around 75 miles on the ENEOS fluid and I am stunned at the difference it has made. I haven't had a single hard shift, and gear noise has all but vanished.

Now, in retrospect, I am glad I replaced the clutch hydraulics because i DID have a leaking master cylinder. But I'm not positive the hydraulics were the problem (yet). So for anyone experiencing the symptoms I had mentioned in my earlier posts, I highly recommend ordering 2 quarts of ENEOS gear oil and swapping it in. It's $20 a quart on amazon so $40 for the 2 quarts you'll need. It made a world of a difference for my transmission.

And i'm not bashing Red Line at all - I know many here have had great luck with it. I have no idea why I did not.