Difficulty shifting 6MT Please help!
 

Hey everyone,

Lately Ive been finding myself having to use extra force to get the car into the next desired gear, Almost like the car doesn't wont to go into the next gear. This typically happens when shifting from 1st to 2nd but occasionally shifting from 2nd to 3rd and 5th to 6th as well. This problem is much more pronounced when the fluids are still cold and not up to operating temperature, and if it matters the gear box is filled with Motul synthetic atm.

Ive been searching through the forum a bit and apparently the syncros aren't the strongest but, while shifting requires some added attention/effort I'm not
crunching gears or grinding them either. I do however get the usual clunk when shifting from 1st to 2nd if i don't get the shift down just right, which is common and considered a normal characteristic for the 6mt. Now Ive also read that the csc is another apparent weak link in the z, and was wondering if this could be the problem? The pedal isn't mushy but my fluid doesn't look all that great, could there be a fault with it?

Picture of the clutch fluid condition below.

which Motul oil do you have in the box at the moment?
gearbox takes GL4 oil only.
diff takes GL5 only.

using GL5 in your box will destroy the syncros and make shifting difficult.

your clutch fluid looks like mine before the level kept dropping. keep an eye on it

I would rule out bad syncros. Usually you'll have one gear that is really hard to get into, but not all of them like you are experiencing. I would say that your csc or cmc is going bad. Sounds like the hydraulic system isn't building up enough pressure in order for the csc to be able to push in all the way on the pressure plate to disengage the disk.

* I would take care of the easy stuff. Bleed/flush your clutch fluid, and change the transmission fluid.

Yeah I'm pretty sure it's not gl5, the previous owner changed all fluids to motul and I'm pretty sure it's 75w90 gear lube.

As for the clutch fluid, it looks like the rubber that seals the csc might be deteriorating which is causing the fluid to change color. At least that's my take on it, everyone seems to think the color change is normal though.

Exactly what I was thinking, I'm really really hoping it's nothing internally wrong with the transmission!

I have some Motul rbf 600 that I plan on using when I flush the clutch fluid, I just need to find someone to help me do it or pay someone to do it for me.

As for the transmission, do you think I should go back to the Nissan stuff or keep it motul?

That fluid doesn't look too bad. It can go longer. The most common mistake would be someone put in 80w90 in the tranny. This will cause horrible shifting when the tranny is cold. It will be very stiff as you describe in colder weather.

I forgot to add that I have been sucking out the dirty fluid from the reservoir and topping it off with fresh fluid. I haven't actually flushed it out yet though, and last time I cleaned it out the fluid was pretty much black.

As for using the wrong weight fluid, I dont think that's the problem. Although I wish it was as simple as that!

What DOT fluid have you been using? DOT 4 changes to that brownish burnt color extremely fast.

And I agree about the wrong weight fluid not causing the problem. But it wouldn't hurt to change out it and see what happens. Remember, the manual tranny uses 75w-85, and make sure its a GL-4 gear oil. Flush the hydraulic system with some fresh brake fluid and go from there.

I'm currently using valvoline synthetic dot 3 & 4 brake fluid, but I have a unopened bottle of motul rbf600 that I'll be using when the system is eventually flushed out.

And while the color changing is considered normal, if you look at the picture I posted there seems to be some really fine black particles sitting at the bottle of the reservoir which dont seem to be normal.

So yeah I'll definitely be changing the fluids ASAP since it's the cheapest option and go from there, I'll keep everyone posted!

If anyone else has any Input please feel free to share!

Sounds like CSC is fixing to fail !

that does look like a bunch of metal particles in that fluid.
You're CQC or CMC is done.:shakes head:

That's what I'm starting to think too!

While I definitely think there is something up with the hydraulic system, the little particles in the reservoir are not metal. Last time I sucked up the dirty fluid from the reservoir there were little particles as well, and they just kind of mixed in with the fluid once I agitated it. :confused:

Its dirt/debris and clutch dust that makes it past the csc seal. Common problem.

I dont know what to say to u guys ive never seen those particles that big in my fluid, dont get me wrong i have personally bleeded my clutch twice and i only had particles coming out no bigger than sand grain size, those seems to be rubber cuts or something.

Just my two cents.

before i had my csc replaced, the fluid would go murky after about a week. black particles accumulated in the bottom of the reservoir too. i figured this was clutch dust getting past the seals.

new csc has been in there for almost 2 months now and the fluid still looks the same as the day i picked it up from the workshop

Like I said once I suck up the fluid, the particles mix in with the fluid and you can't see them anymore. Like MJB said, it's just dirt and debris that made its way past the seal.

Everyone is pointing towards the csc, but my pedal feel hasn't changed. :confused:

LOL, I just change it all. To me your just making clean dirty fluid if you just suck it out of the reservoir. .02cts free of charge... :)

Yeah I know, but I figured some fresh fluid is better than none. I dont have access to the proper equipment that is needed to flush the system out, which is why I just clean and top off the reservoir.

You only need a floor jack, jack stand for safety, and a vaccum pump brake bleeder. Suck all the fluid out of the reservoir, add new fluid, Get under car on drivers side, hook up vaccum pump, crack open bleed screw ( 6mm I think), pump until the fill bottle is about 1/4 full, check fluid, pump some more, check fluid, empty old fluid canister, repeat until you get clean fluid. Piece of cake.

I'm not sure why, but the FSM says not to use a vacuum pump on the hydraulic system. I've always bled it the way Joe@Zspeed recommends (gravity bleed)

It is a hand held vaccum pump. I see no issues with that. Now an electric one, oh yeah, it's just too much. I wouldn't use that.

UPDATE!

So I went to my local Nissan dealer yesterday to flush the clutch fluid out with some Motul RBF600, and the pedal feels way smoother than before! It's also a bit lighter than before, so it definitely needed to be changed.

After the fluid flush it still seemed a little difficult to get into gear (better but not perfect), I figured it would be a good idea to get a second opinion from a friend that is an experienced driver at this point. So we go for a drive, and my friend says it feels totally fine! He was also explaining to me the problem could be due to the quality of the shifting and technique (how embarrassing!), so I was showed proper shifting hand positions and my shifts instintly improved!

So I guess over the months my shifting technique bcame increasingly sloppy, which is embarrassing to say but I'll take that over any sort of damage to the drivetrain!

Oh and I almost forgot, thank you everyone for your input and advice, this forum is awesome and I'm glad to be a part of it!

That was an easy fix :tup:

Phew! :happydance:

Glad to hear that ! Shift on !!!!!!

Here is a video of how to heal/toe. Senna does it different than most. I never new this is how he did it but this is exactly how I do it also. Interesting.

Ayrton Senna's Heel-and-toe - YouTube