Gearbox grind, tried a few things, need help.

[180sxdan]

I recently bought a 180SX, 94 Blacktop SR20DET 5sp manual. Problem is when shifting in or out of any given gear it grinds when it feels like it, basically showing symptoms of the clutch not disengaging properly, shifting is also notchy. I say this because i have tried a few things. Readjusting the clutch pedal to push into the master cylinder harder solved my problem for a few days then got worse again. During that time the shifting felt much smoother, gear changes were easier and I had no problem putting the shifter in reverse or any gear for that matter.

There is a squeak I hear coming from the gearbox (probably the clutch fork needs regreasing/cleaning) so I changed the slave cylinder even though there are no leaks on either master or slave. However changing the cylinder didn't change anything.

My thought is that the pressure plate may be on its way out. I say this because the clutch doesn't slip so the clutch disc should be fine, bearings don't make any noise and the previous owner said the clutch pedal felt lighter over time. The clutch pedal feeling lighter led me to believe it was the hydraulic system but since I changed the slave cylinder I know this is not the case.
For the record I have put new gearbox oil (Castrol VMX80) and clutch fluid in.

Can anyone confirm or deny the clutch pressure plate may be on its way out? At this stage I think I'll have to buy the kit and change it all out (disc, plate and throwout bearing).

edit: could a worn clutch fork also be another possibility? is there any way of telling which is the problem here?

Cheers.

[waxdnuggz]

Definitely sounds like the clutch is on its way out. Has anything happened recently that changed it to this or that's how you got it? The squeak is most likely the clutch pedal like 99% of 240sx's. Welcome to the forums if your clutch pedal doesnt seem yo come up as far then you know 90% of the time is hydraulic make sure you check inside the cabin to make sure its not leaking Are you missing any fluid?

[180sxdan]

This is how I got the car but the grinds weren't as loud at first and were much rarer. I've actually been working on removing the gearbox these last few days and it should be coming out tomorrow (all bolts are loosened just need the car high enough to pull it out). With all I've gone through to pull this box out and then will need to do to put back in what do you recommend changing out to make sure the gearbox is good for at least a few years... even a decade?

Without seeing what the damage is at this point I'm guessing I'll be needing a clutch kit so pressure plate, clutch disc and throwout bearing. Just curious what else would be good to bring up to date... First things to come to mind are clutch fork, pivot point and input shaft bearing, not sure if the spigot bearing and rear main seal are worth changing out too. I will also be removing the rear housing of the box to check the condition of the gears as well.

I am not missing any fluid the level is fine, I am sure the hydraulic system is ok. As for the squeak I've put my ear up to the gearbox and can hear it from the fork, I can also feel the vibration coming from it.

[waxdnuggz]

Honestly if your going to open it either replace the forks and syncros or try to find a cheap ka trans that you know works and swap bell housings.

If your pulling it off replace the rear main seal. And check the condition of the freeze plug back there. I find it way easier to rip the motor and trans out as one unit. I've done my fair share of dropping just the trans and I hate it that way. Just my .02

[180sxdan]

Yeah when I get the box out I'll post a photo of the gears to see if anyone has any opinions as to what's actually worn and needs replacing, but since it's only been like this for the last 200km or so so I don't think the box will be in such a bad condition... specially since adjusting the clutch pedal made the issue disappear temporarily.
I don't have an engine crane so I can't go that route, I do have a jack with an gearbox mount so that's why I've opted to do it this way, the only problem I have at the moment is getting the car high enough to pull it out easily. Buying some blocks soon and the gearbox should be easier to remove once that's done.

[180sxdan]

I think it's also worth noting the car only has about 135 thousand kms or 84 thousand miles on it so it shouldn't be too bad other than this clutch issue causing grinds... but I guess I'll find out once I look at the gears.

[180sxdan]

Took out the clutch today... couldn't see any obvious problems with the pressure plate or the clutch fork so I'm a little lost on what the problem was.
Heres pictures of the clutch disc to see how worn it was, it's my first time doing this so I'm not too sure on what's worn and what isn't.
Could this have been the cause of my problems?

[Nikita240]

That clutch looks f***.

P.S. I am no expert.

But when you said that adjusting the clutch pedal relieved the issue it makes me think it's either the pressure plate or the hydraulics. Have you bled the clutch lines?

[waxdnuggz]

That clutch looks f***ed.

P.S. I am no expert.

But when you said that adjusting the clutch pedal relieved the issue it makes me think it's either the pressure plate or the hydraulics. Have you bled the clutch lines?

That disc looks absolutely fine.... its an organic clutch disc and looks fairly new with tons of life left

[180sxdan]

That clutch looks f***ed.

P.S. I am no expert.

But when you said that adjusting the clutch pedal relieved the issue it makes me think it's either the pressure plate or the hydraulics. Have you bled the clutch lines?

Yes I had bled and put new fluid in the clutch lines before adjusting the pedal and I had the same problem... that's why I adjusted the clutch pedal since I thought that was my last hope before pulling apart the box.

The pressure plate looked ok, not horribly worn. Just the throwout bearing does show signs of being on its way out (small grind noise) but it still spins freely with no issues.

That disc looks absolutely fine.... its an organic clutch disc and looks fairly new with tons of life left

If the clutch looks fine then what do you think could have been the source of the problem?
I'm absolutely lost, replacing as much as I can but I really want to solve the issue.

Cheers.

Some pictures might help incase there's something obvious I'm missing, let me know if anything here is off or should be fixed. I'll be opening the box up to look inside and to change the input shaft bearing just to give it some extra life. I'm putting in an Exedy heavy duty clutch kit with a reinforced pivot ball

Inside of bell housing



Pressure plate side of clutch



Inside of pressure plate



Outside of pressure plate



Pressure plate at an angle view incase it's warped in some way

[waxdnuggz]

Let me ask you this. Have you deleted the box on the clutch line. That clutch looks fine other then a little heat spots. I think your problem could be in the trans its self. A ka and sr Tran is the exact same so if that's the case buy one for 100$ and swap bezel housings.

[180sxdan]

Let me ask you this. Have you deleted the box on the clutch line. That clutch looks fine other then a little heat spots. I think your problem could be in the trans its self. A ka and sr Tran is the exact same so if that's the case buy one for 100$ and swap bezel housings.

What do you mean by deleting the box on the clutch line?
And I will be opening up the box in the next few days to look inside and I will post photos.

Cheers.

[waxdnuggz]

There's a dampening box between the slave and hard line. Search. Do you still have it?

[180sxdan]

Hmm, I had a look online and from the pictures I've seen, from memory I dont believe I've seen that down there. I'm in Australia and it's night time here so I'll check tomorrow during the day to see if it's still there.

However I do know for a fact the line going to the slave cylinder is a braided line and from information online I understand that stock is a rubber line... so it's at least had that modification for sure... I will have to confirm tomorrow. Even though it's overkill I plan on bleeding the clutch system again to rule it out completely.

For what it's worth the clutch did feel hard/heavy which I understand is the purpose of removing the damper. The previous owner was under the impression that it had a heavy duty clutch which upon inspection it clearly did not.

So to recap, I think it may have been removed based on the reasons stated above as I don't recall seeing it there, but since I wasn't specifically looking for it it may actually be there and I haven't noticed. I will have a definitive answer tomorrow during the day when I'm under the car so probably in 14 ish hours from this post and I will let you know.

What is your theory on the clutch damper? Do you think its removal could be causing this problem?

Cheers.

[180sxdan]

I couldn't sleep thinking about this issue so I had a look under the car. The dampening system is still there and intact.
I see in this guide how the damper is bypassed, mine is not bypassed.
http://garage.projectraine.com/content_ ... amper.html

I gather you think maybe the dampening box is nearing the end of its life and is causing this issue? It is 20 years old so it wouldn't surprise me.
Except I don't see any visible leak or or brake fluid residue on the lines surrounding it.

Here's a photo to make sure we're talking about the same thing. The top line comes from the master cylinder and the braided line to my slave cylinder.



edit: I have not bled from this point, and from research online it seems like the damper box tends to trap air making the clutch not fully disengage... if this was the problem all along I can not believe I've pulled apart my transmission for something that could've been solved in 10 minutes...

[waxdnuggz]

Well I hate to say it but im willing to bet that's your problem. It does trap air and very badly. My clutch master went out a few weeks ago and I changed it on thw side of the road and I could not for the life of me get it to bleed properly. I wemt thru 2 big bottles of brake fluid and my pedal still wasn't coming up on its own so I ran to enjuku and got a steel braided line and bypassed the box and in 5 mins my car was back on the road driving me home.

[blkvrtswp]

I would definitely bypass the bleeder box, then remember that as a clutch disk wears, the engagement point when the pedal starts grabbing will move. That is what the pedal adjustment is for - to compensate for differences in disk thickness.

Pedal adjustment can be tricky to get right - make SMALL changes and test drive. The sweet spot is where you have no grind going into gear with engine running AND the clutch does not slip (go up a hill in 3rd with the gas pedal floored around 3500 rpm. If it's going to slip that will do it).

I once sold an SR swapped car and shipped it to Nebraska ($600). The new owner could not get the brand-new clutch to work right, so he shipped it back to me ($600). I had it fixed before the transport truck left my shop - all pedal adjustment. I had begged him to take it to a local mechanic experienced with hydraulic clutches.....but he took it to the Nissan dealer and they failed.

[180sxdan]

Well I hate to say it but im willing to bet that's your problem. It does trap air and very badly. My clutch master went out a few weeks ago and I changed it on thw side of the road and I could not for the life of me get it to bleed properly. I wemt thru 2 big bottles of brake fluid and my pedal still wasn't coming up on its own so I ran to enjuku and got a steel braided line and bypassed the box and in 5 mins my car was back on the road driving me home.

no no no don't hate to say it at all, I'm just incredibly happy to have most likely found the problem... and with the work I'm doing to the gearbox I'm sure I won't have to open it again for at least a few years. I will still be posting photos of my gearbox gears soon so I can get some opinions on its condition as I bought an input shaft bearing yesterday just to give the box more life.

I would definitely bypass the bleeder box, then remember that as a clutch disk wears, the engagement point when the pedal starts grabbing will move. That is what the pedal adjustment is for - to compensate for differences in disk thickness.

Pedal adjustment can be tricky to get right - make SMALL changes and test drive. The sweet spot is where you have no grind going into gear with engine running AND the clutch does not slip (go up a hill in 3rd with the gas pedal floored around 3500 rpm. If it's going to slip that will do it).

I once sold an SR swapped car and shipped it to Nebraska ($600). The new owner could not get the brand-new clutch to work right, so he shipped it back to me ($600). I had it fixed before the transport truck left my shop - all pedal adjustment. I had begged him to take it to a local mechanic experienced with hydraulic clutches.....but he took it to the Nissan dealer and they failed.

How much pedal free play do you recommend? I've read about 1cm or half an inch max. The clutch pedal had sooo much free play probably around 2-3 inches or 6cm so it was definitely out.


Sorry I'm used to the metric system so I'm switching to approximate imperial values to make sure i'm clear.

[waxdnuggz]

It should be between 1 and 1.5 cm but closer to 1. Don't judge the pedal feel wothout the trans being in tho. You need pressure back on the cyl from the fork and if you have that much play you definitely have air in your lines unless you just have the clutch adjuster all the way in. If you have an oem master there should be about 1 cm sticking out of the rear of the fork that goes around the pedal maybe ever a little less then that.

[180sxdan]

It should be between 1 and 1.5 cm but closer to 1. Don't judge the pedal feel wothout the trans being in tho. You need pressure back on the cyl from the fork and if you have that much play you definitely have air in your lines unless you just have the clutch adjuster all the way in. If you have an oem master there should be about 1 cm sticking out of the rear of the fork that goes around the pedal maybe ever a little less then that.

Yes I have actually taken out and cleaned the master cylinder so I'm familiar with it, it had black stuff in it so I bled the old brake fluid and put new fluid in.
And the clutch pedal adjustment I will do at the end once it's all finished.

I opened up my gearbox today, everything looks pretty good minus a couple of small chips here and there but the gears aren't very worn... reverse gear which I made the worst noises in was in great condition, not even a chip so it shows these things were built to take a beating. Ofcourse this is the first time I've opened the gearbox so I don't have much experience, following are some pictures I took for any feedback as I'd like to know your thoughts on it. Synchros also look much better than I expected.
The input shaft bearing was in perfect condition so I didn't feel the need to change it like I planned.

I also noticed yellow paint on a couple of the gears, does this mean the box has been previously reconditioned?

all gears



better view of 1st



2nd



2nd and 3rd



3rd



4th



5th/rev

didn't pull this one out much of the case as I was worried about putting it back in so it's a bad quality photo.

[Alisaihin]

Those gears look fine to me. I don't see any real damage.

Also...reverse...does it make a mere whining noise? If so that's normal on a manual...