4th gear grinding
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
4th gear grinding
I took my 93 LT1 to the drag strip today. And I did 5 runs with it. And 3 out of those 5 runs my 4th gear grinded when I shifted. I noticed that 4th gear only grinds when the transmission is under lots of load(shifting at red line). Could this mean the end of my transmission and am I looking at one of those expensive rebiulds. Or is their anything else I can do. So far the clutch slave was replaced about 5 thousand miles ago.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
update
Ok so I just read some stuff on the ZFDOC website and it says to check the clutch fluid. So after looking into that I looked in the resevior and I noticed it was completely empty. And what little fluid was in there was completely black. Could this be a contributing factor to my gear grinding problem?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Of course it could and very very likely the cause of your grinding. No fluid could mean air in the master cylinder which greatly reduces the hydraulic pressure when you push in the clutch and thus the clutch doesn't get fully disengaged causing grinding. If the liquid was black, you should at least flush the fluid and replace it. Black fluid is a good indication that you have water in the fluid and this corrodes the master and slave bore causing fluid leak and master/slave replacement. All hydraulic fluid should be flushed at least once a year because it is normal that water condensation gets into the fluid and starts corroding the master and slave bores.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
Ok I am going to change the clutch fluid on Monday. It just seems odd that only 4th gear is grinding on me. A few weeks ago I changed the transmission fluid with that synchromesh stuff that everybody swears by. Could it also be that I put the wrong stuff in?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
I doubt you used the wrong transmission oil. 4th grinds during shifting at the track because the engine is at high rpm and you are shifting fast and the synchronizer ring on 4th gear can't instantly match the speed difference up with the clutch, not to mention that your clutch may not have been fully disengaged. If you drove home, I'll bet 4th didn't grind because of much lower rpm when you shifted.
Also, it is a bitch on C4's to bleed clutch systems when you replace the fluid. It is difficult to get all the air out. The last time I did a clutch hydraulic repair, the clutch felt spongy and we finally gave up. On the third day going to work, the air was out of the system and my clutch felt firm.
Also, it is a bitch on C4's to bleed clutch systems when you replace the fluid. It is difficult to get all the air out. The last time I did a clutch hydraulic repair, the clutch felt spongy and we finally gave up. On the third day going to work, the air was out of the system and my clutch felt firm.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
I doubt you used the wrong transmission oil. 4th grinds during shifting at the track because the engine is at high rpm and you are shifting fast and the synchronizer ring on 4th gear can't instantly match the speed difference up with the clutch, not to mention that your clutch may not have been fully disengaged. If you drove home, I'll bet 4th didn't grind because of much lower rpm when you shifted.
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Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Bad synchro's grind all the time. You definetely have a clutch master/slave cylinder problem. Flush the old hydraulic fluid out until it comes out clean and bleed the clutch and then keep track of the reservoir level. If it stays up, you are ok, if it slowly or quickly drops in level, then its new master and slave replacement time. Check your brake and clutch reservoirs at least once a month.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
Update
Ok I changed out the clutch fluid and low and behold no more 4th gear grinding. As it turns out the low clutch fluid as well as the degraded clutch fluid was the contributing factor to the grinding issue. I guess the Clutch wasn't disengaging all of the way between shifts.
So now that I got that taken care of another couple of issues have arisen.
1. My clutch fluid keeps turning black. (kind of like really dirty oil)
2. My clutch fluid has a leak and I cant find where it is. I Changed the clutch slave about 2 months ago. However I did noticed a lot of corrosion on the clutch master cylinder where the resevoir attaches to it.
So now that I got that taken care of another couple of issues have arisen.
1. My clutch fluid keeps turning black. (kind of like really dirty oil)
2. My clutch fluid has a leak and I cant find where it is. I Changed the clutch slave about 2 months ago. However I did noticed a lot of corrosion on the clutch master cylinder where the resevoir attaches to it.
Racer
Joined: Sep 2002
Posts: 337
Likes: 2
From: New Orleans La
similar problem!
I don't have a shifting problem but lately I've been filling up the master
clutch cylinder every other day.
I don't see any thing on the ground and I'm trying to figure out if it's the master or slave cyl. that's leaking.
I'm thinking about changing both. I've seen a great price at drivewire.com They sell PBR brand.
Has anyone had any dealings with this site or brand?
Thanks in advance
Herb
clutch cylinder every other day.
I don't see any thing on the ground and I'm trying to figure out if it's the master or slave cyl. that's leaking.
I'm thinking about changing both. I've seen a great price at drivewire.com They sell PBR brand.
Has anyone had any dealings with this site or brand?
Thanks in advance
Herb
Safety Car
Joined: Jan 2006
Posts: 3,566
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From: Mt Laurel NJ
St. Jude Donor '06-'07
Go to http://www.zfdoc.com and read up on your transmission. If the master/slave is old, replace both, and the line. Use the GM fluid, it will last longer and work better.
Thread Starter
Instructor
Joined: Feb 2009
Posts: 191
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From: Woodstock IL
Another Update
Ok another update for you guys. I read lots of posts indicating that clutch fluid leaking onto your floor boards would be caused by a faulty clutch master cylinder. Well in my case, my leak was small enough that this went unoticed. By the time I felt around my floormats the clutch fluid would be long gone and dried up. However, I did find a small amount of fluid build up where the clutch master cylinder meets the clutch pedal.
Now I know where all of my magical clutch fluid is disappearing!
Now I know where all of my magical clutch fluid is disappearing!
