Clutch diagnostic advice needed
02-26-2014, 12:30 PM
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Clutch diagnostic advice needed Hi guys,
I've spent quite some time searching these forums so as to not start duplicate threads. If I missed one and am doing so anyway, I do apologize. Found several similar, but none seemed to match quite 100%, so I wanted to ask before I started spending money.
I have a 2002 Trans Am WS6. I am the original owner - bought it in July 02 with like 9 or 9.5 miles on it. Some background that may (or may not) be pertinent: I totally babied it until I could get SLP SFC professionally welded in, that was about 4000 miles. After that, I felt comfortable throwing it into corners, but am not one for drag racing. Never been to a strip, or even a real road course (can't afford that, so just back roads for me sadly). I've had it up to 100 once, can't remember going beyond that. Did "race" (if you can call it that) one guy in a crap car at a light once since he was annoying me for several miles prior to that. It now has just shy of 21,600 miles on it.
Garage kept, driven only locally on nice days, that sort of thing. Fun for me is the winding back roads, so I really don't beat on the engine or drive train at all.
This past summer it started to develop a problem - when sitting at a light, with it in gear and holding the clutch (as was my habit), it seemed to engage super low. I found if you hold the clutch pedal to the floor with it in gear for a few minutes, the car will actually start to move and it won't want to come out of gear. I even had it stall on me once like that.
Looking around here, one poster said he had similar symptoms and flushed his fluid by replacing the contents of the master, then driving it a bit, 5 times. I tried that. It seemed to be doing the job of flushing, but, not of changing the behavior. Now the fluid is clean even after pumping and driving it.
It does not appear to be leaking fluid. Nothing is on the floor and the level of the master doesn't seem to be dropping.
The clutch itself seems to be functioning mechanically as I stalled it this weekend in a parking lot (accidentally), so I assume it's grabbing. Would it have enough bite if there were fluid in the bell housing?
Other info to add, it seems to be inconsistent. Sometimes it'll lose pressure quickly, other times it seems like it's ok. When driving, it's perfectly fine. At highway speeds it feels like you don't even need to push it to the floor to shift, it feels great. And if you leave it out of gear and stay off the clutch at lights you can drive around the problem just fine, rendering it a nuisance more than anything else. But I worry about it getting worse and/or being a symptom of potentially larger problems, so I would like to make it right.
Any thoughts?
I've spent quite some time searching these forums so as to not start duplicate threads. If I missed one and am doing so anyway, I do apologize. Found several similar, but none seemed to match quite 100%, so I wanted to ask before I started spending money.
I have a 2002 Trans Am WS6. I am the original owner - bought it in July 02 with like 9 or 9.5 miles on it. Some background that may (or may not) be pertinent: I totally babied it until I could get SLP SFC professionally welded in, that was about 4000 miles. After that, I felt comfortable throwing it into corners, but am not one for drag racing. Never been to a strip, or even a real road course (can't afford that, so just back roads for me sadly). I've had it up to 100 once, can't remember going beyond that. Did "race" (if you can call it that) one guy in a crap car at a light once since he was annoying me for several miles prior to that. It now has just shy of 21,600 miles on it.
Garage kept, driven only locally on nice days, that sort of thing. Fun for me is the winding back roads, so I really don't beat on the engine or drive train at all.
This past summer it started to develop a problem - when sitting at a light, with it in gear and holding the clutch (as was my habit), it seemed to engage super low. I found if you hold the clutch pedal to the floor with it in gear for a few minutes, the car will actually start to move and it won't want to come out of gear. I even had it stall on me once like that.
Looking around here, one poster said he had similar symptoms and flushed his fluid by replacing the contents of the master, then driving it a bit, 5 times. I tried that. It seemed to be doing the job of flushing, but, not of changing the behavior. Now the fluid is clean even after pumping and driving it.
It does not appear to be leaking fluid. Nothing is on the floor and the level of the master doesn't seem to be dropping.
The clutch itself seems to be functioning mechanically as I stalled it this weekend in a parking lot (accidentally), so I assume it's grabbing. Would it have enough bite if there were fluid in the bell housing?
Other info to add, it seems to be inconsistent. Sometimes it'll lose pressure quickly, other times it seems like it's ok. When driving, it's perfectly fine. At highway speeds it feels like you don't even need to push it to the floor to shift, it feels great. And if you leave it out of gear and stay off the clutch at lights you can drive around the problem just fine, rendering it a nuisance more than anything else. But I worry about it getting worse and/or being a symptom of potentially larger problems, so I would like to make it right.
Any thoughts?
02-28-2014, 12:04 PM
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Thanks for the help! 
Yes, it is the original master, no aspect of the system has been apart (other than the cap to the master reservoir to change the fluid). I'll give that a try and will report back. It may be a couple weeks, but when I do, I'll post the results.
Yes, it is the original master, no aspect of the system has been apart (other than the cap to the master reservoir to change the fluid). I'll give that a try and will report back. It may be a couple weeks, but when I do, I'll post the results.
08-18-2014, 01:18 PM
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Turned out to be a few months, rather than a few weeks, but I finally was able to order a new clutch master (AC Delco, from Amazon) and install it. Did the drill mod in the process.
You were absolutely right. It works perfectly now. It will hold pressure at a traffic light once again like it used to.
There have been some changes, it feels like it coasts faster with the pedal fully pressed, and it seems to start to engage earlier/lower with less total range from start of engagment to fully engaged (like the top of the pedal travel doesn't do as much as it used to). I don't know if that is down to the replacement part being metal, vs the factory being plastic (bodied), or the drill mod. I suspect the latter. But it works great.
Thanks for your help!
You were absolutely right. It works perfectly now. It will hold pressure at a traffic light once again like it used to.
There have been some changes, it feels like it coasts faster with the pedal fully pressed, and it seems to start to engage earlier/lower with less total range from start of engagment to fully engaged (like the top of the pedal travel doesn't do as much as it used to). I don't know if that is down to the replacement part being metal, vs the factory being plastic (bodied), or the drill mod. I suspect the latter. But it works great.
Thanks for your help!
08-19-2014, 09:46 PM
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In case you check this thread again - I went through several replacement master cylinders. There is sort of a known issue with the clutch hydraulics in the 98-02's. My theory is that gm hamstrung the clutch to protect that weak "Barbie" 10 bolt axle from the torque of the ls1.
In the long run, you will probably want to get a tick master cylinder. Yes, they are very expensive, but the one thing I've seen routinely fix inconsistent clutch issues.
Second, the adjustable pressure plate that shipped factory can also cause similar issues. Highly recommend a monster clutch kit, which would pretty much take care of everything and address what I consider design flaws.
In the long run, you will probably want to get a tick master cylinder. Yes, they are very expensive, but the one thing I've seen routinely fix inconsistent clutch issues.
Second, the adjustable pressure plate that shipped factory can also cause similar issues. Highly recommend a monster clutch kit, which would pretty much take care of everything and address what I consider design flaws.
08-20-2014, 09:34 AM
#6
In case you check this thread again - I went through several replacement master cylinders. There is sort of a known issue with the clutch hydraulics in the 98-02's. My theory is that gm hamstrung the clutch to protect that weak "Barbie" 10 bolt axle from the torque of the ls1.
In the long run, you will probably want to get a tick master cylinder. Yes, they are very expensive, but the one thing I've seen routinely fix inconsistent clutch issues.
Second, the adjustable pressure plate that shipped factory can also cause similar issues. Highly recommend a monster clutch kit, which would pretty much take care of everything and address what I consider design flaws.
In the long run, you will probably want to get a tick master cylinder. Yes, they are very expensive, but the one thing I've seen routinely fix inconsistent clutch issues.
Second, the adjustable pressure plate that shipped factory can also cause similar issues. Highly recommend a monster clutch kit, which would pretty much take care of everything and address what I consider design flaws.