: clutch and rpm issues!! please help



06BlackV
06-21-11, 10:08 PM
hi i have an 06 V with 67k on the odometer, i noticed that if i press the clutch to change gears , my RPMS are taking too long to come back down therefore causing a slight jerk when i put in gear , im thinking its because the rpms are too high :( , also when im at speeds in excess of 35mph and i want to downshift , it wont go into a lower gear untill im under 35 mph , sometimes i can downshift into third at higher speeds but if i press the clutch to come out of third , its very hard to do so :( now keep in mind that i have no problems upshifting besides the rpm issue , i hope someone can tell me something , thanks ...nick

RADEoN
06-21-11, 10:13 PM
that's strange... maybe your clutch needs bled?

is it possible for a slave cylinder to stick halfway because of air in the lines?

06BlackV
06-21-11, 10:17 PM
i dont know how to determine that , my warranty expired and i dont trust the dealerships , im stuck and dont know what to do :/ , u dont think its a possible flywheel problem?

darkman
06-21-11, 10:33 PM
You can try this for a start:

http://www.theredlion.us/C6%20clutch%20fluid%20DIY.pdf (http://www.theredlion.us/C6%20clutch%20fluid%20DIY.pdf)

wcryan
06-22-11, 02:54 AM
Almost 100% sure its the clutch position sensor. It's the most annoying thing in the world. RPM's usually hang for about 1-2 seconds, not matching with the next gear. It should throw a code soon and then you will 100% know what it is. I think the part is around 30-40$

06BlackV
06-22-11, 04:50 AM
i think its about due for a clutch oil change , and these issues have been going on for about 400 miles or so with no code , will i get one soon?

darkman
06-22-11, 07:29 AM
Almost 100% sure its the clutch position sensor. It's the most annoying thing in the world. RPM's usually hang for about 1-2 seconds, not matching with the next gear. It should throw a code soon and then you will 100% know what it is. I think the part is around 30-40$

As I understand it, the sole purpose of the clutch position sensor (aka clutch switch) is to either enable or disable the starter circuit based on whether the clutch pedal is depressed or not depressed. If this is the case, the clutch switch has no effect on shifting. I do not find a defective clutch switch listed on any of the Service Manual troubleshooting charts for transmission problems.



i think its about due for a clutch oil change , and these issues have been going on for about 400 miles or so with no code , will i get one soon?

The troubleshooting chart for transmission shifting problems begins with verification of clutch operation. Beyond that problems shifting are either caused by issues with the shift linkage or the transmission itself. My guess is that your problem is clutch related. Below is the troubleshooting list for the clutch, by symptom:

The checklist in the Service Manual for Clutch Drag is as follows:
1. Pedal blocked from full travel.
2. Too much travel between pedal and clutch master cylinder or worn pedal bushings.
3. Clutch pedal mounting loose.
4. Linkage at pedal worn or damaged.
5. Clutch master cylinder is seized or binding.
6. Air in clutch hydraulic system.
7. Clutch actuator (slave) cylinder seized or binding.
8. Clutch master cylinder leaking internally.
9. Damaged clutch assembly components. This includes damaged clutch disc, hub, splines, bent clutch disc, bent drive straps, broken or warped pressure plate. [I did not find any thickness specs for the clutch disc.]
10. Excessive side loading on the release bearing.
11. Faulty pilot bearing.
12. Transmission input shaft splines are worn or damaged.
13. Tight or contaminated clutch disc splines.
14. Flywheel housing, engine block to clutch housing, or transmission front case excessively misaligned.
15. Grease or oil contamination on the clutch disc facing.
16. Loose, broken, or faulty motor mounts.


The checklist in the Service Manual for Clutch Slipping, which is identified by increase in RPM without increase in vehicle speed, is as follows:
1. Incorrect pedal height, not allowing the clutch master cylinder to return.
2. Clutch pedal spring is broken or missing.
3. Clutch pedal is binding or sticking.
4. Clutch master cylinder seized or binding.
5. Clutch actuator cylinder seized or binding.
6. Kinked or damaged clutch hose.
7. Grease or oil contaminated clutch disc.
8. Worn, damaged, or improperly resurfaced flywheel.
9. Worn clutch disc facing.
10. Burnt or glazed clutch disc facing.
12. Transmission input shaft splines worn or damaged.

Clutch grabbing differs from clutch drag and is defined in the Service Manual as: The clutch grabs or chatters, or the clutch is unable to release without the vehicle jerking. An abrupt engagement of the clutch.
The checklist in the Service Manual for Clutch Drag is as follows:
1. Grease or oil contamination on the clutch facings from, for example ,rear engine oil seal leakage.
2. Loose, broken, or faulty engine mounts.
3. Clutch pedal sticking.
4. Clutch actuator (slave cylinder) binding.
5. Clutch master cylinder binding.
6. Warped clutch cover.
7. Improper clutch installation.
8. Clutch disc binding on input shaft.
9. Clutch pressure plate damaged.
10. Flywheel improperly machined.
11. Flywheel uneven.



The checklist in the service manual for Clutch Rattle, with clutch engaged or disengaged, is as follows:
1. Idle rattle clutch engaged replace engine flywheel due to faulty springs.
2. Clutch is improperly installed.
3. Clutch disc splines and input shaft splines worn.

Twitch
06-22-11, 08:06 AM
I remember Whisler151 had some problem with a sensor messing up his RPMs. Pretty sure it was under the dash and about 40 bucks. Check his threads.

And deff flush the clutch fluid.

darkman
06-22-11, 08:18 AM
I remember Whisler151 had some problem with a sensor messing up his RPMs. Pretty sure it was under the dash and about 40 bucks. Check his threads.

And deff flush the clutch fluid.

Found it.

http://www.cadillacforums.com/forums/cadillac-forum/t-204100.html

Looks like it was the clutch switch, even though I don't understand it (yet).

wcryan
06-22-11, 12:26 PM
yeah, but you gotta remember. Inside of the clutch position sensor is a spring. If that spring breaks (which mine did). Putting in the clutch vis versa letting it out doesnt do it normal (Which causes funky RPM hangs/drops etc. I lived with this for like 5 months. The cruise control not working is just a GREAT tell tale sign that that sensor is going out or broken.

Jab31169
06-22-11, 12:50 PM
I can 100% confirm that the Clutch position sensor will cause RPM's to hang when switching gears. Just had mine replaced yesterday and it fixed the RPM issue along with bring my cruise control back from the dead.

Jab31169
06-22-11, 12:51 PM
not to mention I can now rev match my down shifts without having to slam the gas pedal.

darkman
06-22-11, 02:31 PM
yeah, but you gotta remember. Inside of the clutch position sensor is a spring. If that spring breaks (which mine did). Putting in the clutch vis versa letting it out doesnt do it normal (Which causes funky RPM hangs/drops etc. I lived with this for like 5 months. The cruise control not working is just a GREAT tell tale sign that that sensor is going out or broken.

The dot that I am unable (so far) to connect is any relationship between RPM and the clutch switch. According to the electrical diagrams the RPM is controlled by the throttle position sensor, the accelerator pedal position sensor and the throttle actuator. These RPM-related components are located on a separate circuit from the clutch switch which shares a circuit with the starter. Based on that, there is no obvious way the clutch switch should affect RPM. Obviously, my conclusion is wrong because there are several instances where the clutch switch clearly did affect RPM levels. I will figure it out eventually.

Jab31169
06-22-11, 03:02 PM
Does the PCM look for the clutch to be engaged/disengaged and somehow relate that to throttle position/response? Just a stab in the dark....

wcryan
06-22-11, 03:13 PM
The dot that I am unable (so far) to connect is any relationship between RPM and the clutch switch. According to the electrical diagrams the RPM is controlled by the throttle position sensor, the accelerator pedal position sensor and the throttle actuator. These RPM-related components are located on a separate circuit from the clutch switch which shares a circuit with the starter. Based on that, there is no obvious way the clutch switch should affect RPM. Obviously, my conclusion is wrong because there are several instances where the clutch switch clearly did affect RPM levels. I will figure it out eventually.

I think that is why the dealership could not figure it out for 6 months. I finally had to tell them myself from people telling me on here and LS1tech. I dont think it has to do so much with it not being mated together in some way with the throttle, but the clutch knowing if it's fully engaged or not from a broken sensor. The sensor has to be good for something that has to do with the clutch. I wasnt totally explained what it was doing, but everyone I have talked to get's the issues; especially the rev matching and hanging throttle. It would be cool to get a low down of why it actually causes these symptoms

darkman
06-22-11, 04:19 PM
I think that is why the dealership could not figure it out for 6 months. I finally had to tell them myself from people telling me on here and LS1tech. I dont think it has to do so much with it not being mated together in some way with the throttle, but the clutch knowing if it's fully engaged or not from a broken sensor. The sensor has to be good for something that has to do with the clutch. I wasnt totally explained what it was doing, but everyone I have talked to get's the issues; especially the rev matching and hanging throttle. It would be cool to get a low down of why it actually causes these symptoms

One common denominator between these circuits, that is not delineated on the electrical diagrams is the ECM itself. So, it is possible, I suppose that if the ECM does not detect the clutch switch operation that it "expects" that it does something different. Perhaps a tuner could chime in on that possibility.

wcryan
06-22-11, 04:34 PM
One common denominator between these circuits, that is not delineated on the electrical diagrams is the ECM itself. So, it is possible, I suppose that if the ECM does not detect the clutch switch operation that it "expects" that it does something different. Perhaps a tuner could chime in on that possibility.

If that's the case. Maybe that's why everytime I disconnected and reconnected my battery for an hour or so, it would go away. I think were getting somewhere

06BlackV
06-22-11, 06:00 PM
thanks everyone for ur input , unfortunately its a guessing game for me , my cruise control does work so with that being said , im assuming the clutch position sensor is fine , i have no code yet , ive beat up my boxing bag at home trying to figure this out without relying on the ripoffs at dealerships and local shops :/

darkman
06-22-11, 06:17 PM
thanks everyone for ur input , unfortunately its a guessing game for me , my cruise control does work so with that being said , im assuming the clutch position sensor is fine , i have no code yet , ive beat up my boxing bag at home trying to figure this out without relying on the ripoffs at dealerships and local shops :/

Well, one simple thing to try would be to disconnect the battery for 30 minutes to clear the ECM, and see whether the symptom goes away temporarily.

RADEoN
06-22-11, 07:31 PM
i'm skeptical that it's the CPS, to be honest. I really think it's a clutch or even hydraulic issue.

I could be wrong, though.

wcryan
06-22-11, 08:40 PM
Try the battery method and get back to us...... Unhook it for about 30-40 minutes and hook it back up and go take it for a drive

darkman
06-22-11, 08:48 PM
i'm skeptical that it's the CPS, to be honest. I really think it's a clutch or even hydraulic issue.

I could be wrong, though.

Hang around - you may be right. Diagnosing over the internet is always a crap shoot.

06BlackV
06-22-11, 10:26 PM
i work the graveyard shift, but first thing in the morning , i will unhook the battery and let u guys know what happends ,, thanks fellas

wcryan
06-22-11, 10:53 PM
I'll cross my fingers for ya

06BlackV
06-22-11, 11:18 PM
ok i had time to disconnect the battery here at work , i connected it , then on my break , i drove it and no more RPM issue:) , but the clutch still having hard time with the downshift so i checked the clutch reservoir and its about 3/4 of an inch from the max level , its low, could this be the problem

wcryan
06-23-11, 12:38 AM
replay in words to me what it is doing during downshifts again?

06BlackV
06-23-11, 03:16 AM
up shifting is very good , no problems, when im at speeds about 35 mph or higher and i want to down shift , it doesnt want to go in any gears , when it slows below 35mph , i dont have this problem down shifting

mstrjon32
06-23-11, 03:41 AM
I was just reading this thread and it struck a disturbing chord with me. My SES is on (don't have a code scanner to read the code, yet), the cruise control won't engage, and I've noticed recently that I feel like it's impossible to get a smooth rev-match. After reading this I feel like I'm going to finally get the code pulled and it's going to say CPS.

I need to get a scanner and figure out what's going on with this code.

wcryan
06-23-11, 04:33 AM
the cruise control is the tell tale sign that it is your clutch position sensor. Also the when it's hard to rev match going up and down in gears..... Good thing it's a 40$ part

06BlackV
06-23-11, 08:43 PM
i just found out that when it is cold , the rpms and downshifting works better than when it warms up , and my cruise control does work .,

darkman
06-23-11, 09:11 PM
Have you done anything about the clutch fluid yet? If not, if could still be factor even if there is another problem at the same time.

06BlackV
06-23-11, 09:12 PM
what kind of fluid do i need for the clutch? and do i fill to the max level ? because i heard fluid rises when it heats up

wcryan
06-23-11, 09:15 PM
id say 3/4th's

darkman
06-23-11, 09:20 PM
Look at Post #4 - there is a link to a "how to". It is just a quick fix for a full flush and bleed procedure, but it should be good enough to see if fluid is an issue. You use brake fluid - DOT 3 or DOT 4 (better), and make sure it is fresh bottle as brake fluid attracts water once opened. Finally, it should be full since its a small reservoir anyway.

06BlackV
06-23-11, 10:06 PM
ok thats sounds like a start, can i top it off with fresh fluid just to see if it helps , and if so , change the fluid after ?

darkman
06-23-11, 10:43 PM
Periodically (at least every 24 months) the clutch fluid needs to be changed by a bleeding and flush operation just like your brake system. That is a somewhat more difficult procedure, but more importantly it can be a little risky for the do-it-yourselfer because the bleeder valve is located on the side of bell housing and where it can fall inside. The remedy can require removing the transmission. That is why I suggested the "quick-fix" as a start.

06BlackV
06-24-11, 07:57 AM
interesting , as i was driving home from work , (like before) im having a hard time downshifting , so i tried to down shift from 5-4 , and while doing so i hit the gas at the same time and it popped right into gear ,,, wtf?

06BlackV
06-24-11, 08:00 AM
the same thing with the other gears, a little gas while engaging the clutch and my downshifting works ,,, could it be shift forks?

RADEoN
06-24-11, 08:12 AM
that's because things lined up and made it go in gear, it's the same thing if you were to pull out in first, pull it out of gear, and hold it into 2nd, and it'll eventually pop in normally. when the RPM's are just right, you can slide it in gear.

The fact that you just told us that makes me really think it's clutch related.

oh, and "topping it off" is a waste of time. you need to bleed the clutch to let any trapped air and all bad/tired fluid escape.

where do you live?

06BlackV
06-24-11, 11:06 AM
ive had that feeling all along radeon , because my cruise control works , so my cps should be ok , and i live in detroit michigan what about u?

RADEoN
06-24-11, 01:11 PM
oh i live in pittsburgh, i was gonna help you out if you were close.

06BlackV
06-27-11, 10:47 AM
i appreciate it radeon , im in Michigan , i took the car to a local known trans shop and they say its my synchros , they say my clutch is fine , but that was only by test driving the car, so with their opinion in mind , i took the car to don massey cadillac close to my house and im going to have them analyze and check it out and see what they find ,,,, hopefully they can dissect the problem , ill keep everyone posted. also, i should post a new thread but when the rpms rev down between shifts/and around 2k-2300 rpms i get vibrations , motor mounts? trans mounts?

RADEoN
07-01-11, 07:22 PM
synchros would be grinding