Clutch issues - can't diagnose, video included

[Big Dan]

 

Couldn't find anything on this. First off, ax15 swapped in and has run fine for a few years. I kept a new ba10/5 pressure plate and clutch in (out of, at the time, ignorance). It's been fine.

Anyway, this issue started about a week ago. Once in gear, no problems at all. Any time the clutch pedal is pushed in, and gas is applied, the engine stutters. This makes it difficult to rev match or get up a hill, from a stop.

 

Is this a pilot bearing, throw out bearing or something else?

 

http://nighthawk101.com/video/jeep/YouCut_20211030_125455044.mp4

 

edit - video link fixed

 

 

 

[howeitsdone]

Following out of curiosity. I almost wonder if the bearing or flywheel itself could cause this.

What happens if you are stopped, put it in gear, and slowly let the clutch out? Does it just die like it should?

[Big Dan]

On level terrain, I can let out of the clutch, slowly, without killing the vehicle. But, yes, if I dump the clutch, it will die as it should.

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[Andy in Pa]

I don't hear any noise in the video, but are you hearing anything that sounds loose?  Also, do the rpms change at all at idle with pushing the clutch in?  Even a little jump?  You may want to to take a good look at the wiring under the dash by the clutch pedal/linkage.  Maybe something is getting rubbed or pinched when the clutch gets pushed in.

[Big Dan]

No, nothing sounds loose and RPMs, at idle, are the same with clutch pedal in or out.  The only time the issue occurs is clutch pedal depressed (in neutral or in gear) and gas applied.  Once the vehicle is moving, and in gear, there seems to be no symptoms.  However, even when moving, if I push the clutch in and hit the gas, the engine will stutter.

 

I'll be taking everything apart soon.  But, I was hoping to get an idea of what it was, before hand, so I could have parts ready.

[Ωhm]

So engine sputters only under a no-load condition (gas being applied), yet run fine under load condition (gas being applied). Suspect MAP sensor.

[Big Dan]

I'll give it a look and report back.

Specifically, it's no load (with gas applied) only with the clutch pedal depressed. Unless I'm mistaken, the MAP sensor wouldnt have a clue if the clutch pedal was depressed or not.

[Ωhm]

7 hours ago, Big Dan said:

Unless I'm mistaken, the MAP sensor wouldnt have a clue if the clutch pedal was depressed or not.

 

Yes your correct about the MAP sensor and the clutch pedal, but MAP does sense engine load. So sputter only occurs with clutch pedal depressed (with gas applied) and not when the transmission is in neutral, clutch pedal UP?

[Big Dan]

That is correct

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[Ωhm]

Understood.

 

Don't see how this could tie in either, but is vehicle equipped with Cruise Control (CC)? If so, should have a clutch switch.

[Big Dan]

It was. However, I removed that some time back. So the clutch switch, and related stuff, is out of the vehicle.

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[eaglescout526]

How’s the TPS? Could be misadjusted and dumping more fuel in than the engine can adjust for. 

[Andy in Pa]

You know, I am starting to wonder if the flywheel is loose or cracked or something.  If the relationship with the CPS somehow changes with clutch in/out, it would affect rpm at high levels.  With the clutch pushed in, it unloads the flywheel and it spins more freely.  Or maybe the CPS is loose?  It sounds like you were just in there working on it not too long ago.

[Big Dan]

I'll take everything apart soon, and check it out. I haven't been in the transmission for a few years.

I had an issue that was weird, with the clutch, a short time ago. But, it ended up being a grounding issue. And the engine would ground when I pushed the clutch in. However, I did not have to remove anything, transmission related, to fix

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[Big Dan]

How’s the TPS? Could be misadjusted and dumping more fuel in than the engine can adjust for. 

I'll double check. Should be set correctly, but, I suppose, that could always come out of whack. However, I would think that would effect fuel "dumping" both clutch in and out. And, not just one scenario.

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[eaglescout526]

Not necessarily. I’ll sometimes get this issue where I’ll be making a left hand turn and I want to get going and the engine will kinda stumble on itself until it finally gets the fact it needs to go. 

[Big Dan]

I'll check cps and map, this evening, and report back. If no issues there, I'll begin the transmission removal process. Not looking forward to it.

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[Big Dan]

I got busier than I thought I would be. Hopefully tomorrow night (Thursday), I can get out in the shop and provide an update on the sensors.

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[Big Dan]

It took a little while. Sensors tested out.
Took the transmission out and was hoping to see something visibly broken, just so I could narrow this down.
Unfortunately, from that perspective, everything looks good. Throwout bearing is still smooth. Pilot bearing looks good. But, I'll take the clutch off to confirm.

I did, however, notice that both top bolts, on the transmission, and the 3/8 bolt on the drivers side were missing. I suppose I didn't torque them down properly. Perhaps the transmission was working loose and that was the issue. I didn't see a visible gap, but, it's a theory.

I'm going to go ahead and replace the clutch/pressure plate since I'm in here, and, because it's the part for a ba 10/5.

I'm open to suggestions as to causes. Would a small transmission separation be possible even with both bottom bolts and the drivers side bolt present?



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[cruiser54]

You beat me to it. Loose engine bolts can cause just such issues. 

[Big Dan]

New clutch, pressure plate and throwout bearing installed. I'm short on time due to family obligations, so, I havent hooked up the clutch hydraulics yet. However, started engine, in gear and output shaft end turns. So, that's all good to go. No weird noises or anything.

So, will hook up clutch hydraulics, tonight, and see if I will be sad or not.

Ps - holy F. Getting the trans back in is a nightmare

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[Big Dan]

Clutch hydraulics hooked back up...and everything works fine.  That would, almost 100%, make the the missing transmission bolts (and subsequent partial tranny separation) the culprit.  I had a bag full of 3/8-16 X 1 1/2" .  As I read that was the appropriate size/length for the e12 bolts, I went ahead and put those in.  Different threads mention 3/8” x 16 x 1 7/8” as the "other" upper bolts.  I don't have any of those on hand, so I'll need to source at least one. 

 

However, I can't figure this out - Are the other 3/8" bolts supposed to have a nut like the 7/16" ones do?  If the are supposed to have one, that would explain the missing driver's side 3/8 bolt.  Please let me know either way.

 

I also need to source a starter bolt.  I am missing the lower one.  I have read that it is, also, supposed to be 3/8-16 X 1 1/2".  I'm not out at the shop now, but, Ill confirm that in a few days, when I return home.  If that is NOT the appropriate bolt, if someone can let me know it would be greatly appreciated so I can go on and have it on hand.

 

FINALLY - I don't know if it was the transmission partially separating OR the fact that the correct pressure plate is now present...but the clutch pedal is feather light.  It still begins to engage/disengage at half travel, but there seems to be so much less resistance than before.  It will take a little bit to get used to.

[cruiser54]

Glad to hear it. 

[Big Dan]

Question for whoever reads this. This is in relation to my earlier comment about a feathery light clutch pedal.

How stiff does your clutch pedal feel?

Prior to the pressure plate, throw out bearing replacement, mine felt like any normal jeep. Now, while the clutch still engages at about half pedal travel, there is almost no resistance, in the pedal, it seems. It is the lightest clutch I've had experience with.
 
EDIT - for reference, relatively new pre-bled Mopar Master/slave cylinder combo utilized.  It was on for, perhaps, 100 miles prior to the clutch change. Clutch felt normal prior to work on transmission.  I state that to, potentially, rule out air in the line.
 

[zomeizter]

On 11/23/2021 at 7:32 PM, Big Dan said:

Question for whoever reads this. This is in relation to my earlier comment about a feathery light clutch pedal.

How stiff does your clutch pedal feel?

Prior to the pressure plate, throw out bearing replacement, mine felt like any normal jeep. Now, while the clutch still engages at about half pedal travel, there is almost no resistance, in the pedal, it seems. It is the lightest clutch I've had experience with.
 
EDIT - for reference, relatively new pre-bled Mopar Master/slave cylinder combo utilized.  It was on for, perhaps, 100 miles prior to the clutch change. Clutch felt normal prior to work on transmission.  I state that to, potentially, rule out air in the line.
 
 

Clutch pedal "feel" should not be stiff, it should be firm but smooth and the pressure plate disengagement/engagement at about the pedal travel half-way mark is ideal.