Vibration after transmission swap
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
Melting Slicks
Joined: Dec 2009
Posts: 3,220
Likes: 651
From: Thunder Bay
Sounds like your problem is in the flywheel, clutch or pressure plate. Now try revving the engine while the car is stationary, in gear, and clutch depressed. if the vibration is still present you have eliminated the clutch disc and transmission as possible problems ( because they aren't turning). That only leaves the flywheel and pressure plate as potential problems. If the vibration is gone, then it has to be clutch disc, or transmission. I don't think its a driveline problem because that would be speed dependent, not RPM.
Instructor
Joined: Oct 2011
Posts: 133
Likes: 1
From: Edmonton Alberta
I agree with the above comment.
Having just replaced my trans mount with a poly one (rubber one was distorting from age) I became concerned about all the talk on driveline angles and began reading all I could on the subject.
Assuming the mount you got had a height difference that was significant and threw you outside of the optimal angle, the literature I read suggested that it would induce harmonic vibration - not a consistent one throughout the entire rpm range.
Could it be part of the problem? Yes, but I don't think it would be solely repsonsible for the significant symptoms you are suggesting.
Then again I haven't lived through the problem (trans. mount) myself to be able to comment directly upon as it seems some others here have.
Having just replaced my trans mount with a poly one (rubber one was distorting from age) I became concerned about all the talk on driveline angles and began reading all I could on the subject.
Assuming the mount you got had a height difference that was significant and threw you outside of the optimal angle, the literature I read suggested that it would induce harmonic vibration - not a consistent one throughout the entire rpm range.
Could it be part of the problem? Yes, but I don't think it would be solely repsonsible for the significant symptoms you are suggesting.
Then again I haven't lived through the problem (trans. mount) myself to be able to comment directly upon as it seems some others here have.
Thread Starter
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
The drive home was much more enjoyable with the rubber trans mount. There's still the vibration around 3000 rpm, but its not as noticeable.
I'm wondering if the pressure plate was supposed to be indexed, I didn't see any paint dots on it or anything. If American Powertrain would call me back I could ask them. If the flywheel run out is ok, I can always try to turn the pressure plate 180* and see if it helps.
I'm wondering if the pressure plate was supposed to be indexed, I didn't see any paint dots on it or anything. If American Powertrain would call me back I could ask them. If the flywheel run out is ok, I can always try to turn the pressure plate 180* and see if it helps.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
The drive home was much more enjoyable with the rubber trans mount. There's still the vibration around 3000 rpm, but its not as noticeable.
I'm wondering if the pressure plate was supposed to be indexed, I didn't see any paint dots on it or anything. If American Powertrain would call me back I could ask them. If the flywheel run out is ok, I can always try to turn the pressure plate 180* and see if it helps.
I'm wondering if the pressure plate was supposed to be indexed, I didn't see any paint dots on it or anything. If American Powertrain would call me back I could ask them. If the flywheel run out is ok, I can always try to turn the pressure plate 180* and see if it helps.
pressure plate is neutral.. and the bolt pattern i believe only lets it go on one way anyway....
did you read my thread on drive shaft alignment i posted for you?
just do not believe it is a new flywheel...
Thread Starter
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
I'll have to do it on Monday if its nice enough to drive the car to work.The PP should fit on the flywheel in 6 different positions.
The biggest vibration is definitely in the engine, and doesn't change when I depress the clutch.
Last edited by qwank; Apr 14, 2012 at 10:02 PM.
Instructor
Joined: Oct 2011
Posts: 133
Likes: 1
From: Edmonton Alberta
"The drive home was much more enjoyable with the rubber trans mount. "
Just a thought here, while you are trying to diagnose the problem which may or may not be related to the trans mount, keep in mind that depending on which brand/model of poly mount you used you may have simply dampened the vibration which is still there by switching over to the rubber mount. In other words it may feel less severe but it is possible the source and cause of the problem still exists but it has been dampened more and therefore less noticeable.
I recently bought a shorter version of a poly mount from E.S. which also happens to be made of a much softer polyurethane than their other ones and find that it is almost identical in "firmness" to the stock rubber ones.
Just a thought here, while you are trying to diagnose the problem which may or may not be related to the trans mount, keep in mind that depending on which brand/model of poly mount you used you may have simply dampened the vibration which is still there by switching over to the rubber mount. In other words it may feel less severe but it is possible the source and cause of the problem still exists but it has been dampened more and therefore less noticeable.
I recently bought a shorter version of a poly mount from E.S. which also happens to be made of a much softer polyurethane than their other ones and find that it is almost identical in "firmness" to the stock rubber ones.
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Thread Starter
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
yes, the rubber mount just dampened the vibration for sure. There's still a problem. I still think its flywheel/pressure plate related.
I installed a Richmond 5 speed, I did order the flywheel, pressure plate and hydraulic linkage through the group buy though. It took about 4 weeks for all my parts to arrive, the flywheel was drop shipped from the manufacturer.
I installed a Richmond 5 speed, I did order the flywheel, pressure plate and hydraulic linkage through the group buy though. It took about 4 weeks for all my parts to arrive, the flywheel was drop shipped from the manufacturer.
Melting Slicks
Joined: Jul 2006
Posts: 2,373
Likes: 6
From: Baltimore MD
yes, the rubber mount just dampened the vibration for sure. There's still a problem. I still think its flywheel/pressure plate related.
I installed a Richmond 5 speed, I did order the flywheel, pressure plate and hydraulic linkage through the group buy though. It took about 4 weeks for all my parts to arrive, the flywheel was drop shipped from the manufacturer.
I installed a Richmond 5 speed, I did order the flywheel, pressure plate and hydraulic linkage through the group buy though. It took about 4 weeks for all my parts to arrive, the flywheel was drop shipped from the manufacturer.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
Glad the mount helped. $10 improvements are always nice
Yup. If you pull it out have it balanced even if they say it already was probably run you $25-$50. THen have them mark the clocking of the pieces. It will be smooth as silk after that. Chasing this stuff is a bitch when you have to pull/install the trans back to back lol. BTDT.
Keep at it, real sweet deal when its right.
The PP should fit on the flywheel in 6 different positions.
Keep at it, real sweet deal when its right.
Thread Starter
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
$6.75 
Yup, my best option now seems to be to pull it apart and bring the assembly down to the machine shop and have it balanced. a pain in the butt, but it will be worth it.
Pulling the trans isn't a big deal, as long as I don't have to pull the pedal assembly out ever again
Yup, my best option now seems to be to pull it apart and bring the assembly down to the machine shop and have it balanced. a pain in the butt, but it will be worth it.
Pulling the trans isn't a big deal, as long as I don't have to pull the pedal assembly out ever again
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Yup. If you pull it out have it balanced even if they say it already was probably run you $25-$50. THen have them mark the clocking of the pieces. It will be smooth as silk after that. Chasing this stuff is a bitch when you have to pull/install the trans back to back lol. BTDT.
Keep at it, real sweet deal when its right.
That is your problem. Neutral balanced flywheels will always have some holes drilled in it on the edge to balance it. Castings will never be 100% out of the mold.
Thread Starter
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
So I wonder if American Powertrain ever gets back to me, If they would just exchange it, or if I'll be better off just getting it balanced myself.
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
Take your flywheel and pressure plate (with new mounting bolts) to the automotive machine shop and have them neutral-balanced together as a unit.
They will mark the married location either by paint stripe or punch marks.
I'm surprised so many folks that assemble engines just slap the parts together without checking clearances or having all the reciprocating pieces balanced. Seems like sloppy workmanship.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
Let's see if I understand your thinking. Are you saying if American Powertrain exchanged flywheels, you'd install the new one without balancing just because they said it was OK? Bad idea.
Take your flywheel and pressure plate (with new mounting bolts) to the automotive machine shop and have them neutral-balanced together as a unit.
They will mark the married location either by paint stripe or punch marks.
I'm surprised so many folks that assemble engines just slap the parts together without checking clearances or having all the reciprocating pieces balanced. Seems like sloppy workmanship.
Take your flywheel and pressure plate (with new mounting bolts) to the automotive machine shop and have them neutral-balanced together as a unit.
They will mark the married location either by paint stripe or punch marks.
I'm surprised so many folks that assemble engines just slap the parts together without checking clearances or having all the reciprocating pieces balanced. Seems like sloppy workmanship.
Thread Starter
Le Mans Master
Joined: Feb 2011
Posts: 5,943
Likes: 61
From: Southern NH
So I took the transmission back out and measured the flywheel run out. I had .015" runout.
So the question is, would this cause the vibration, or is it just the reason for the clutch chatter?
oh, and shortly after measuring the runout, my dial indicator fell off my tool box and broke
So the question is, would this cause the vibration, or is it just the reason for the clutch chatter?
oh, and shortly after measuring the runout, my dial indicator fell off my tool box and broke
Last edited by qwank; Apr 25, 2012 at 10:35 PM.