Clutch pedal vibration, SBC DD

[hasselbach]

Installed my DD SBC 3600# street unit a few weeks ago in my 05. The stock slave unit wasn't going to last, so I put in a SBC 94-97 unit.



Now I notice if I hold down the pedal and rev the motor past 2500, I feel a strong vibration in the pedal, and same thing happens when I shift over 2500 rpms, a weird vibration comes though the pedal.



anyone else?



I'm thinking that the unsprung hub is causing the vibration from the transmission to come though the throwout bearing and effectivily though the pedal.

 

[jwilliams3]

Tim,

Its not transmission vibration.

I think you are pushing the fingers past their effective point.



Once the clutch wears in a bit this will go away.

 

[hasselbach]

Tim,

Its not transmission vibration.

I think you are pushing the fingers past their effective point.



Once the clutch wears in a bit this will go away.

If you were sitting in my truck with your foot on the pedal, you would know its vibration.



It does it regardless of pedal movement or depth of the pedal position.



I've asked Peter at SBC about this and I wasn't given a response. I'm not too happy about it either. It makes it very uncomfortable to shift now and I am to the point I wish I didn't put in the DD clutch afterall.

 

[JCleary]

If you were sitting in my truck with your foot on the pedal, you would know its vibration.



It does it regardless of pedal movement or depth of the pedal position.



I've asked Peter at SBC about this and I wasn't given a response. I'm not too happy about it either. It makes it very uncomfortable to shift now and I am to the point I wish I didn't put in the DD clutch afterall.

That's strange. I only feel a vibe when I push the clutch in too far and something rubs the fingers on the clutch. Any other pedal position and it's fine, although you hear the center plate rattle a bit.

 

[hasselbach]

That's strange. I only feel a vibe when I push the clutch in too far and something rubs the fingers on the clutch. Any other pedal position and it's fine, although you hear the center plate rattle a bit.

yeah, peter did tell me that your situation is different than mine. Mine vibrates anywhere in the pedal throw. Heck, YOu can just push the pedal 1 inch, and rev the motor, and when it hits say 2000 rpm, the pedal starts to buzz. Wonder if I have a bad throwout bearing?

 

[RDusch]

Mine is doing the same thing, mine is about 2100+ , every time i shift at high rpm i get a buzzing vibration in the pedal, it drives me crazy.

Mine is also very hard to shift.

 

[hasselbach]

Mine is doing the same thing, mine is about 2100+ , every time i shift at high rpm i get a buzzing vibration in the pedal, it drives me crazy.

Mine is also very hard to shift.

I wish SBC told me this was a side effect.



Thanks for the information, I was getting worried mine was the only one.



To all with this problem, I think we need to tell Peter at SBC that this is a problem. I don't like the feel of the pedal when I shift in the upper RPM's, and after paying $1750 bucks for the clutch, it should be perfect IMO. Plus, I have a shudder that I thought wasn't supposed to happen with the street set up.

 

[JCleary]

... after paying $1750 bucks for the clutch, it should be perfect IMO. Plus, I have a shudder that I thought wasn't supposed to happen with the street set up.

ditto on both counts

 

[jwilliams3]

Guys... .

When you get into performance arena you are going to have to give up the niceties and friendlyness of your off the shelf truck.



Dual Discs by nature are going to wear on your syncronizers at an accelerated rate and cause your shifting to be hampered or present challenges.



I might as well talk to the wall..... :-laf

 

[Turbo Tim 1]

If you give it a touch of throttle when taking off the shutter will go away.

 

[hasselbach]

Guys... .

When you get into performance arena you are going to have to give up the niceties and friendlyness of your off the shelf truck.



Dual Discs by nature are going to wear on your syncronizers at an accelerated rate and cause your shifting to be hampered or present challenges.



I might as well talk to the wall..... :-laf

I understand the issue of Hot Rodding, and the effects on drivability...



However, this buzzing in the pedal over 2000 rpm is unexplanable and shouldn't be there. I was also told that the Street DD set up wouldn't shudder, but it does.



That's my concern right now.

 

[hasselbach]

If you give it a touch of throttle when taking off the shutter will go away.

No it doesn't, in fact it gets worse.

 

[JasonCzerak]

Tim,

Its not transmission vibration.

I think you are pushing the fingers past their effective point.



Once the clutch wears in a bit this will go away.

My clutch is still perfectly stock. I have the same vibration you guys are talking about in the peddle.



It started to happen once night after a really hard 4x4, 2300rpm-ish launch. This was one of them picture perfect launches and rowing of the gears to win a nice race too. So, I wasn't nice on anything for that run.



Think I could of bent or cracked something?



This has been like this since mid summer and 15,000 - 20,000 miles or more I'm sure.

 

[RustyJC]

Since you're talking about "buzzing", this probably isn't the case, but here's something to watch out for.



The shop that installed my SBC CON OFE farmed out the flywheel refinishing, and the shop that did the work didn't index the flywheel on the crank flange surface when setting it up in the grinder. When I got the truck back, it had a noticeable first order (at engine RPM) vibration that could be felt through the floorboard and through the clutch pedal while shifting.



When I took the truck back to the shop, there were discussions between the shop, Peter, me, the machine shop, etc. Ultimately, they pulled the transmission and clutch and took a runout on the flywheel surface (something they should have done the first time) and came up with 0. 045". After pulling the flywheel and having it ground by a shop that knew what they were doing and reassembling the truck, everything was fine.



Rusty

 

[hasselbach]

Since you're talking about "buzzing", this probably isn't the case, but here's something to watch out for.



The shop that installed my SBC CON OFE farmed out the flywheel refinishing, and the shop that did the work didn't index the flywheel on the crank flange surface when setting it up in the grinder. When I got the truck back, it had a noticeable first order (at engine RPM) vibration that could be felt through the floorboard and through the clutch pedal while shifting.



When I took the truck back to the shop, there were discussions between the shop, Peter, me, the machine shop, etc. Ultimately, they pulled the transmission and clutch and took a runout on the flywheel surface (something they should have done the first time) and came up with 0. 045". After pulling the flywheel and having it ground by a shop that knew what they were doing and reassembling the truck, everything was fine.



Rusty

Oh wonderful... now something else to worry about.



Actually I'm not flaming SBC (even though I got a strong PM yesterday from Peter saying I was), and I was vrey impressed with the unit.



I'm just trying to figure this out, and I really don't want to pull the whole unit again for obvious reasons.



I don't feel any vibration when the truck is reved up, which is good meaning my balance is okay. Its just very annoying shifting when the r's are over say 2000 and hitting the pedal, it almost feels like there is foam or bubbles in the servo when you push on the pedal. Its an odd feeling and my take is some type of unevenness in the pressure plate or throwout bearing is causing the feed back to the pedal.



All input is appreciated.



Thanks

 

[JFaulkner]

You guys are amazing! jwilliams3 is right, If your truck was suppost to have a DD clutch; it would have came that way from the factory. You’re asking certain parts to do things that they are not designed for. You can't have your cake and eat it too. My g56 shifted fine and was quiet stock. However when I installed the DD it ruined the slave, got extremely noisy, harder to shift, slightly and I do mean slightly grabby and yes the pedal does vibrate. The trade off for all this was the fact that it holds the power, if your that dissatisfied with it sell it and put the stock one back in.



I'm not trying to be mean but come on guys don't you think your being a little picky?

 

[hasselbach]

You guys are amazing! jwilliams3 is right, If your truck was suppost to have a DD clutch; it would have came that way from the factory. You’re asking certain parts to do things that they are not designed for. You can't have your cake and eat it too. My g56 shifted fine and was quiet stock. However when I installed the DD it ruined the slave, got extremely noisy, harder to shift, slightly and I do mean slightly grabby and yes the pedal does vibrate. The trade off for all this was the fact that it holds the power, if your that dissatisfied with it sell it and put the stock one back in.



I'm not trying to be mean but come on guys don't you think your being a little picky?

So why do you think the pedal vibrates then?



I'm not whining, I just can't figure out the vibration and where it is coming from.



And if I was told it was grabby, I would have bought the Con fe for 900 less and lived with the grabby engagement and saved a lot of cash. I was told and have read marketing releases that the street DD was smooth engagement without the grabbing that other hi perf units demonstrate.

 

[JasonCzerak]

Since you're talking about "buzzing", this probably isn't the case, but here's something to watch out for.



The shop that installed my SBC CON OFE farmed out the flywheel refinishing, and the shop that did the work didn't index the flywheel on the crank flange surface when setting it up in the grinder. When I got the truck back, it had a noticeable first order (at engine RPM) vibration that could be felt through the floorboard and through the clutch pedal while shifting.



When I took the truck back to the shop, there were discussions between the shop, Peter, me, the machine shop, etc. Ultimately, they pulled the transmission and clutch and took a runout on the flywheel surface (something they should have done the first time) and came up with 0. 045". After pulling the flywheel and having it ground by a shop that knew what they were doing and reassembling the truck, everything was fine.



Rusty

I'm about to do this wit my 3gen. I plan on doing the machine work on a saturday with a napa store. SpicyJam had his done at a napa some years ago and has no complains that he told me of.



So, just to be anal about how it's done. What questions do I ask the tech performing the work about tolerances? what measurments should I look for before installing it? and special tools?



When I did my jeep's flywheel, I just dropped it off and got it back and things worked. I hope I can do with with the truck, but I wish not to remove this trans twice over something like this.

 

[South Bend Clutch]

My feeling is that if you are getting a vibration in the pedal and also experiencing chatter on takeoff from a fiber (street) DD clutch that it may be the fingers of the pressure plate may be uneven. This could also cause a heavier pedal then normal. I am sure hasselbach did a fine job with the installation. Sometimes when unbolting the clutch from the flywheel when removed from the shipping box and bolting it back in during install... if the bolts are not gradually backed out and put back in with 1/4 turns in a star pattern it could cause the levers to end up uneven as an end result.



First and foremost... hasselbach, I want you happy. If we need to switch out the clutch, not a problem. If we need to compensate some on the labor, not a problem.



Peter

 

[hasselbach]

My feeling is that if you are getting a vibration in the pedal and also experiencing chatter on takeoff from a fiber (street) DD clutch that it may be the fingers of the pressure plate may be uneven. This could also cause a heavier pedal then normal. I am sure hasselbach did a fine job with the installation. Sometimes when unbolting the clutch from the flywheel when removed from the shipping box and bolting it back in during install... if the bolts are not gradually backed out and put back in with 1/4 turns in a star pattern it could cause the levers to end up uneven as an end result.



First and foremost... hasselbach, I want you happy. If we need to switch out the clutch, not a problem. If we need to compensate some on the labor, not a problem.



Peter

Thanks Peter, I know you are very customer service oriented.



And in no way was my post to flame SBC. You guys build a nice product.



I did carefully remove and tighten the pressure plate as you mentioned, but your thoughts do make sense being the pressure plate is crooked or uneven. That's the information I was looking for to figure this out. The vibration I believe isn't or shouldn't be a side effect of having a DD set up, but thinking outloud about the fingers not being square to the throwout bearing, sounds reasonable.



What parts will I have to swap out? Just the pressure plate?



Thanks again Peter.



Tim