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Dietzsch_Racing25

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Vibrations
02/02/16 at 7:24pm

Hi Guys,

I need some help. I am having some vibration issues. I will give you a bit of history... hopefully some of you will have suggestions.

Since 2005 I have run a powerglide in first gear. I have always been told that running in high gear is better because you're not going through a gear reduction in the trans.

In 2013 I bit the bullet and bought a 6.33 gear for Perris. I had a mild vibration at about 5500-6000 rpm. I figured it was my driveshaft and took it to have it balanced. I found out at the next race that it didn't fix my vibration so I went back to my 3.50 rear gear and first gear. The vibration went away.

Later that year, I went to orange show and installed a 7.33 so I could run in high gear. I had the same vibration. Since then I have been running in first gear.

Until two races ago. I put in a new powerglide and a new drive shaft and my 6.33. I had the same vibration. I put a new trans mount in for the second race and vibration got worse.

Does anyone have any idea what the cause could be. It only happens in high gear when the drive shaft is spinning at same rpm as the engine.

I have tried two different transmissions, two different rear gears, two different drive shafts and two different engines. I don't know what it could be that would cause the vibration in high gear but not in low.

People have suggested axles and tires but those are both turning at the same speed regardless of what gear I am in.

Any suggestions would be greatly appreciated.

CD

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DaveBauerSC6 LMR God Offline GATOR Eng 661-833-6127 Posts: 603 Bakersfield, CA	Re: Vibrations Reply #1 - 02/02/16 at 10:48pm Who built each tranny?
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Dietzsch_Racing25 LMR God Offline Posts: 995	Re: Vibrations Reply #2 - 02/03/16 at 7:26am Hi Dave, Lukes Transmission in Riverside (red 98 car). He builds the transmissions for a bunch of guys down here. CD
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dirtmopar44 LMR Member Offline Posts: 212	Re: Vibrations Reply #3 - 02/03/16 at 7:47pm Sounds like the exact same problem I had. In my case I had to much pinion angle (pinion down at static ride height) but it sure looked OK and I thought there was no way it had to much angle. As I moved it up the vibration went away. You can get wedges to try before you cut the purches loose.
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Dietzsch_Racing25 LMR God Offline Posts: 995	Re: Vibrations Reply #4 - 02/04/16 at 8:05am Thanks Mike, Were you going through u-joints(I am not)? Do you know what angle you started with and what ended up getting rid of the vibration? CD
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dirtmopar44 LMR Member Offline Posts: 212	Re: Vibrations Reply #5 - 02/04/16 at 10:35am I don't remember what angle I ended up with. I had the clamp on purches so I just moved a little at a time until it went away. Don't get caught up in the more pinion angle = more forward bite.
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Dietzsch_Racing25 LMR God Offline Posts: 995	Re: Vibrations Reply #6 - 02/04/16 at 11:55am I haven't played with pinion angle at all. It has been what it has been since '05. I haven't had problems with u-joints and I was under the impression that I would be running through them on a regular basis if my angle was excessive.
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Chris Swank LMR Rookie Offline Posts: 38 Bakersfield	Re: Vibrations Reply #7 - 02/05/16 at 10:33pm this might help http://www.ringpinion.com/technicalhelp/contentframe.aspx?FilePath=%7e%2fContent...
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Dietzsch_Racing25 LMR God Offline Posts: 995	Re: Vibrations Reply #8 - 02/09/16 at 9:56am Once I get everything back together I will take a look at my angles. Thanks Chris. CD
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