[Tintop55]

howdy, I own a 68 El Camino,slightly built SB 350, M20 Muncie, 390 12 bolt possi rear.Tires are BFG 235/r15 front,275r15 rear,anyways at apx 66+ MPH I start gettin a pretty good vibration goin,,not so much the car, but the hurst shifter is starting to rattle a bit, and gets worse as I approch 70 mph,apx 3,100 rpm. If I take it up to say 80 or 85+ it seems to settle down and get quiet,(smooth) again. I was thinkin of going to a higher gear ratio on the rear, say 3:55 or 3:31 to try to lower the RPM, but Im really starting to wonder if that IS the cure? Or does anyone have some suggestions on how I CAN try to get rid of the (BAD VIBES)???........Thanks Tintop55

 

[Tedster]

Have you done any work with the tranny or rearend lately? Did it just start out of nowhere, or has it gotten progressively worse? My guess is that the tranny and rear-end are misaligned. But that's just a guess. I'd make sure that the tires are balanced also.

I don't think that the rear-end ratio has anything to do with it.

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Ted Stojkovski
Syracuse NY
Team Chevelle #172

 

[john6066]

i have a similar condition in my 69 454/4sp. what do you mean misaligned?? the rattle in my shifter is pretty much continual but gets worse with higher rpm. it's not speed because when i take it out of gear it stops. and if i rev the engine in nrtural it doesn't happen?????? any ideas john..

 

[Tintop55]

Tedster, Hi thanks for the reply! no I havent done any work to either the Rear end or the trans,,I havent owned the car that long ,and it has allways acted the same. I will take Your advice, and have the tires checked for balancing, along with an front end alighnment, and Im thinking mabey my U-joints might be gettin worn possibly....Thanks Again

 

[Wally]

I would start by having the driveshaft checked, the u-joints and check balance. If the problem continues it could be axle bearings, the pinion or side carrier bearings, junk tires or the trans. As you can see, there are lots of places to look.

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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette

 

[Gene Chas]

I just went through a similar problem. One thing with the driveshaft is that factory units are only good for 3000-3500 or so. ( So I was told by Denny at Denny's Driveshaft 716-875-6640 ). The other thing is that driveshaft vibrations usually don't go away like tire balance vibrations do. Usually.

Check all four tires for balance first. Then have a shop check your shaft. Mine was acutally out of round and had a dinged up yoke.

 

[Tintop55]

Walley,Gene, Thanks for the replys, I appreciatethe imput,,Ohh and Walley, Im not gona pretend that I was happy after reading what You said could all be wrong though $$$$$ haha but it isnt funny! I guess its kinda like leave no stone unturned then until I fiqure it out....Thanks Guys ....Tintop55

 

[L6571SS]

I get a vibration too, I found it is from exhaust resonace. I use to get it real bad at 100 or so when I changed engines it dropped to 75 or so but quits around 85 and starts up agian around 125. Most of the time I don't get moving that fast though. The driveshaft is the first place I'd look because it's is easy to do.

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JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports