Vibrations

1970GrabberCoupe

Member

Nov 23, 2016

7

2

13

Southern Maine

Nov 23, 2016

#1

• Nov 23, 2016

• #1

Hi,

New to this forum. Wondering if anyone would have any suggestions on a vibration that is felt from 2300rpm+ which is making my car pretty unbearable to drive at any speed above 45.. I've replaced the ujoints front and rear on the driveshaft this past summer. Tires are "fairly" new but it doesn't hop like a abnormal tire..

Car :
1970, C4 trans, and 8in axle. The tire/rim size is different too, r14rims with 55 series front, r15 with 60 series rear.. Pinion angle?
It also slams extremely hard into reverse which I am wondering if it could be connected to the vibrations.

Thanks!
Kyle.

 

The Shemdogg

Active Member

Mar 15, 2016

137

23

38

san jose CA

Nov 23, 2016

#2

• Nov 23, 2016

• #2

Did the vibes show up after u did the ujoints? Driveshaft may not be centered causing the wobble. If your tires have hi/lo spots thatll cause vibes n road noise. Maybe your wheels need balancing or the suspensions worn eating the tires.

shem

 

1970GrabberCoupe

Member

Nov 23, 2016

7

2

13

Southern Maine

Nov 23, 2016

#3

• Nov 23, 2016

• #3

It had a minor vibration before I did the ujoint but it's gotten worse. I'll check those areas you addressed. Thanks! Been reading up on here and other areas, some say "clock" the driveshaft, mark it and find the natural balance? I marked it when I removed it before but maybe the people before me did not. Hmm.

Thanks,

Kyle

 

The Shemdogg

Active Member

Mar 15, 2016

137

23

38

san jose CA

Nov 27, 2016

#4

• Nov 27, 2016

• #4

if you rev the motor above 2300 in neutral do the vibes go away? Maybe get a new driveshaft. If yr driving and you put in in neutral at speed do the vibes go away?

shem

 

1970GrabberCoupe

Member

Nov 23, 2016

7

2

13

Southern Maine

Nov 28, 2016

#5

• Nov 28, 2016

• #5

It doesn't shake too bad in neutral above 2300, there is a minute vibration but on another note it may be time for new motor mounts, been watching the engine when I shift it, she jumps down hard right.
I do think your on with that driveshaft maybe being the culprit, this winter I might pull it and have it checked over, balance and damage.

Kyle

 

tos

Founding Member

Apr 27, 2001

896

68

59

Cincinnati Ohio

Nov 28, 2016

#6

• Nov 28, 2016

• #6

I would take care of the motor mount issue first. I would also check the tranny mount and make sure its good. Either one of these can cause vibration.

 

The Shemdogg

Active Member

Mar 15, 2016

137

23

38

san jose CA

Nov 29, 2016

#7

• Nov 29, 2016

• #7

The motor moving down is normal when going into gear. If It goes down n shakes too then u got a bad motor mount. That wouldnt make the car feel like its shaking itself apart. Leave it in 1st and see if u get the same wobble around 2300rpms. Or just throw another driveshaft at it, should be able to find one cheap

shem