Vibration 50 to 65 mph

Guru

RE: Vibration 50 to 65 mph

Lowfen · Addicted!

Have you checked the flex plate to ensure it is the correct one for the flex plate/ converter. Could it be cracked? I have had that problem on a street rod I did. Also is the drive shaft "phased" properly. I have a vibration in my Pontiac as well and have not yet sorted it out. But i am running an M22/3:73 gear set. Still when I get on it hard it really shakes up between 60 to 80MPH. So I will let you know how I make out over the next while. Good luck.

beaucarlo · Guru

Lowfen wrote:
Have you checked the flex plate to ensure it is the correct one for the flex plate/ converter. Could it be cracked? I have had that problem on a street rod I did. Also is the drive shaft "phased" properly. I have a vibration in my Pontiac as well and have not yet sorted it out. But i am running an M22/3:73 gear set. Still when I get on it hard it really shakes up between 60 to 80MPH. So I will let you know how I make out over the next while. Good luck.

hi...in regards to your laurention...i had the same prob with my 62 Impala....i found the cheap center hanger i bought from Carquest was missing some welds...it shifted over

under hard acceleration......i replaced it with the HD Timken hanger (I welded some addition gussets for insurance)..its available special order thru Carquest....smooth now

Pontiacanada · A Poncho Legend!

beaucarlo wrote:
Lowfen wrote:
Have you checked the flex plate to ensure it is the correct one for the flex plate/ converter. Could it be cracked? I have had that problem on a street rod I did. Also is the drive shaft "phased" properly. I have a vibration in my Pontiac as well and have not yet sorted it out. But i am running an M22/3:73 gear set. Still when I get on it hard it really shakes up between 60 to 80MPH. So I will let you know how I make out over the next while. Good luck.
hi...in regards to your laurention...i had the same prob with my 62 Impala....i found the cheap center hanger i bought from Carquest was missing some welds...it shifted over
under hard acceleration......i replaced it with the HD Timken hanger (I welded some addition gussets for insurance)..its available special order thru Carquest....smooth now

Ya, on older x-frame cars check the hanger bearing.

66 Beau · Poncho Master!

I think the '72 Lemans had a one-piece drive shaft. I'm 99% sure there is no steady bearing, or hanger bearing. One less potential culprit.

Pontiacanada · A Poncho Legend!

66 Beau wrote:
I think the '72 Lemans had a one-piece drive shaft. I'm 99% sure there is no steady bearing, or hanger bearing. One less potential culprit.

Right. '64 was the last year.

hawkeye5766 · Canadian Poncho Superstar!

A few things you mentioned
:I should also note the vibration is there even when you shift the car in neutral and let it coast.
This should eliminate motor,flexplate, tourque converter since your rpm should drop to idle rpm.
:I forgot to mention that I did switch tires over before. I borrowed a set from a buddy of mine who had a 69 Olds Cutlass.
Should eliminate tires/rims unless your buddy has a bad set too.
: So I am wondering now if maybe a wheel cylinder may be sticking, not allowing the shoes to fully retract.
If you have a dragging shoe walk around the car after driving/braking and see if one rim is hotter to the touch than the rest.
New axles,bearing etc. Thinking you may have an out of time drive shaft (can be ballanced but still twisted),bent spindle. Like others have stated,pull the shaft then pull the car. Good luck and hope you get it figured out.

Guru

rear brake flex hose ... they swell up from old age and hold the rear brakes on

musicman6120 · Member

Another update on my vibration issue. After extensive troubleshooting I think I may have narrowed down the problem. The bushings in my rear upper control arms have a lot of play in them and I suspect this is causing the vibration. Ordered new bushings so hopefully this will cure any vibration. Will update as soon as I can.

musicman6120 · Member

Finally got my vibration fixed. Turns out my spider gears in the rear were worn out, and were causing the vibration. Got the rear end totally rebuilt and with bigger gears. Car rides smooth now.

4SPEED427 · A Poncho Legend!

Wow, that IS an odd one.... Who would have guessed. How did you figure it out?

427carl · A Poncho Legend!

I wondered that thats what I was going to suggest next biggrin biggrin biggrin

GLHS60 · Poncho Master!

Mrs Hicks: Wake up, wake up!!

Carl: Awww Mom, I was having a dream about spider gears causing my car vibration..

Mrs Hicks: Never mind that, get dressed and off you go to school !!

Carl: O.K. Mom, sure was a weird dream... yawn

Thanks
Randy

musicman6120 · Member

I ended up bringing the car into a reputable drivetrain shop, since I had exhausted all my options. They took my diff cover off and checked my spider gears and they were worn out. They figure they were chattering and that's what was causing the bad vibration. I ended getting the open differential which had 2.50 gears, replaced with 3.42 gears and a posi rear end. The 2.50 gears aren't the original gears so one of the previous owners obviously replaced it with a donor. According to the build sheet the car came with an open diff and 3.31 gears. Engine revs a little higher but I have a lot more power at my rear wheels now.

oshawacliff · Poncho Master!

Great news.
I had been following this thread

Another lesson learned.

Cliff