Vibration

[meadowbrook]

Hi folks.

Can I get some opinions on the causes of a high speed vibration between 60 and 70 MPH on my 1950 Dodge Meadowbrook?

Now that I have an overdrive from Mr Asche, I am able to drive at faster speeds since the engine does not labor as much and with these new found long legs, i notices a high frequency vibration felt through the seat that peaks at ~65 and by 70 and beyond, goes away.

I suspect the drive shaft, which has the original ball and trunnions. The car has 75K original miles and besides the new trans is stock.

I hope it's not the 'new' trans .

[Alshere59]

Just a quick question. Did you fill the overdrive and the transmission with lube? Two fill points. Also what did you use? I think it is probably elsewhere but never hurts to look at the most recent change.

[Jim Yergin]

Have you had the wheels balanced lately?

Jim Yergin

[meadowbrook]

Yes on both counts, I filled the OD with Diesel engine oil from Amsoil provided by George Asche when I bought the trans from him and the wheels and tires are branks new and balanced.

[greg g]

suspect a worn u joint. However you might try unbolting the trans end of the drive shaft and rotating it 180 degrees and reattaching it. A lot of times that will work. to counter vibrations.

Usually out of balance tires will have two imbalance harmonics 30/40, and again at 60 or so.

[michael.warshaw]

could be your tires have flat spots

[ptwothree]

I just had the e-brake drum off mine to install a new rear seal in the trans. It was amazing the amount of dirt, grease and other junk that had accumulated. Maybe enough to cause an out of balance condition.

Just my 2 scence

[Dodgeb4ya]

On the R10 overdrives when running in OD mode, if the rear case to ring gear clearance is excessive you will feel a kinda rumbling vibration depending on how worn the rear OD case is. The car won't rumble when in 3rd direct-only OD.I show a picture of how this ring gear to case clearance is checked in my B4ya pics.

Flipping the driveshaft end to end and seeing if that changes your vibration issue is another way to check the drive shaft.

Bob

[meadowbrook]

Thanks so much for all the responses.

I will have the shaft balanced and see what happens.

[greg g]

If the cross and roller U joint is beginning to wear, balancing won't do much good.

Do the 180 flip first (ten minutes work or less) and see if it makes any difference before spending the bucks for a balance.

The tendency for these types of joints is to run in one place, and they will wear more in the spot where they run. that bit of slop will lead to vibration, If the 180 rotation doesn;t work, swapping it end for end will make the joints work in different (more to spec) spots, might also do the trick.

Unless you rebuild both joints, the balacing will probably be a futile exercise.

[P-12 Tommy]

suspect a worn u joint. However you might try unbolting the trans end of the drive shaft and rotating it 180 degrees and reattaching it. A lot of times that will work. to counter vibrations.

Usually out of balance tires will have two imbalance harmonics 30/40, and again at 60 or so.

I agree

Tom