1984 Dodge Van Van shaking at 45mph

BROWNSUGAR1984

MEMBER
1984 DODGE VAN
V8
2WD
AUTOMATIC
166,000 MILES

1984 Dodge Ram Van B250. 166K mileage. A couple of weeks ago, my van started shaking at 45mph. It does fine up until 40mph, but then it starts to shake and rattle pretty heavily at 45mph. The shaking gets less severe over 55mph. The interesting thing is that it only happens when my foot is on the gas. If I am going 45 or 50, the car will be shaking as long as my foot is on the gas. If I take my foot off the gas pedal and coast, the shaking stops instantly, no matter my speed. I was due for new tires so I just got some brand new tires (along with balancing) and this didn't fix the problem at all. I got them done at Wal-Mart though so I'm not 100% that they were balanced very well. Any help would be greatly appreciated. Thanks!

5 Replies

MIKE H R

MECHANIC
3,094 POSTS

Check the driveshaft, and drive line. First thing to check is the universals to see if one is bad. You can tell this by getting under it when it on a lift and with it in neutral turn the drivshaft back and forth, most times you can feel if the universal is bad. If the universals are ok check the rest of the drive line

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Saturday, May 9th, 2009 AT 7:21 PM

BROWNSUGAR1984

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Thanks for your feedback. If I do not have access to a lift can I put the car in neutral with the emergency brake on and crawl under the van to do this? If I understand what you are saying, I should grab the driveshaft and try to rotate it. How will I be able to tell if it is bad? Will it feel a little loose?

Also- being somewhat new to this, if the u-joints seem ok, what are the other components in the drive line that could cause this?

Finally, do you have a rough idea of what a repair for this problem might cost? Thanks so much.

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Saturday, May 9th, 2009 AT 7:47 PM

MIKE H R

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3,094 POSTS

If you can't get to a lift make sure the tires are chucked making it so the van wont move. Put the van in neutral and brake on. When you get under it then grab the drivshaft and try turning it each way. With the wheels on the ground the van will have to be in neutral. You will feel if they are bad, there will be free play when turning it one way then the other. The rest I was refering to was the rest of the driveline. To see if anything looks like it has shifted. This is not saying there could be something else wrong but the universals are first thing that comes to mind. If they are not the problem try having someone walk alongside of van while you are driving slowely, have them listen for any noises to pinpoint where the proble could be. If you can't find it I would take it to a garage and just ask for them to check it on a lift.

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Saturday, May 9th, 2009 AT 8:18 PM

BROWNSUGAR1984

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3 POSTS

Thanks again for your input. So I checked under the van as suggested and sure enough the u-joints seemed shot. I took it in and had them replaced, and asked the shop to see if anything else under there could be causing the shaking. They confirmed that the u-joints were shot and replaced them, however this didn't fix the shaking. They said the tire balancing was fine. They noted that the rear trans seal has a leak and that the shaft coming out of the trans that connects to the drive shaft has "lots of play." They recommended taking it to a trans shop and having a "sleeve" put over it that will take care of the leak, and limit the amount of play. They said they are "95% sure" that will fix the vibrations.

Does this sound plausible? From internet research it sounds like those sleeves are more for taking care of small leaks, but would they also reduce play in the tans shaft? Do you think it would possibly fix the shaking problem?

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Monday, May 25th, 2009 AT 5:26 PM

MIKE H R

MECHANIC
3,094 POSTS

If you can get a book that shows the transmission breakdown, On the transmission side there is a shaft that the yoke slips over. The yoke is the part of the driveshaft where the universals are. The sleeve works to stop end play wabble. Then after that the seal is put on. Without the sleeve there would be a more of play in the shaft comming out of the end where the yoke goes on and could make the seal leak. Next with the seal leak check the fluid in the transmission make sure it is at proper level. You don't need to tun out of transmission fluid.