Truck shaking

I have a 1981 ElCamino truck that vibrates at 60mph and above, I have put new tires on it had them balanced twice, had the drive shaft balanced, axles have been checked and the front end has been worked on also, but the vibrations just will not go away. Does anybody have any ideas as to what this can be caused from? I have run out of ideas and so has my mechanic.

This can come from out of round or out of balance rear brake drums. These often get overlooked but sometimes create this kind of thing and keep it elusive. I’m assuming the wheel bearings have all been checked and double-checked.

I can tell you about a vibration problem that I had in an older truck. It wasn’t cured till I replaced one of the universals. The mechanic tried everything and told me the universal had acceptable play. I told him to replace it as it had much more then when it was newer. He did, the vibration was gone !!!

Balance of course first comes to mind, alignment second, Has it been in an accident third, sometimes, engine misfires can cause a situation as described. How do the plugs look?

Make sure there is zero play in all the U joints. If any movement at all is felt when hand twisting across a U-joint, replace it. Using a dial gauge, have the run out measured on the tires, both for out of roundness and axial wobbling. Double check all the steering and suspension components, bushings, ball joints etc, and replace any that are suspicious. Any sign of cracking rubber in a suspension or steering bushing for example, that bushing should be replaced. On a truck of this vintage, that may mean all of them. This does have the symptoms of a drive shaft balance or wobble problem. Consult the Popular Mechanics Complete Car Care Manual, it has a section on common techniques to balance a drive shaft. Sometimes you have to experiment a little where the weights are placed to get it right.

Have you had the wheels checked?

Try swapping the tires around. That ought to change things. If it doesn’t, then you can pretty much eliminate tires and wheels.

My Dak had the same problem the other day,it would take an intermittent shaking fit(I had aired the tires a little over stock pressure) but hasnt done it since ,I wonder if the 4wd was completly disengaging-Kevin

Is the vibration coming through the steering wheel or the seat? If any of it is coming through the seat, your engine could be the source. A broken mount, uneven compression, and other possibilities that might be found on an analyzer exist.

If I remember correctly, didn’t ElCamino with the auto trans. start using a lock up torque converter in '81 or '82? if this is the case you might try unplugging it, see if that helps. Just as a aside since when was that Malibu mutant ever considered a truck?

I liked the concept. I think there’d be a market niche for it even today. Even the small trucks have grown too big for my taste. A nice car/truck hybrid would be welcomed.

I’ve always liked the ElCamino, but I don’t think it was ever considered a truck even by GMC or Chevy.

Guys, check out this old propaganda

You can skip directly to page 44

Notice the logo on the bottom right

If you actually read some of the stuff, GM seems to imply the El Camino was a truck

Perhaps, but I think everyone who bought one knew what they were buying, a car with the ability to occasionally carry things like plywood and a snowblower that won’t fit in a car. I’ve no doubt that an occasional owner loaded the bed with concrete blocks until the axle hit the stops, but those people would have loaded their cars up with concrete blocks too.

@db4690,

Thanks, in that it is refer ed to as a “light truck” several times, even though is has been built on a car chassis since the beginning. Biscayne, Bel Air, GM A Body (Chevelle, Cutlass, Skylark etc.) and G Body.

Even though an El Camino may technically be a truck, I’d never dream of using it like a work vehicle, such as a Sierra, F-150, etc.

Just for the record, I’ve never owned an El Camino

I think an S10 or Ranger would be more useful than an El Camino, for your occasional weekend projects

I appreciate all of your comments and will have them looked into. I just used the word “truck” for the sake of calling it just an ElCamino. I have had it since 1985 and I would not get rid of it for anything. It has a new engine, transmission, u joints, steering components and a whole lot of other stuff has been done to it, including new paint job, and interior redone.
Thanks for all of your comments.

@dlucas5‌

For the record, I have no problem with you calling your El Camino a truck

Sounds like a pretty nice ride, by the way

I have the ElCamino in storage, only take it out about once every two to three weeks, it has never been used as a truck. I have hauled some small stuff in it from Lowes to the house, but that has been about it. I like being able to use it as a “car” also. It gets a lot of compliments when I do have it out.

Dont see why an El Camino wouldnt be about as good as a standard half ton pickup ,thought they were constructed on a station wagon chasiss,I remember the wheel bearing problems we used to have with our old Ford pickups(non floating rearend) you lose the axle seal,the bearing would die soon after)-Kevin