When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've developed a pretty good vibration in the '87 from about 45-50 mph on up. It feels like a lean condition in the engine, but there's not many vibrations being transmitted though the gear shift. Here's what I suspect...
1. I know I have a loose lower ball joint on the driver's side. It may have worn enough to put up a vibration, but it doesn't seem to be in the steering.
2. Lean condition caused by failed O2 sensor. I need to check codes first...
3. Wheel(s) out of balance. Again, the vibration feels more general than specific to front/back or side/side but its possible.
4. Failed harmonic balancer - a real possibility since I haven't had any luck getting the timing marks to line up with the indicator to set the timing. I've never experienced what a failed balancer feels like to compare to.
5. EGR issue - disconnecting the EGR vacuum line and plugging the line improved performance from a dead stop, but still vibrated once at cruising speed.
I'm open to suggestions as I really want to get this back on the road without destroying anything else along the way.
Ah all that you named and maybe a drive shaft u joint? Have you lubed the slip spline lately?
Swap tire positions (front to rear) and see if it moves....
Motor mount, trans mount, worse case (hope not) pinion bearing.
No slip spline on it. It mounts to the transmission similar to an automatic. The U-joints are new and recently lubed. The vibration was showing up prior to tearing it down so the rear isn't responsible.
I crawled under there and inspected the balancer. There are some tears in the rubber and a small amount of side to side play, but I wasn't able to find any rotational slip, but I didn't have the drivetrain locked down very well either.
I'll put a tire rotation on the list and see if that does any good.
I'm going to take back the power steering pump core and pulley tool. I'll grab a ball joint tool and the upper joint (already have lower) and change that out as well.
In the meantime, I'm reserving driving it for testing purposes until I figure it out. I don't want it to tear itself up for nothing.
Time for a dope slap and someone to shout "Well d'uh!"
I believe I found my vibration - I got the truck in position to work on the front ball joint and did a quick survey of my wheels. It appears that I have a rear tire without a single balance weight on it. I'm so embarrassed. I haven't driven a truck in so long that I forgot what it felt like to have a wheel out of balance...
I also suspect that I had a stuck u-joint as well. It still vibrated a bit after the wheel balance, but seemed to free up and run smooth as silk. After minimal use for the last year, I suspect even a new u-joint will get sticky. If it recurs, I'll pull the driveshaft and check them...