Hey guys, got my static '94 extracab.



At 45 and 70, have a vibration that I can't track down.

It feels like a tire balance issue, but it isn't. I think... I've noticed that the bed oscillates slightly when I feel it. The frame is notched and the bed is cut out just where the notch is but I'm not convinced that the bed or the frame are the issue.

I've replaced a lot of parts trying to chase this down:
4 tires
rotors
drums
had the tires road force balanced twice.
Had the rears trim balanced on the truck.
alignment - where we found one bad ball joint.
Idler arm
center drag link
shocks
three U joints,
carrier bearing for driveshaft


I've checked the engine mounts, tranny mount, wheel bearings, steering linkage ball joints, and all the body and bed mounts. I've checked my welds on the frame notch (they look fabulous!), and had the third member apart.....

Are there any more parts on the truck?
Considering just giving the truck away to some hispanics that live down the road to use as a work truck.....

 

Ok, good questions, here goes...

Joeynational - Checked my balls, they SEEM fine.... no play in any direction.
Also, check your alignment, had the pull, then alignment, then gone... Castor was off on one side.

Dailydragger - It's not likely, the street here are all pretty good. For two years, I only drove it one or two days a week.

Nam - Can't find any slop anywhere. I've jacked the thing up once or twice a week for the last couple months, trying different things...
Doesn't feel like a driveline vibration, the carrier bearing only installs one way and mounts correctly. When I had the rear tires Trim Balanced, they jack up the axle with the weight of the truck on it and run it to 55mph holding the other tire, so the wheel they are balancing is actually spinning at 110 mph.

Cmcpher - Yeah, it stop between those speeds.

ShoNuff - Can't be loose lugnuts, I torque and re-torque every time I pull the wheels. I watched the fellow balance them not too long ago, he did 'em right. Also they've been balance multiple times with different tires, hasn't changed a thing.

Sound.Vision.Soul - it's been around for a while, don't remember when it started. Since I was only driving it a day a week, it was high on the priority list to track it down. Now it's been so long, I don't remember what work I had done right before it started.

 

Is it possible that either the hole in the bed or the notched frame could allow a resonant vibration to occur?

The reason I ask, is that when I drive down the road while the truck is shuddering, I can see the bed oscillating. If I bang on the bed above the taillight in a downward direction with the bottom of a closed fist, I get the same vibration and it quickly fades away. I can't see any visible twist in anything. I've checked all of the bed bolts.



You can see my cross members, the only one that I removed was the gas tank crossmember. I didn't replace it with a full length one.

I just had an idea..... be back...

 

I just happened to notice the 40mph vibe while going 5 over in a 35. And yes, I jump on I-95 to get to work every day where the limit is 70.
The vibe is constant at speed regardless of RPM.

ShoNuff didn't mean that... I will check the lugnuts and wheel. I know i've got tapered lugs.

The driveline is tight, just went through that with a fine tooth comb, but have had drivline vibes on my 4x4 and this vibe is nothing like that.

I added a temporary crossmember this morning and found that it made the vibe different, I can def. see the bed shaking now, tightened the bed mount bolts again too.

If I add weight (a buddy) to the back of the bed, the vibe is almost gone...

Thanks for all your input guys, I really appreciate it.

 

They are OK. I got an itch last night to install some degree shims that I had and angle the front of the diff down a bit. It changed it a bit, but worse. Now I can feel a different shake when I brake.... driveline for sure.

 

Well, the shims did change the pinion angle, but introduced more vibrations. I'm thinking that it may be the output shaft bushing on my A43D transmission. Anyone know anything of these?

Finally breaking down and taking it to a friend's shop who works on Toyotas. So frustrated...... let you know.

 

Yeah right?

I think I have located it. I believe that it is the center u joint angle on the two piece driveshaft. Having gone through literally the whole of the truck with a fine tooth comb, I changed the gears in the rear end and the vibration changed speeds with it. The speedo is off 15 mph at 70, but the vibration still shows at an indicated 35 and 70, so the problem had to be either the tranny or the driveshaft. I replaced the output shaft bushing and it's still there, so I have located a dual cardan (from my old 4runner) and am going to have it lengthened to replace the back half of my two piece driveshaft. It will split the angle between two joints instead of one.

I will update when I get to it...