Hey guys, hope you can help this girl out. I've had my 1995 F-250 7.3 L Powerstroke, 2WD in a couple of repair shops here in Oklahoma, one being the Ford dealership to try to fix the following problem:

When driving around 45-50 MPH, the front end of my truck will start shaking violently. It seems to be located more on the driver's side and is mostly brought on by hitting a bump. Now it does not do this all the time, or every time. It is selective about when it happens almost as if it has a mind of its own. When it starts to shake, you can slow down until it quits and then go on. At times around the same speed, you can almost feel the shaking begin to happen, but then quit.

I've had repair men tell me that is everything from the flywheel to the tires, to the tie rod ends, pittman arm, etc.

I had the flywheel checked, all bolts are tight and everything is fine. I have had it in three different front end shops, each telling me something different. One says everything is fine, the other says replace everything, the other says install a steering stabilizer.

I know the basics, but not enough to make the decsion, and I am afraid that someone is trying to make a quick buck.

Someone please help!!!!! Any advice would be appreciated!

 

Hard to diagnose without putting hands on vehicle, but try this:
Move front tires to rear, does the problem change?
How are the shocks on front axle, when were they last changed?
This is a 2WD vehicle, raise each front tire and try to move it top to bottom (opposite of turning), to see if there is play in the suspension. You should also repeat this test with the tires on the ground.

You can check the tie-rods, drag link, etc. by crawling under truck with it on the ground. Have someone turn the steering wheel, you should see all linkages move in the same manner without delay.

Good luck, let us know what you find.

 

Already changed the tires, this was NOT the problem. Already checked all the play in the tires, none what so ever. What now???? I had a friend mention U-Joints, or the possibility of it dropping an injector? Any chance these could be it? Oh yeah, thanks for the quick reply!!!

 

I don't see how the driveline or powertrain could cause the symptoms that you are describing - but I am no authority.

You didn't mention the number of miles on the truck, the condition of the shocks, or if you feel the vibration telegraphing through the steering wheel.

 

The truck has 110,000 miles on it, 26,000 on its brand new powerstroke engine (installed during warranty by Ford due to defect).

The shocks were replaced approximately a year ago around the same time as the engine,...... so around 26,000 miles ago.

Yes, when the truck decides to shake, you can feel it through the steering wheel as well as every bone in your body!!

 

Ah, the plot thickens...

Is it possible that the shake started after the engine was replaced and has been getting worse over time?

This is my last ditch effort so here goes:
1). Motor mounts
2). steering linkage
3). Frame members under the engine, including the transmission tailshaft mount and support.

I'd climb underneath and try to move everything and check all bolts/nuts. It is not a small task, but I have seen the smallest detail manifest itself in a major fashion.

Good luck, wish I could be of more assistance.

 

Thanks for all the help you have given so far. Trust me it does not go unappreciated. When so many different people were telling me so many different things..... yes it's good, no it's bad, replace everything... I didn't know where to turn.

As far as the shaking, no, it did no do it after the motor replacement.

I will try what you have suggested. Will post a report later this evening or early tomorrow morning.

Thanks once again!!!

 

I may be wrong but, I'd vote for the shocks. You say it starts after you hit a bump. Bad shocks will do that. Years ago I had a 78 350 that shook like that, especially after a bump. Does it feel funny in curves? It's possible to get bad shocks or even under-rated shocks. Good luck.

 

Continuing with the shock theme, I forgot to ask.
Are the front shocks dry?
If not you may have had a failure and the shock would loose all its fluid.

 

Not sure if the 2wd were a solid axle design back then or not, but if so it could be the Trackbar bushings and front shocks. We have a fleet of F-superdutys and are always replacing the trackbars and front shocks on our trucks. All of are trucks have the solid front axle. Good luck with it.

 

2wd, violent shake after bump.........Being an offroad guy I say upper control arm bushings and bolts. Check the bolt holes for wallowing out. I have seen this problem at least 20 different times and it was always because..."I turned up the tortion bars a little to fit bigger tires." But those were all 4x4's with IFS. I don't know the configuration of the 2wd front, but if it has upper control arms, I bet you a dollar that's where your problem is. Look at the bushings and bolts very carfully. You should be able to see where the head of the bolt has moved around, or where an A arm has contacted the mount. That's just my 2 cents.

RubberDuck

 

I have had this exact same problem with 2 of my pickups. The first, a 76 Ford shortbox/regular cab. It would start shaking in an off-kilter bump (railroad tracks not exactly perpenduicular to roadway) at any speed over 35-40MPH. Then slow to about 20 until the shaking stops then accelerate to cruise speed. This crap was scary......the entire front of the vehicle would hop left and right and the steering wheel would almost rip your hands off. Turns out it was a combination of a bent wheel and an improperly balanced tire on the right front. Mounting the bent wheel/tire on the rear axle solved that.


Second pickup (my present 1 ton cc longbox) exibits those traits when I get to adjusting the rear anti-wrapup bars on the axle and get them too tight (preload). It's like the frame is flexed in an unnatural way and the steering geometry doesn't like it.


I have a feeling that you're dealing with an out-of-whack caster issue. I've never been a fan of Ford's TTB or Twin I Beam (such as your setup has) because ALL three major alignment measurements/angles (Caster, Camber, and Toe) change as the suspension cycles. When the coil springs in your front-end begin to sag (VERY common in any Twin I Beam with more than about 6 or 7 miles), then camber goes negative, caster goes WAY positive, and toe will ususally go out a little (tie rod 'flattens out'). A little positive caster is what you want....it helps keep the tires pointing in a straight forward (self-centering) position. Too much caster and directional instablility takes over....ever watch shopping cart wheels when you go really fast? They start to shake. Same as too much nagative caster. Maybe when you hit a bump and the conditions are JUST RIGHT......you get the idea.

Just an idea......]

Cody

By the way, the two pickups that have done this:
1. Totally unrelated reasons for shaking
2. Lifted to the moon (76 has 39" tires, 95 has 44" tires) so alignment as far as caster and camber are off.

 

I had this problem with an 88' GMC Siera 4x4 and it turned out being the steering box was coming loose from the frame, that made the truck jump back and forth severly. I also had this problem with a 00' F-250 PSD 4x4 and that one was a bad bearings on driver side, so Ford replaced the bearing on both sides and the axle, but that one was more like a severe vibration. As a matter of fact, it vibrated so bad that when the mechanic took it for a test drive that he got scarred and had to pull over to see if the wheel was falling off.

 

My truck did the same thing as yours but there are many different variables. First here is what my truck is 1999 F250 Super Duty 4x4 x-cab 7.3 auto tranny.

At 140,000-150,000 miles every now and then my truck would start shaking very very badly when at the same speeds you indicated. Some times it would do it at slower and faster speeds but seemed worse around 50mph. On some accasions I'd get out of the truck and walk around the truck expecting to see a totally flat tire. The problem would occure sometimes twice a day (drive a minumal of 120 miles per day) to once every couple weeks.

At 150,000 miles I installed new rotors, callipers, pads, four greasable ball joints (Precision), outer and inner hub seals, axle seals, u-joints, and Warn Premium lock outs. The truck now has 154,000 miles and it's never shaken once.

I really think it was the lower driver side ball joint that was causing all the problems as it was really shot and was perhaps 30,000 miles beyond due.

Hope some of this may help. BTW, it really shook bad, a passenger that witnessed the shake was really freaked out. Said I should stop driving it ASAP and fix.

Now my passenger rear leaf spring is broke, more fixin more $$$!!!