I am still having a vibration on my 1994 4x4 explorer. I have replaced the tires, radius arm bushings, shocks, and have had it aligned. They can not find anyting wrong with the front end. The vibration starts about 60 mph and is felt the worst in the floor. It will smooth out around 75, it also comes and goes it is not constant. I was wondering if the u-joints could be getting dry. Another question what is the rubber boot on the drive shaft will that cause problems. Any help would be greatly appreciated, I just keep putting parts on it and nothing seems to help.

 

forgot to say it has 120,000 miles on it.

 

Have you checked the trans mount?

 

Wow - do we want to start another 15 page thread on Explorer vibrations?

Let me first answer your questons, then we can talk theory. I still have the 60-75 MPH vibration too.

Driveshaft U-joints can contribute to vibration, sure. Mine's a 93 and I changed the rear drive shaft u-joints at about 150K - no change. The old ones looked fine by the way.

Rubber sleave on driveshaft - front and rear and also on the right hand front drive axele if you look at it. These are all splined slip joints. The manual says to grease these every once in a while. I never have. Never leaked or ripped a boot so no need to look at it...OK I probably should some day. I would think if this has dried out and gone bad, you'll hear it before feeling it on the road.

Tires - that's a good one. You may want to go back and have them rebalance them. Funny thing about tires....I just replaced all 4 ball joints, all the rest of the bushings have now been converted to poly-urethane. Found out my front shocks were loose a while back - that eliminated 1/2 the vibration. So now with all this done, I finally get it aligned again. The camber was off on one side so it pulled right and even a little tug right when hitting the brakes. Alignement numbers looked perfectly sysmetrical yet it still pulled right. Rotated the 2 front tires and now goes pretty much straight. I immediately hit the freeway to see if the vibration was now gone - no! It was just as bad as it ever had been. Now 2 weeks later and a few hundred miles, the vibration is barely noticable. I guess the tires had to break in differently after the rotation?

So for me, I'm think the 6 year old, 50K+ miled BFG AT's are in need of retirement. But there's a good 15-20K of tread still left....

Transmision mount - this was just replaced about a month ago with the rebuilt tranny. The old one was ripped and could have also contributed to thevibration. But waht about motor mounts? I can't even se them to inspect them...could also be another source.

So go back and check everything tht holds the tires in place. Tie rods, ball joints, wheel bearings, shocks....If all is tight, should not have the vibraton as long as the tires are balanced.

 

I had not even thought about the transmission mount. I guess that would cause some vibrations. From what I am reading this vibration is a common problem on these rigs. I do not think it is a U-joint problem. I might just have to live with it I dont want to drop to much more money in a 12 year old vehicle if the problem will still be there. I just didnt know if it was going to hurt something.

 

Vibration like this is not good. You can shake all kinds of things loose and eventually stuff breaks from metal fatigue. But one key point is that it didn't used to vibrate - why is it now? Ford added two heavy metal dampers - one off the rear diff, front right and one off the t-case, rear left. 1993 first had these and your 1994 does too. So there were obvious design issues but you have all the Ford fixes. So that's why it goes back to - what changed as it didn't used to vibrate? I am now convinced it's my tires...but have changed out everything else at this point except the tires. And I can affect the vibration by rotting the tires around so it's kind of obvious now. Try rotating yours - could have a bad, new tire. You probably have something real obvious but just not found it yet.

 

would the tires cause the vibration to go away for a few minutes and then come back.

 

Maybe - It was really an eye opener for me to drive the truck and get shook like the devil after swapping the front tires and a week later, with no changes the vibration is now barely noticable.

 

thanks for the help I will start by rotating and balancing the tires.

 

Well my vibration is finally gone after ~5 years of it. Added suspension lift and 31" BFG AT's back in May 2000. New alignment and it ran great - straight and smooth. Was about a year later I first noticed a ~65 MPH vibration.

Finally got around to have the tires rebalanced and it didn't help. Spent the next 4-5 years changing out all the bushings, shocks, new rear leafs (went up to 4" lift), 4 new ball joints, new front bearings, alignment....still vibrated.

Would not go straight after alignemnt. Rotate tires and pulled the other way...starting to suspect tires - looks like that was back in Feb this year.

2 weeks ago coming back from a road trip in the heat of the mid day and the vibration got, oh just a little worse. I thought all 4 tires were falling off the car. Pulled over - all lugs tight, no flat tires...but I saw huge buldges in the tread of 2 of the tires. The belts had started to seperate. Swap the worse one with the 235 sized spare and limped it the rst of the way home, 60 miles at 60 MPH.

Put on a set of goodyear wranglers, same 31" size. Now it drives straight (alignment still good) and no more vibration! Feels like it did back in 1993.

All my old wheeling budies used BFG's on their jeeps. No one ever complained about a problem like this. I stayed away from BFG's this time since it seems they only lasted about a year before I started getting vibration...but I did stretch 59,000 miles out of them.