95 Explorer Sport 4x4 - Strong Vibration on Coast

[Dan-in-DC]

Help! Just had trans completely rebuilt. Got it back from the shop about 2 weeks ago. Was running pretty smooth at first, except there was *occasional* intermittent slight vibration at city driving speeds (25 to 50 mph). At first I thought slight vibration was probably caused by uneven pavement, as several roadways near where I live had been recently resurfaced.

However, now, less than 300 miles since the trans rebuild, in last few days have started getting even more vibration -- but only on coast. This became substantially worse this morning. Smoothed right out on acceleration, but then the whole truck began to shake as soon as I let off the gas.

When I had bought the Explorer, the seller had told me there was a trans problem, so we had it towed directly to the shop for the trans rebuild.

Previously, I had only driven it across the parking lot at the seller's condo. So two weeks ago was the first time I had ever actually driven this (or any) Explorer on the road, and consequently I don't have any baseline for comparison.

Same vibration happening whether in 2WD or 4WD automatic mode, at speeds as low as 30 mph. Tire pressures are OK, tread good, all wheel lugs are tight. Not making clunking noises such as might be characteristic of bad u-joint. Shook so much today after driving neighbor to work (but only in coast), that I was afraid to drive it home faster than maybe 20-25 mph.

(Not sure if this is significant or not, but sometimes - not every time - it does make a slight clunk when going into automatic 4WD mode. My house sits on a hill and has a fairly steep uphill dirt driveway, and I usually shift into 4WD as I'm approaching the driveway.)

We sort of bought this Explorer for my wife, as my Bronco with its 31" tires is just too big for her to drive. She loves the Explorer, and so do I, and we plan to keep it for a long long time. But now our Explorer needs expert help!

Anybody familiar with this sort of drivetrain vibration problem? Any suggestions where I should begin looking?

Thanks,
Dan

[emac2001]

i just went through a vibration issue with my 95 sport. ended up being the bolts for the rear driveshaft loosened up and vibrated off. had 1 bolt at 2 threads left when i finally found it. since the trans was just done, check all the bolts around it. maybe they just didnt tighten the bolts enough. also, to check the front end, put up on jack stands and remove tires. i had bad ball joints and was unable to tell by grabbing the tire as most people do. it showed clear as day when i grabbed onto the studs and lifted up and down. hope this helps.

[Dan-in-DC]

Originally Posted by emac2001

i just went through a vibration issue with my 95 sport. ended up being the bolts for the rear driveshaft loosened up and vibrated off. had 1 bolt at 2 threads left when i finally found it. since the trans was just done, check all the bolts around it. maybe they just didnt tighten the bolts enough. also, to check the front end, put up on jack stands and remove tires. i had bad ball joints and was unable to tell by grabbing the tire as most people do. it showed clear as day when i grabbed onto the studs and lifted up and down. hope this helps.

Thanks. I'll check that out. "2 threads left" sounds awfully damned scary. Taking the Explorer to the shop that did the trans on Monday or Tuesday for checkout. unfortunately there's no place to do it at my house. Problem did come up rather suddenly, maybe something did work loose. If I find out what's wrong, I'll post it here.
Dan

[emac2001]

any word on the vibration?

[JDraper]

I had a similar problem with my '94. It turned out that the nut holding the rear output flange onto the transfer case had worked itself loose.