2 seconds of heavy vibration??

[flewism]

Our "99 Explorer, V8, AWD, is getting a severe vibration for a second or two on acceleration. This doesn't happen from the takeoff but somewhere between 25 and 40mph it will vibrate then smooth out. It will not vibrate constantly at any speed. It is from the front and appears to be a drive line issue.
This vehicle is not driven everyday currently but it will be this coming summer when my son start driving. We have owned it since new, 162,000 miles.
We basically, parked it last summer when my daughter bought a new car. I drove it some this winter without incident . My daughter's car went in for collision work earlier this month. So she drove this Explorer to school and work daily while her car was in the shop, and that's when it started.
I'm going to put it up in the air tomorrow, to see what I can see.

 

[unclemeat]

Have you checked the drive shafts?

 

[dynamite196]

are the wheel's balanced? winter pot holes do a number on the wheels

 

[flewism]

The main drive shafts universals are tight as they were replaced a couple of years ago.

I don't see it as a tire out of balance. This truck ride very well 99.9% of the time. It take off smooth as silk and shifts nicely (auto). Then I will get a second or two of hard vibration and she continues to run perfectly after that. I does not seem to happen at the same shift point or any shift point, it seems completely random within a range. I have yet to be able to prolong this vibration by maintaining a constant speed at any level. I have manual shifted the transmission from one to drive and it still does it but not necessarily when I shift. Switching in and out of overdrive does not change anything. It does not seem to matter if it is a very hard acceleration or feathering it up to speed. In between 25mph and 40 mph so far is the only reasonable constant I have.
The transmission is original and has been serviced at least twice, the fluid color is good. Ball joints and tie rod end have been replaced once at about 100K and still seem good and tight. Hitting bumps in the road does not seem to set it off.

 

[dynamite196]

If everything else in the drive line is good, I'm betting on an out or round tire or a bent rim.

 

[gavin]

If everything else in the drive line is good, I'm betting on an out or round tire or a bent rim.

out of round tire/rim or bent rim will be noticeable 99.9% of the time.

 

[BleedFordBlue]

You might have a bit of roughness in the engine...Mine seems to have some roughness too on acceleration....all other times it's fine...it feels like it's in the engine.Do you feel the vibration through you're steering wheel,or in the seat of you're pants?

 

[flewism]

Everybody in the vehicle can feel this shutter, it is a that severe. My fear in that I will end up taking it in and be chasing this problem for an extended period of time, costing major dollars. Like i said in my first post, My plan was for my latest new driver in July, then to be 16 year old son to start with this vehicle. I could start driving it daily myself, and hoping it gets worse and then isolate the problem.

 

[gavin]

ohhhhhh you know what?
now that I think about it...

since you have the V8.

does it happen only with O/D ON? or does it also happen with OD off?

When I first purchased my truck, used, I had a shudder that would happen only with O/D on, going around 35-40mph. If I left O/D off, it would not happen.

Turned out to be something with the transmission, that was fixed under warranty.

test that out... see if it only occurs with O/D on. If it does, then it's likely that's the culprit. I'm pretty sure there's a TSB on that.