Shift Vibration? Feels like rumble strips!

[InkWax]

My 98 AWD v8 XLT runs smooth as a whistle...for the most part... the X has 262k on her and just recently she has started to (only occassionally) make strange noises/vibrations...

Typically when shifting from 4th to 5th (although I have read that AWD V8 98's only have a 4-spd auto???) the X feel like it is hitting a bunch of rumble strips in the rear end.... though very seldom it does happen in other gears and VERY VERY seldom it happens when downshifting... most of the time it happens from 50-60 mph and around 2-3krpm.....and only while accelerating...

I have been looking and I have seen its possible U-joints...driveshaft....maybe even shocks/leafs?

My father did drive it hard with lots of weight in the rear of the truck for almost all of its 260k....usually between 1k-3k lbs of weight.... I am waiting for my replacement RS9000x shocks to come so I can bolt them up....but I am worried that maybe it is something more than just the shocks..... Leafs wouldnt be too bad....but I am hoping that it isnt a serious problem...

If anyone has any suggestions can ya toss em out??


Thanks all.

 

[mx_racer_14]

I know this seems really simple, and you may have already tried this, but sometimes on my own vehicles they will do this when the tires throw weights and they are really out of balance. although what your describing sounds worse than what i've experienced it's worth a shot if you haven't tried it already.

 

[Jason_25]

Your explorer is only a 4-speed automatic. It doesn't have a fifth gear. Anyway, what you are experiencing is a symptom of loose valve body bolts in the transmission. Drop the pan, tighten them hand tight, and you should be good to go.

 

[InkWax]

Well, then how come when I accelerate it seems as though it goes through 5 gears??? Or am I halucinating one of the gears? Could it be the O/D?? Or am I mda/dumb???

Could it be the valves in the tranny even though it feels like it is coming from the rear of the truck?? I thought maybe it was the (I dont know much about the X's so bear with my stupidity) rear diff or something?

Thanks all

 

[Jason_25]

You're feeling the torque converter lock up.

 

[97emerald]

Try a trans fluid change. My wife's Cougar had the same problem and when I changed the tranny fluid, the problem disappeared. I think the additives in the oil wear out that enable smooth shifting.

 

[InkWax]

Emerald and Jason thanks....

Finally got the X into the shop and had the fluid replaced......man she rides like a dream now.....

Only had her back since last night but on the drive to work I almost didnt notice the X shifting.....and with 262k on the X thats amazing.... (course the tranny lasted 220k before needing to be rebuilt)....Now to figure out if there is a way to make the engine purr a little better.

Again thanks Guys....

Now onto switching out the stock shocks