I didn,t know what to call the prob I am having with my 97 lx450 so please dont kill me for not finding info through the search.

97 LX450
139k
New shocks Pro comp es9000
All maint has been done
do not know if knuckles have been touched
bought 1000 miles ago
Tires balanced

Truck drives great till about 75mph then starts to shake and feels real bumpy like bad shocks. Calms down around 80 then starts again at 85 any Ideas

 

Sounds like a bad balance, or a bent wheel. Could also be wheel bearing, or even...*gasp* check those lug nuts, got to love the old loose wheel syndrome...

 

Wheels slightly bent or just don't drive 75mph.

 

I dont think the procomp shocks are best but dont think they are your problem. What size tires? Like others have said sounds like your tires are out of balance.

You could also check your TREs. Tie rod ends

Is it a side to side shaking or a up and down bouncing?

 

Did you ever find out what was causing this? My buddy just replaced all four shocks on his 96 Landcruiser with Bilsteins. Now has a very noticeable side to side rocking at around 75 mph. His bro is telling him it is the Bilsteins not being heavy duty enough for the vehicle, which I know is not the case. Any ideas? TIA...