HELP!!!!

My 1990 LS400 has 170k miles on it. Just recently, my rear end has been vibrating at high speeds. It is intermittent and my mechanics have had trouble replicating it on their test drives. When I slow down and then stop, and then set off again at low speeds, the vibration goes away. But when I go back to 50+ MPH there it is again.
The first time it happened, I thought I had a flat tire. Then I thought it might be a wheel bearing but they now tell me they believe my ABS is switching on when it shouldn't be.

Can I just disable the ABS and do without it? I don't feel I need ABS but don't want to do anything dangerous. If it's OK to disable, how do I do that?

Thanks for expert feedback from the gurus out there!

Just to test pull out the ABS fuse....but why not get it repaired, especially on a big heavy car

I took a gamble and bought an underused low mileage 1992 LS400 with apparent warped discs. Horrendous vibration quickly developed through the transmission on braking - even the shift lever was jumping about, and quickly escalated to dramatic extent without braking.
After lots of checking plus new discs and pads that didn't cure it, I found that the rear calliper pistons had corroded so were seizing in the seals and jamming the back brakes on.
I reckon that this caused the abs to keep cutting in even when not braking as the rear wheels were always just short of locking.
Anyway, new rear caliper pistons and seals completely solved the problem.
Incidentally, I found similar corrosion in the front calipers and did same to them - completely cured dragging brakes there too.
Peter

if it was your brakes dragging, the wheels would be red hot...try taking out until it happens again and coast to a stop, feel your wheels, if they are hot, then it could be the brakes..........

the other thing it could be, is the propshaft bearing, or coupling allowing the prop to throw itself off center above a certain speed and remaining that way until you come to a stop...(assuming the LS prop is in 2 sections with a center bearing, or has a rubber propshaft to gearbox coupling like a lot of big RWD auto's)

I think you might need to read his post again.... he's already fixed it ...

i was replying to kratbomc not petertf

OOOps .... my bad