Scraape

my 98 ls400 with 265k just developed some sketchy noise in the driveline i believe. its kind of a clunking sound that comes from under the car when i'm going 40mph or so.


car has new coilovers all around,
new front ball joints,
new front control arms,
new front strut rods,
new sway bar end links,
new tie rods except for the driver side inner tie rod which i forgot to do lol (it would honestly be nice if that was the issue).

I personally think it's the driveshaft somewhere. U-joint? Flex Disk (the rear one was the only one i could see and it didn't look in the best of shape).

The axles seemed fine, no torn boots or anything, fresh diff fluid change 75w-140 at 254k. Wheel bearings haven't been done and sway bar bushings haven't been done.

djamps

If you haven't changed the transmission mount lately I'd put my money there. You'll need motor mounts as well unless you want to change the trans mount again a year later.

Scraape

i forgot to mention motor mounts and transmission mount are new

Granite88

Seeing as you have refreshed all the other mounts, its very possible the driveshaft ujoint is tired. Is there any clunks when pulling away from a dead stop?

Scraape

there is a another clicking sound which i have attributed to being the brake shims (or lackthereof on my akebono pads). I've had that sound for awhile.

The sound i'm referencing in the video seemed to pop up after my road trip down to Tampa and back.

Seems to happen when the car is coasting around 35-40 mph and i put my foot back on the gas, makes 2 or 3 clunking sounds like it's something rotating.

Obviously i need to get the damn thing on a lift and examine everything. I haven't taken a close look at the driveshaft before but I'm aware it's a two piece driveshaft

djamps

Check the large rubber torque bushings at each end of the drive shaft?

Scraape

good call, yeah the only one I could see was the rear one and it didn't look very good honestly, so maybe the front one is even worse, I'll take a look.

valex

There is some info on the driveshaft here:

https://www.clublexus.com/forums/ls-...ushings-2.html

You would need to drop exhaust first, I kept the O2 sensors in the exhaust, unplugged them in cab under carpet.

Scraape

my car also has a kind of whining sound i've noticed now ever since I put the 18" wheels on. The whining only happens with my foot off the gas. I don't doubt it is linked to the same clunking noise i am having.

I'm thinking my issue could be driveshaft, wheel bearing or a bushing. Gonna have to check it out tomorrow

Scraape

listen to this ****....sounds bad lol

Scraape

oh boy.....found the problem!

i had changed the gear oil around 10k miles ago with OEM toyota 75w - 140 synthetic .

Originally when i changed the fluid it looked as though it hadn't been done in the life of the car (which was 255k at the time), and it had metal shavings on the drain plug from normal wear I would assume.

valex

So it was diff making that noise? I thought it would make constant humming noise when its bad, not vibration at a certain speed.

Scraape

diff was making a whining noise(which you couldn't really hear in the original video) as well as the nasty clunking sound at certain speeds on decel when driving the car.

When I put the car on jack stands and let it go through the gears that is when I diagnosed it as the diff. Sounds on deceleration were nasty when it was in the air. Put my hand on the diff on decel and it was vibrating like crazy, which then led me to drain the gear oil that only had 10k miles on it. That's where i discovered the metallic colored gear oil lol

valex

Was your pretty stable on jack stands going through the gears? I wanted to do that a couple times, but thought it might be unsafe.

Scraape

oh yeah, very stable. I was skeptical at first but then did it several times with no issues