Whirring sound at very low speed.
 

Ever since I've had this 96 LS400 (maybe 2 months now), it's had an intermittent sound at very low speed. I'll try to describe it.

It's a quiet but noticeable whirring whoop whoop whoop kind of noise, without the "p". Medium high pitch, and not a whine. It seems to be coming from the front right somewhere as you're in the driver's seat, though it's hard to tell for sure. It's present on deceleration and acceleration at VERY low speed (like 5 miles per hour, or even less).

Oh, and sometimes it's not even present.

A strange noise in an otherwise real solid car. Not sure what could be. Hope it's not the torque converter. Any ideas? Thanks!

Wheel bearing maybe?

That would be awesome if it was so simple. It's tricky to isolate, and tricky to describe or record. I'll check into the wheel bearing, and once I figure out what it is I'll definitely report back. Depending on what it is, it may take a little while to figure out.

Thanks for the reply!

I suspect it's the tires.

Jack the vehicle up and try to spin the RF tire and see if you hear any noise or feel any looseness by shaking the wheel. If you still don't hear anything, take the tire off, undo the brake caliper and remove the rotor, then spin the hub/bearing by hand and see if you feel any roughness when moving it.

I replaced mine at 280k thinking they were bad but they really weren't. I did them both since they were 20 yrs old and the grease had most likely been used up also just due to mileage. I figured they were worn out and I did hear my RF wheel get louder anytime it went over a dip in the road so it could've been time. I first swapped a JY RF knuckle for 30 bucks to test it before I spent the time pressing them in and out, and it confirmed my thinking, the noise did improve a bit with the low mileage JY knuckle and bearing.

I'll do that next time I get a chance. I'm exceedingly busy most of the time anymore, but once this is solved, I let you know. It's a new sound for me in the automotive world.

Like a higher pitched version of The Jetson's "space cars"(old school stuff, for sure) accelerating or decelerating.

I suspect the tires too. check for uneven wear. common is a bad strut rod bushing where it throws off the alignment and starts feathering the tires causing unwanted road noise. if not, then wheel bearing is next and check your brakes/calipers to see if they are getting stuck shut.

Actually, I think I might know now what sound you're describing. Almost sounds like an electronic whirring sound that you can hear in the cabin when the car is creeping along right?

My 97 does this too. I'm thinking it might be Transmission related, something with the mesh of the gears, would be my guess causing that whining noise that disappears after 5mph.

I actually kinda like hearing it, almost reminds me of a Tesla with it's electric motor and direct drive Transmission noise. But I know these cars are supposed to be silent, so any noise is probably something to troubleshoot.

I'll double check my fluid level and see if that's it. I did a couple of drain and refills along with replacing the tranny filter and lock-up solenoid in the past couple months, so it is a possibility that the level might not be where it should be at.

I'll check all that, I believe my strut rod bushings as well as all the other bushings in this car are pretty much done, so you could very well be right. We'll see...thanks!

Yeah, it's a strictly low speed sound, though it's not really a whine at all. It's more pure, clean.

I've had my ATF level slightly high, slightly low, and right on the money, which is where it's at now. It was a little tricky getting it just right without being familiar with the car. Sounds the same regardless. Seems possibly torque converter related. I haven't had time to check it out, so the car does a lot of sitting around. Tomorrow I'm dropping the transmission pan and replacing the strainer. We'll see what's in it. Could be....interesting.

How long has yours been doing this?

The same thing has been going on intermittently with my LS. The only commonality I see between each occurrence is that the sound is only present before the engine warms up. I recently topped off my transmission fluid level and no difference. Still get the sound from time to time but a lot less than before my timing belt change.

I'd say since I started doing the drain and fills of the tranny fluid, so back in Oct 2016. I've put on maybe 8k miles since then and it drives the same. Before I had some hard shuddering due to my lockup solenoid so it could've been there but that lockup solenoid was masking it.

Yeah, its definitely not an unpleasant sound, sounds very mechanical and pleasing to me so I didn't really do anything about it haha