This is what I know: The Tranny noise sounds like a actual grinding noise that is eminated from the center consol of the vehicle. The noise is very quiet, but very audible when the radio is off, windows are up, and the air conditioning is either turned off or very low. You can only hear this noise when the vehicle is in motion (drive), and it is only noticable between the range of 35-45mph (Sometimes you can hear it slightly when the car is shifting as well). To make the noise you must push the gas to the point of maintaining a certain speed (like staying at 45 mph). You hear it only when you push the gas or let off of the gas (to the point of making the car accelerate or decelerate.) If you hold the gas pedal at the right RPM range and at the right point you can make the grinding continuous.

The second sound I am hearing is also coming from the center consol. It sound as if something is thumping inside the tranny. You can only hear it when accelerating from 10mph to around 30mph. The noise definatly follows with the movement of the vehicle because you cannot hear the noise when the vehicle is in park and does not change when you shift to neutral while driving. This noise has become noticably louder.

I am having the Toyota Dealership put a new Tranny and T/C in again to try and fix the problems. I will keep you updated on any progress. (i'm 400 miles away from the closes Lexus Dealership or I would have them do the work).

 

the fact that it only happens in the 35-45 MPH range really makes me think it's the torque converter... does it feel almost like you're going over a rough area of pavement? Torque converter sounds like a good start.

Keep us posted...

John

 

The car drives sluggish sometimes, like there is a vacume leak, but it doesn't do it all the time. I believe the Tranny grind is always there, but only audible between 35+mph. The car does feel like I am going over small bumps during normal driving. I'm also hear what apears to be a slight whinning sound at all times. Might be normal though.

I will find out more tomorrow when they pull the tranny.

 

Those symptoms are exactly what I experienced before replacing both motor,and tranny mounts.
That visit to the dealer was pretty much a disaster,but maybe they helped me out by finding that one.

 

Well, they pulled the tranny and determined that a Bolt that holds the T/C to the Tranny was becoming unthreaded. They had to order a new bolt for the car, it will be in Friday. When I bring the car to them I will ask them to check and replace, if need be, all bushings and mounts. Thanks For the Help

 

Well. the bolt didn't fix the problem..... More trouble shooting ahead for me

 

I had the same whirling noise on my 1992 SC 400. Dealer relpace the driveshaft bearing and the noise went away.

Never heard about U joints seizing up. How can you tell if the U joints need to be replaced? Any particular sounds??

 

The Whirling noise you heard, did it sound like something was thumping around inside of the tranny really fast? or did it make an actual whirling noise?

 

I had the thumping from a hard start, just as I had in other cars which used the same type of flexible coupling in the driveshaft.
It seems that the large rubber coupling met the floor sheetmetal slightly under torque,bumps.
The whirring or grinding puzzled me the most and was caused by the same thing causing the other noise.

 

How much did they charge to you replace that part?

 

I had similar noise, it was drive shaft bearing, entire drive shaft replaced, noise went away.

 

I had the same noise on an sc4 and it was drive shaft bearings

 

I have the SAME exact problem with my SC400. Its a 95 and I get that same grinding sound at about 50MPH maybe at a little slower speed like 45. The RPM ranges for that sound to happen it at about 2000. I sounds like something is spnning and its 2 metal peices grinding. Its the most annoying sound in the world. It seems like this problem is becoming common though. I wonder what it could be though.

Here is my post.

https://www.clublexus.com/forums/sho...threadid=58964

 

I replaced my Driveshaft and Bearing twice with brand new units and they did NOTHING... I have taken it to the Lexus dealship in Charlotte NC (Hendricks) and they couldn't figure out where it was coming from..

I get two noises..

1: The Grinding at around 45mph

and

2: The fluttering noise while hold the car at 35ish Mph

and once again.. my replacement of the Driveshaft and Center Support Bearing did NOTHING.. They were BOTH NEW from LEXUS

 

I just got my ride back 2 days ago for a repair, and upon receipt the day after,... I noticed a metal to metal sounding noise under acceleration, and in that mph range.

So of course I took it in this morning, to find out my heatshield had cracked right at the bolt and it was vibrating and clattering from the exhaust pipe resonation. Glad it was minor,...but I thought from the sound of it, it was gonna be serious.

Just a consideration.

This noise occured only when driving yesterday and this morning when I started it up,.. more more noticeable when driving, and as you said,...could only be heard if my music was off, and i listened or rolled the window down.