nikolai00

Hello, I am new to forum here and this is my first post after doing some searching and not finding a similar scenario to mine. I apologize in advance for my lengthy post....

My wife's 2007 RX350 AWD has a few issues, which may or may not be related to each other. She has had the vehicle for about 5 years and it currently has around 125,000 miles on it and has shown no other major issues to date.

1) There is a slight vibration felt when the car is idling in either drive or reverse. For example, at a red light you can feel it just a bit. This becomes much more pronounced if putting the car into D or R immediately after a cold start. When it is very cold (upstate NY cold) on a cold start, it will actually rattle some panels inside the car.

2) When cruising along (at any speed really I've noticed) the vehicle feels like it's pulling back slightly when the gas is released. Of course it's not accelerating because I'm not giving it gas - it's more like if you were to drive a manual car around in 2nd gear, it would be pulling back. This is ever so slight (My wife, as the main daily driver of the car, didn't notice this herself)

3) When braking to a stop, there is a slight shudder or pulsing. The steering wheel does not shake. I realize this could very well be the rotors (only 15K miles on them) but when rotors were bad on our other vehicle (2005 BMW X5) the steering wheel would noticeably shake in this same scenario.

When I described issues (1) and (2) to my trusted mechanic he was led to believe that it may be symptoms of a torque converter that is on its way out. Maybe (3) could also be related to the above issues, but I'm not sure.

I see Dacco torque converters online for about $150 but I was quoted at 15 hours of labor to replace this relatively inexpensive part - as I understand both the engine and tranny have to be dropped from the AWD model. I'm not opposed to putting that kind of money into the vehicle if I knew it would significantly extend its life, but I want to be fairly certain that it would actually fix the issue(s) above. My next step will most likely be to bring it to my mechanic for a proper diagnosis.

Has anyone else experienced any combination of the above issues or does anyone else have other thoughts on what the source of the issues may be?

Thank you very much and I look forward to my time on this site!

Nick

smassey321

I would check the motor mounts first.

robbyk

Nicolai00,

I just had an experience with issue number 1 above - There is a slight vibration felt when the car is idling in either drive or reverse - on my wife's Toyota Corolla. Any time she came to a stop and the vehicle was in drive or reverse - when she was backing up from the driveway - we could feel the vehicle vibrating. I took the car to my certified Toyota mechanic and he found one engine mount completely collapsed, the other engine mounts were cracked. There was also a transmission mount cracked. He replaced the engine mount that was completely collapsed plus the ones that were cracked and the issue is gone. The car feels extremely smooth, just as before.
When a vibration is present when the vehicle is in idle one of the most common cause is the engine mount or transmission mount.

On issue number 3 - When braking to a stop, there is a slight shudder or pulsing - we had same identical problem with our RX330. The steering wheel was not vibrating when coming to a stop but I could feel the same pulsing you are describing we found out the rear rotors needed to be turned. Brake pads were half way gone so we decided to replace them at the same time - problem solved.!!

My recommendation to you is to take the car to another shop for a second opinion before you pour all of that money in a torque converter you may not need. If you decide to take the car to another shop do not tell them what your trusted mechanic told you. Even if you have to pay $100 for a diagnosis it is well worth it. But it really sounds like your engine mount.

On issue number 2 I would wait to correct issues number 1 and 3, once you have those issues corrected take the vehicle for a spin to see how it feels.

nikolai00

Thank you both for the advice, especially robbyk's very detailed response - I will certainly follow up with it and post my results!

robbyk

Yes please, let us know what you find out. I am curious of the outcome of this issue.

Band

Its always a good idea to investigate the cheapest fix first - in this case the motor mounts.

AussieAuto

Nikolai00

Very unlikely a torque converter problem, when you first start up the vehicle and it is cold the idle will be higher (fast Idle) and to put it straight into drive or reverse is loading the engine and because it is cold the engine mounts and transmision mounts and sub frame mounting etc are all cold too which causes them to be stiffer/hard and of course give a vibration! I have never seen a torque converter problem with one of these! Don't be to picky remember it is still a mechanically made machine.

With the brakes, well if the vibration happens at highway speeds and in steering wheel then it would be the front discs, but if it is happening just as you are coming to a stop and you feel a surging in your seat then it is the rear discs.

Hope this helps...

nikolai00

Thanks again for the good advice fellas, I'm having a closer inspection on Friday.

robbyk

Update this thread with the results of your inspection.

nikolai00

Just so I get this straight for myself - are these the mounts that are on the AWD vehicle?

*engine mounts:
- passenger
- upper shock mount

*auto transmission mount

Thanks!

robbyk

Nikolai00,

The schematic for the AWD RX350 calls for a front Engine mount, left hand side engine mount, right hand side engine mount, rear bracket engine mount plus the transmission mounts.

nikolai00

Do you have a link to the schematic/diagram or to a site where I can query the information? (such as realoem.com for BMW) Thanks again.

Think I found it: https://www.parts.com/index.cfm?fuse...iagram=8913187

robbyk

Yes I have a link,

Please follow this link: http://lexus.sewellparts.com/oem-cat...X350-2007.html

AussieAuto

Don't forget the front mount is an active mount, which is oil filled. The oil will be thicker when it is cold and it will feel more solid, check vacuum lines to mount and check mount for oil leaks too. You could get your mechanic to do an active test on the mount, just to make sure it is working...

neelnaik

I agree with the others.

Torque converter issues sounds very highly unlikely.

I would check engine mounts first. It also sounds like you need new rotors (or need them turned at least).