jeff48

Hi, first post on ClubLexus. I searched the GS sub-forum to no avail.

I was wondering if anyone else has experienced these issues. The car has 213,xxx miles. When in D or R, stopped with the brake pedal pressed, there is a very noticeable vibration with and without AC on that is worse when it is cold outside and when the engine is cold. This vibration rattles parts of the interior. There is also a noticeable THUD when the trans shifts into 6th gear. Typically, I will accelerate to 45-50 and then release the gas and press the CRUISE SET. When the transmission re-engages and catches 6th gear there is a thud on the floorpan. I have narrowed my search down to the engine mounts, trans mount or the differential bushings. I have visually inspected the motor mounts and they seem alright (hyrdraulic mounts?) and the trans mount is not torn or cracked. I haven't looked at the diff bushings but this seems like the most likely culprit for the transmission engagement thud.

If anyone has experience with these issues and resolving them, feel free to respond with some knowledge!
Thanks

myzilla

tghw

That sounds more like a torque converter issue than a motor mount issue to me. 200K+ miles? Have you ever had the trans fluid flushed or replaced? That can also cause problems if not performed. Lastly, there is a problem with the trans ECU that has been identified and there is a source that will repair it for less than $200. You need to do a better search for trans issues. Try searching in the "Maintenance" forum. There are several extensive threads that address this kind of problem and how they were fixed.

potatomon

mines butter smooth at 220k except for when i dont press on the brakes hard enough and the car tries to drive away in D, that can cause a big shake.

Other than that change the fluid.

the reason it shakes when cold is because the engine revs at higher rpms like 1500 and when you switch to D of course it will give much more of a thud than if it was at 900.

the rpms drop after like 20 seconds of idle so I guess try that

jeff48

Wanted to update this post.

I got my engine mounts and transmission mount replaced. That completely resolved the idle vibration issue.

However, I still have the P,R,D engagement clunk. This clunk also occurs when I disengage cruise control for a few seconds and then re-engage it, but it is not as noticeable in that situation. I'm sure it is the diff bushings since it happens when the driveline changes directions (R&D) and when initial torque is applied to the driveline (P to R and P to D, and sometimes gear shifts and throttle engagement). I inspected the differential bushings and they are cracked and sagging. The bushings for the front (pinion end) of the diff can be purchased from Lexus and the rear bushings can be purchased as well but the removal and installation of these bushings seems to be the real kicker here. The front bushings have to be pressed out of the differential assembly and the rear bushings have to be pressed out of the subframe. This is no small task and not something that I'm willing to attempt at home.
Has anyone else had their differential bushings replaced?

DEREKC

Jeff,
I have the same 06 GS430 and the whole car vibrates when engine is idling. I took out the transmission mount. It was bad and I put in a new aftermarket one. Vibration still there (or worse as now the vibration goes thru the 2 bad engine mounts?). Next is to replace the 2 engine mounts and I am trying to DIY. Question if you don't mind. Did your bad engine mounts show any visual damage before and after you took them out? I looked at mine and don't see any torn and hesitate to take them out. The design of this makes it impossible to show if it is torn inside? How hard is it to replace? Jack up the car to crawl under, jack up the engine (with a piece of wood) at the oil pan so as to relax the mount, then loosen the 4 bolts of the bracket above the mount, and 1 bolt of the mount stud, then you have room to take out the whole thing? Or you need to loosen the subframe or remove the sway bar?
There are not many 2006 GS430 out there. I could not find much info about removing the engine mounts. Transmission mount was easy.
Your input is appreciated.

Moisture

You need to drop the pan filter and have it replaced or at the very least clean out the existing one and put transmission pan magnets into the bottom of the pan before you reseal the gearbox.

You've started damaging your shift solenoids which is why the shift into sixth gear is rough, so you'll need to drop the pan to access and replace the faulty ones as needed. Find a good mechanic or transmission shop in your area.

Dont drive your car until you get the pan dropped.

jeff48

Derek,

I did not replace them myself. I was lucky to speak with a technician at my local Lexus dealership who offered to do the job “on the side” at a discounted rate so I jumped on the opportunity. My engine mounts showed no signs at all of wear and tear but when removed, the tops of the mounts were completely broken off from the rest of the mount. I’m not sure how much mileage you have but my gs430 started to idle vibrate (due to the hydraulic fluid mechanism in the mounts degrading) around 160k miles.

I have done some very extreme mechanical jobs at home previously but I had no confidence in being able to do the engine mounts on this car in my driveway. The technician said he unbolted the whole front subframe from the car, dropped it and held the engine in place with a large table-esque trans jack.

DEREKC

My car has 220K. I just bought it with a bad ABS actuator. Now that was fixed, I noticed the vibration. Then replaced the bad tranny mount. Even more vibration.
Good to know that, before removal, these mounts would not show signs of wear and tear. That gives me confidence to proceed. Afterall, our engine + tranny are supposed by 3 mounts. What else after replacing the tranny mount, right?
It looks like there is a metal bracket on top of the mount. The bracket is bolted to the engine by 4 bolts, then one bolt to the top of the mount. The bottom of the mount is another bolt to the subframe. Very tight there. It will be hard to get access to these bolts and nuts. I will report back what need to be removed to get that thing out, hopefully with pics.

ibidu1

iTrader: (1)

Anytime you do mounts, its best to replace them all at once. Because say you have 3 mounts on the car with all at 100k miles on them, then the transmission mounts goes bad. When you replace that 1 mount, you will still have the loose play of the other mounts. That play will quickly wear out your brand new transmission mount. So its always best to replace them all in a complete set.

As far as the thud, did you check the play in the driveshaft? Maybe you have a guibo going bad or u joint going bad. Raise the car in the air with one of those 4 post car lifts. Grab the driveshaft and spin it by hand back and fourth until you see the slop on the drive line.

DEREKC

It seems like removing the sub frame is unnecessary, I just took out the passenger side mount pretty easily. With the engine not jacked up, unbolt the screw at the bottom of the mount that attaches to the sub frame then jack the corresponding side of the engine until the mount's screw is clear of the sub frame. Then remove the 4 bolts connecting the engine side of the mount to the engine. With some elbow grease and moving around some wires we were able to get it out.







Seems simple enough but from the photos provided, could you guys point out the "bad" parts of the mount? Seems that the only rubber portion is where the screw hole is and inside the metal "casing". I don't see any excessive cracking, what are the telltale signs of a bad engine mount? Is mine needing replacement? Thanks!

ibidu1

iTrader: (1)

Its hard to tell with sealed hydraulic mounts, but you can tell when they are in the car. What I like to do is, engage the handbrake and put the car in gear with the hood up, a tap on the accelerator pedal gently. If the mounts are good and tight the motor will lift slightly, if they are worn the engine will jump. I also do this in reverse gear, as it puts force on the opposite side

DEREKC

Ordered and waiting for 2 OEM engine mounts to come. I don't want to hijack this thread and will start a new one with subject "GS430 V8 transmission and Engine mounts change - DIY" and will share as much info as I have learned. Time to me to contribute. Give me a week.