Sc400 Vibration Shudder Always. . .park And Drive

[Micah]

Hi,

I just purchased a 1996 Lexus SC400 with 204000 miles. The problem is that there is a vibration in the car both at park and in drive that varies with RPM. Idles very smooth, no check engine light, very good power (but not tire squeeling power). When I rev it with the gas pedal, there is a distinct shudder inside the car both in park and in drive. It comes and goes at various RPM. If I rev it from the engine compartment, I can feel no trace of it in the motor, so I assume it isn't the motor doing it. Here's a list of things I have done to the car:

Changed Spark plug wires, distributor caps and rotors. . .b/c there was a miss in cyl. 5 and 7

Changed Brake pads (front)

Have not changed spark plugs yet, but plan to do so with next pay check (wires, caps, rotors, and brakes set me back several hundred dollars even though I did it all myself)

What could be causing this? My first instinct tells me it could be the torque converter, but I'm not sure. Also, the car seems to cruse at somewhat high RPM. at 55 its at 2000 rpm and at 75 its at 2700 to 2750 rpm. This also leads me to believe that it might be the torque converter as my grand prix v6 does 75 around 2400 to 2500 rpm. Not familiar with this type of car, though. It may just be normal; I don't know. Any help on this would be appreciated! Thanks!

PS: sorry so long winded, I just wanted to be thorough. Thanks!

[jzz30]

motor and trans mounts!

i havent tried this but you can try slide a small jack under the car and lift the motor and trans up an inch and hop in the car and see if it vibrates. assuming that the car vibrated even with the car not moving this may cure the vibration making it 100% engine and trans mount faulty.

[Micah]

motor and trans mounts!

i havent tried this but you can try slide a small jack under the car and lift the motor and trans up an inch and hop in the car and see if it vibrates. assuming that the car vibrated even with the car not moving this may cure the vibration making it 100% engine and trans mount faulty.

I will see if the toyota dealer can test the mounts on Tuesday as I don't want to damage anything. I am going to get them to change water pump and all belts (tune up) as I don't know when the last time it had a tune up. About the rpm though, is 2700 rpm normal while going 75 mph in these cars? I am not familiar with them and wanted to know. That would tell me if I'm having any transmission trouble (although it shifts pretty well for a car with 205000 miles). If I get down on it, it shifts pretty hard, but smooth if I ease down on accelerator. I can barely tell that the torque converter is locking. Thanks for the reply!

[jzz30]

yea the rpm is normal. im pretty sure its the mounts though.

[Micah]

yea the rpm is normal. im pretty sure its the mounts though.

Thanks for the reply. I believe you are right b/c I can feel a clunk when I put it into gear. I noticed it after you mentioned the mounts.

[Oakridge 52]

Hi,

I just purchased a 1996 Lexus SC400 with 204000 miles. The problem is that there is a vibration in the car both at park and in drive that varies with RPM. Idles very smooth, no check engine light, very good power (but not tire squeeling power). When I rev it with the gas pedal, there is a distinct shudder inside the car both in park and in drive. It comes and goes at various RPM. If I rev it from the engine compartment, I can feel no trace of it in the motor, so I assume it isn't the motor doing it. Here's a list of things I have done to the car:

Changed Spark plug wires, distributor caps and rotors. . .b/c there was a miss in cyl. 5 and 7

Changed Brake pads (front)

Have not changed spark plugs yet, but plan to do so with next pay check (wires, caps, rotors, and brakes set me back several hundred dollars even though I did it all myself)

What could be causing this? My first instinct tells me it could be the torque converter, but I'm not sure. Also, the car seems to cruse at somewhat high RPM. at 55 its at 2000 rpm and at 75 its at 2700 to 2750 rpm. This also leads me to believe that it might be the torque converter as my grand prix v6 does 75 around 2400 to 2500 rpm. Not familiar with this type of car, though. It may just be normal; I don't know. Any help on this would be appreciated! Thanks!

PS: sorry so long winded, I just wanted to be thorough. Thanks!

[startacus]

Mine - similar vibration - The culprit was the transmission mount however I went on and replaced the motor mounts as well while they were under there. ;)

[Thomas A. Iglesias]

Mine - similar vibration - The culprit was the transmission mount however I went on and replaced the motor mounts as well while they were under there. ;)

My 1996 SC with 86,000 miles had the exact symptoms. Change both the engine and transmission mounts and the car will be glass smooth. Well worth the $$.

T.I.

[UCF3]

Wow. This is gotta be the most common question asked on this Forum. Jzz30 I'm going to Pin this Forum.

[lemaylexus]

can someone post in this thread the exact part numbers that are needed if one was to replace their tranny mounts and engine mounts? i would be most appreciative.

[305pimpc]

can someone post in this thread the exact part numbers that are needed if one was to replace their tranny mounts and engine mounts? i would be most appreciative.

TO CHECK THE MOUNTS YOU NEED A FRIEND AROUND!

START THE CAR OPEN THE HOOD HAVE YOUR BUDDY PRESS THE BRAKES AND PUT IT IN REVERSE THE REV IT WITHOUT LETTING THE BRAKES GO KINDA STALL THE CAR AND SEE IF IT MAKES THE MOTOR JUMP THEN DO THE SAME IN DRIVE IF YOUR MOUNTS ARE GOING BAD OR ARE GONE YOULL SEE THE MOTOR WANNA JUMP OUT OF PLACE! HAY IM NEW HERE BUT NOT NEW TO CARS TRY IT OUT!!!! ;)

[UCF3]

TO CHECK THE MOUNTS YOU NEED A FRIEND AROUND!

START THE CAR OPEN THE HOOD HAVE YOUR BUDDY PRESS THE BRAKES AND PUT IT IN REVERSE THE REV IT WITHOUT LETTING THE BRAKES GO KINDA STALL THE CAR AND SEE IF IT MAKES THE MOTOR JUMP THEN DO THE SAME IN DRIVE IF YOUR MOUNTS ARE GOING BAD OR ARE GONE YOULL SEE THE MOTOR WANNA JUMP OUT OF PLACE! HAY IM NEW HERE BUT NOT NEW TO CARS TRY IT OUT!!!! ;)

305Pimpc:

we really don't use capital letters on the forum. So for future posts please be mindful of others and take the Caps Lock off.

[btc]

I've also seen a similar vibration problem in my SC400. It's a '93, so chances are these engine/trans mounts could use some replacin' by now...

Anyone know about how much to expect for this type of service?

(A lot of times if you walk into a garage for an estimate for a "non-essential" repair like this, they see it as a green light to warm up the shaft for you...)

Cheers!

[RIVERAT]

Mine is a 95 model and I notice a slight vibration, a dull roar, when reaching a speed of 55 or 60. That is where it begins. It almost sounds as if it is below the shifter or console in between the seats. If not for this noise, the car would be very quiet. I plan on taking mine in for inspection and will let you know what it turns out to be. Thanks to all before me, that posted possible causes, so us new members have somewhere to start.

[BenLEXus]

Just took the mount off my 1992 yesterday due to hard parked gear selects and little bumb when switching to overdrive, and some vibration in overdrive at low speeds. It wasn't broken put stock has A LOT of play, i can move it just by twisting, but was still all together. Got the idea from Club Lexus forums to reinforce with high PSI epoxy, two part mix together nasty stuff. I will post pics of the whole procedure if desired. It was super easy even for a garage dummy like me. Didn't fix my prob, must be motor mounts, eh. Did notice a nice difference in shifting and direct throttle from epoxy.

I'll take it back off to do the motor mounts and see if it holds up and possibly put another layer of epoxy in the gaps.

About service times, it took me on ramps lying on my back lifting up trans pan with scissor jack from trunk and not able find my tools after i lay them down 30 minutes of actual labor. And thats with me being really unorganized and not a good mechanic period AND cleaning to dog s**t out of everything. Hope that helps.

[BenLEXus]

I really don't want to pay $300 for megan mounts. Anybody know a GOOD place to get oem front motor mounts?

I tried Autopartswarehouse.com and was charged and then refunded a few days later with no notice or explanation. I then contacted Partsgeek.com and was called by a real person who assured me at least 2 were in stock. I made my order and within 15 minutes received an email explaining the part is not in stock and i would be refunded. WTF!

I don't want to pay dealership $100+ each but is that my only other choice? Any comments or local dealerships that are not scam artists would be greatly appreciated.

[lexuskid94]

the engine will jerk some whenever im going up a hill at rpms ranging between 1000-1600. could this be the mounts?

[Servidor]

OK... I'm new here but this is an awesome site for me. How many mounts does the SC400 have? Engine and tranny included. I'm gonna replace them all.

[Portugee420]

I ran into somewhat the same issue... my engine/trans. ran fine, fluid levels set and ok,no mil,my drive shaft bushing/coupler assy worn/torn, trans. mounts worn, replaced trans. mounts and "dampner" located on rear of driveshaft. drained and re-filled diff. fluid and road tested, vibration still there, worse when OverDrive Disable was disengaged,re-inspected vehicle on hoist, found rear differential assy (spider gears) causing abnormal vibration/shudder even with eng/trans. ok/ no mil on, after replacement of rear differential carrier assy, (upgraded final gear ratio 3:55) car rides like it was brand new.. hope it helps to solve your current issue and/or help anyone else...my works done..lol

[MrLatifa]

Ouch, how much was the parts cost on rebuilding the rear diff? My car (just bought) is suffering from a slight vibration or two. It had the usual misfire from overdue wires and plugs ect.. Then after new tires, less vibration. THEN after new lower control arm bushings...no change. Still feeling a vibration when under light accleration in motion at 1800-2200rpm, I am beginning to wonder if the rear diff in mine is going out as well. I can feel the rolling vibration in my seat and not the wheel as much. This would indicate it is more rearward? Anyhow, I wanted this car because I expect it to run like silk. So, Ive also bought new straight wheels, and am sure Ill be putting in the factory HYDRAULIC engine mounts and transmission mount. The kicker, the car vibrates at that same rpm while in park, however the vibration is more cyclic, with a sec between cycles. Ive been a tech for many years, and Im thinking that the confusion is arising from multiple vibrations. Anyone else maybe experiencing the same odd combination of symptoms? Im going to support the engine and isolate the engine mounts from the equation, tomorrow. I'll also try to listen to the rear end as its in the air. Just hope to nail this down before i replace everything. Im sure the parts add up, and torque convertes aint cheap. Ill let you guys know.

[MrLatifa]

Lightly supported the engine by the oil pan and free revved the engine, to find the dreaded shake thats most apparent around 2k rpm. TOTALLY GONE!! As I lifted the weight off the engine mounts, I noticed seperation showing between the mount and the engine mount bracket. I am suspecting that over the last 20yrs, the mounts have fallen flat and are allowing the engine to resonate thru the car. The sound is cyclic, so maybe the car is amplifying the vibration in waves. Anyhow, being soooo excited about it feeling silky smooth, I ordered 2 hydraulic factory engine mounts. Hopefully in a week, Ill be able to post that I'm a VERY happy Lexus owner....

11/13 Still shuddering after new mounts. After taking bad advice and starting the car with the torque converter unbolted, I heard a brief metalic niose, and then the vibration. After rebolting the converter, the shudder got worse, and a slight noise from the bellhousing could be heard. Decided to remove transmission and found this.... Good news, found an issue. Good news, transmission only took 2 hrs to remove. Bad news, parts aint free, worse news, the pilot is stuck in the back of the crank. Im thinking either drill and use a slide hammer, or... weld to it and use a slide hammer. Either way, its getting a new rear main seal. Since the vibration was nearly the same, only worse, I'm hoping that replacing the torque converter and getting a straighter flexplate will be the end of that. I notice that the rear main is newer than the car, and the transmission looks to have had work done to it. Maybe somewhere along the line, the converter got bolted up improperly, and I aggravated the situation. Anyhow, Ill let you know what happens, once I install all the parts and get the transmission mount in. Damm good thing I dont pay myself for labor!!!

[MrLatifa]

HOORAY!! Got the piece out of the end of the crank. When I went to center punch it to drill for a tap, it actually just cocked sideways and was pulled straight out. A local torque converter shop got me a rebuilt converter for $120, and I ordered a used flexplate from ebay. After checking my flex plates for runout and balance (on a wheel balancer ha!), I ended up reusing the original and decided my purchase was a wasted $35. Upon installing the new converter and putting it all back together........smooth as a cucumber! The vibration that was giving me such a hard time is gone!! Persistence and a ton of free labor and wham, fixed!

Vibration: cyclic vibration in nuetral,park and while moving in drive. The vibration begins to be felt at about 1400rpm and increases in speed and amplitude as rpm's rise.

*note : supporting the engine from the mounts via stand/jack, only isolate the engine and transmission from the body. It was determined the vibration wasnt from the exhaust mount locations, so the support test does ABSOLUTELY NOTHING to help aid in further diagnosis. Mounts only dampen small inherent vibrations. Mounts WILL NOT stop the origination of the vibration!!

Solution: Replaced torque converter, pilot nose on old converter found to be broken, allowing slight misalignment of converter to flywheel installation. (mine was obviously damaged by the previous technician installing a rear main seal, previous owner noted vibration but ignored it for how slight it was.)

NOT SOLUTIONS: Engine mounts, transmission mounts, tires, wheels, brakes, and all that other crap. What Ive learned is that no ammount of forum reading can take the place of a well informed mechanic that has been down those roads. My first guess was in the converter, I shoulda just did that first.

Hope this helps anyone out there that has tried all the regular mounts and crap. Be sure to inspect the converter and the harmonic dampener on the front, BEFORE spending a fortune on rubber mounts.....

[1996 1uz-fe]

can someone post in this thread the exact part numbers that are needed if one was to replace their tranny mounts and engine mounts? i would be most appreciative.

ebay sells these megan mount kits, i would go for those. you just need to make sure they look like the ones yous you need, they usually never post the p/n. but you can always call a dealer, they will provide you with the corect part number if you want to buy stock mounts.

[sc400InTraining]

Regarding Engine and Transmission mounts here are the numbers:

Engine Mounts(2): 12360-50110 for $202

Transmission Mount: 12371-50030 for around $60 I think

Got my parts from ToyoLex Parts Connection, I get all my "Dealer Parts" from those guys, they are the real f**kin hookup!!

[sc400InTraining]

Forgot to mention that I am also having the same problem but for the most part taking care of the Engine and Tranny mounts got rid of most of the vibration, but the problem is still going on. If you dont decide to do it yourself, I would recommend not paying more then $250 for the job based on the inputs from the DIYs in the thread (or atleast thats what I negotiated for)

Im gonna take Hooplehead and 420's direction next. But replacing the mounts is a definate, my car rides like brand new minus the "light" vibrations still happening at Idle while the car is in drive. However between 0 and 40 mph its smooth as sh*t but when I get between 40 and 50 mph the "light" vibrations kick back in and that's with Over drive engaged. Disengaged it vibrates while idle in drive but no "light" vibrations between the 40 and 50 mph. I will update this weekend when I have time