Replacing The Tranny Mount Today

[billydpowell]

I bought a new tranny mount for my 99, and I am putting it in today.

[dcfish]

Billy, Post a tutorial if you would be so kind B)

[Micah.Berry]

dcfish,

The following is a tutorial on Club Lexus: http://www.clublexus.com/forums/ls400/450071-diy-engine-and-transmission-bushings-replacement.html

I'm curious on Billy's before and after driving impressions. Billy, is this the car on which you changed both motor mounts? I don't recall if you've changed the mounts on both of your LS's.

I am looking to change mine in about 2 to 3 weeks when I change my oil and tranny fluid. Looks fairly simple based on the tutorial above. I get a very noticeable vibration in the floorboard and seat when driving 80. What's odd is that the vibration disappears and then comes back, which I can only attribute to movement on the bushing as I apply throttle or go up and down hills. It's weird, but the slight misalignment of the drive train makes sense to me. I'll start with the transmission bushing and work from there.

Micah

[billydpowell]

OK!, jack it up put on stands, lay my blanket down and crawl under it. remove 3 bolts holding the splash pan on, put the jack under tranny with a board on it. lift tranny just enough to releive the pressure,

remove the four NUTS on bottom of mount,

remove the four BOLTS holding the crossmember to the frame.

remove the four bolts holding mount to tranny.

NOTE the position of crossmember (if not marked)

thats it...

put it all back

Micah yes this is the one I put the motor mounts on, I thought I had replaced the tranny mount, but it must have been another one.

AND!. this took the "movement" our of the feeling in the steering and seats. mine was not a shimmy or vibration, but a noticable movement that this 99 had but the other one didnt.

take a look....

[1990LS400]

I am looking to change mine in about 2 to 3 weeks when I change my oil and tranny fluid. Looks fairly simple based on the tutorial above. I get a very noticeable vibration in the floorboard and seat when driving 80. What's odd is that the vibration disappears and then comes back, which I can only attribute to movement on the bushing as I apply throttle or go up and down hills. It's weird, but the slight misalignment of the drive train makes sense to me. I'll start with the transmission bushing and work from there.

Micah.Berry, how many miles do you have on your 99 LS now? Wasn't it at 112,000 miles last Spring when you bought it here in the Kansas City metro area?

FYI, since I was experiencing a very slight vibration through the steering wheel at idle, I specifically asked that my transmission mount be checked during the 120,000 service earlier this year at the indie Lexus specialty repair shop that has been maintaining our Lexus and Toyota cars since 1996. The mechanic thought the transmission mount on my 00 LS was a long way from needing replacement so I will have it checked again at the 150,000 mile service.

IMO, it is doubtful that your drive train is misaligned. The cause of your vibration at highway speeds is more likely a wheel imbalance, a defective tire or a defective suspension component. First, eliminate the tires/wheels as a potential cause by having them dynamically balanced. If the vibration is still there, look at the suspension. I assume that you have verified that the strut rods have been replaced or that you have replaced them since you bought the car since you were involved in a discussion about them earlier this year. The strut rod bushings rarely last 75,000 miles on a 98-00 LS and sometimes are worn enough to cause vibrations at highway speeds by 40-50K miles.

[billydpowell]

hay you guys, This is what was causing the car not to be smooth at 80mph. I was having a slight movement in the steering and seats, not a shimmy or vibration, but something that should not be there. my other 99 was/is perfectly smooth, now they both are.

ALSO Micah, mine would come and go too..... at a steady 80mph, that eliminates wheel balance

I had also checked my tires, and just changed the poly-to OEM strut bushings.

the mileage on the one I just fixed is 146k, the other one has 161k, just done the starters on both, and a door actuator on 146k. I have also cleaned the oil control valves on both engines. 146k had the CEL/VSC light on and the other as maintaince. and to bring you up to date, 146k got new front rotors and pads, plus the new motor mounts.

good luck on yours Micah.

I assume you have all your work done for you 1990LS400, right?

[1990LS400]

hay you guys, This is what was causing the car not to be smooth at 80mph. I was having a slight movement in the steering and seats, not a shimmy or vibration, but something that should not be there. my other 99 was/is perfectly smooth, now they both are.

ALSO Micah, mine would come and go too..... at a steady 80mph, that eliminates wheel balance

I had also checked my tires, and just changed the poly-to OEM strut bushings.

the mileage on the one I just fixed is 146k, the other one has 161k, just done the starters on both, and a door actuator on 146k. I have also cleaned the oil control valves on both engines. 146k had the CEL/VSC light on and the other as maintaince. and to bring you up to date, 146k got new front rotors and pads, plus the new motor mounts.

good luck on yours Micah.

I assume you have all your work done for you 1990LS400, right?

I have the mechanical skills and most of the tools to do this kind of work (I've rebuilt engines, replaced engine/transmission mounts, completely dismantled cars, etc.) but now that I am in my 60's - a "child" compared to you! - and working long hours after being dragged out of retirement, I'd rather have my trusted mechanics do it. My time is worth more than I pay "Fred" or "Alan" and my only "garage floor time" these days is while doing oil changes.

I suspect the rate at which transmission and engine mounts deteriorate varies quite a bit -- maybe by climate and driving conditions. It's probably the same for the strut rod bushings which generally last between 40K and 80K miles before they get bad enough to cause vibrations at highway speeds. I don't know what symptoms your 99 LS exhibited when your strut rod bushings became worn but my LS had vibrations that came and went between 60 and 70 mile per hour depending on road crown amount and even wind conditions. I don't know what it would have been like at 80 mph since I adhere to speed limits and we don't have speed limits above 70 mph where I drive.

My 90 LS was still on its original engine and transmission mounts and vibration free at highway speed when I sold it in 2003 after driving it from new to 183,500 miles -- maybe your Texas heat causes them to deteriorate faster than up here in balmy eastern Kansas and the areas much further north where I drive. :)

[billydpowell]

I don't know what it would have been like at 80 mph since I adhere to speed limits and we don't have speed limits above 70 mph where I drive.

many of our roads are 70, but the police allow us 80 with out stopping us. they set their radar at 81, so we enjoy the extra, our roads are great(mostly).

I retired at 62, 14 years ago. Sold my auto repair shop "Richardson Automotive", after 30 years, just because I could.... several times I have wished I would have kept it.

Keep up the good work..

[Micah.Berry]

Hi there, 1990LS400:

You are correct about the mileage. I purchased it in April with close to 113k on the clock. I have just crested 122k miles and am making my Christmas list of fluids and parts to order based on my manual and gleaned knowledge from informative forum members, such as yourself and Billy. I have priced them from Sewell, and with the Club Lexus discount, most of it is fairly reasonably priced.

I recall your post about your lower strut rod bushings. I did some poking around underneath the car while I changed the oil, and didn't see anything torn; however, I realize that as rubber ages it becomes harder and subject to cracking. Such cracking may not be very visible. My car has several services at Lexus of Lansing, so it's got some very cold weather that it's lived through. Cold, age, and now hot - can't be very good for rubber longevity. I haven't located a machine shop to press out the old bearings and cram the new ones in. I do have one in mind though. I would like to avoid purchasing the entire control arms if possible. Long story short, I intend to replace those bushings too. The tranny mount first because of the ease of replacement.

I've learned that vibrations can come in two ways - through the seat/floorboard and through the steering column. I have both vibrations. The vibrations are usually quite small. When my family rides in the car, I'm the only one who is annoyed by them, and they are only an annoyance, nothing obtrusive. As noted, the vibrations come and go and don't seem to be dependent on each other. The steering wheel vibrates around 65 mph and the floorboard or seat doesn't. If I accelerate briskly from 65 to 80, stronger vibration comes through the floorboard. "Normal" acceleration doesn't have the stronger vibration. Strong acceleration from a stop is smooth up until higher speeds. Very strange... In both cases, the vibration will sometimes completely go away while speed is constant. My water bottle in the drink holder will have no waves in the fluid. Then, the vibration comes back (causing little waves in the water bottle). I mostly notice this while cruise control is on, and I'm traveling on the interstate through hilly areas. My hypothesis is that pressure from engine torque applied to the (possibly worn) transmission mount causes additional movement above the design threshold. I *think* the reason that I don't feel this at lower speeds, even with stronger acceleration is due to the drive shaft not spinning fast enough to overcome the damping aspects of the rubber mount. Just my thoughts... And I could be way off base.

Anyway, the transmission mount seems like such an easy replacement, and at $33 and change (from Sewell before shipping, but with applicable discounts) isn't expensive. I can change it while I change my oil. The strut rods appear to be a bit more involved, and I will do more research to understand whether it's the lower ball joints, strut rod bushings, or some other component. Also of interest are tires. As I've noted before, the dealership installed very cheap tires, but I'm inclined to wear them out before purchasing a set of Michelins. I had them balanced a few weeks ago by a local shop that did a good job balancing my Miata's wheels, which were also very difficult to balance properly. I haven't noticed any bubbles on the sidewalls; however, I don't understand what "dynamically" balanced means. My observations are that the mechanic places the wheel within a machine that spins the wheel at high speed. The machine tells the weight that's needed and where to put the weight. What is dynamically balanced?

Billy, thanks for your post and information.

I don't have near the mechanical aptitude of 1990LS400 or Billy. I'm 36 and sit behind a desk most of the day as an internal auditor for my company. Most of what I've learned, my Dad taught me or I've learned from forums like this or YouTube. I'm not afraid to tackle things automotive though. My last project was replacing the dash lights in my daughter's car. I simply need to have plenty of time to accomplish the task.

Thanks again, 1990LS400 for your insight and the time to post.

Micah

[1990LS400]

I doubt if I could explain dynamic balancing but you can find plenty of information by doing a Google. Spin balancing doesn't always mean dynamic balancing. For example, Costco spin balanced my aftermarket wheels and new snow tires in July but could not do a true dynamic balance due to the insufficient clearance between the brake calipers and rim and the lack of wheel lips that could accept hammer on weights. That type of balancing is usually just fine if the tires are good and the wheels are true.

It certainly isn't going to hurt to replace the transmission mount. It's only that Billy is the only person I remember who reported that a vibration like this was caused by that. There have been many people who have reported that they solved highway speed vibrations on 98-00 LS400s by replacing the strut bar/bushing assemblies.

Do you know anyone else with a 98-00 LS400? If you do and his/her car doesn't have a vibration problem, swap wheels and see if the vibration is the same. Have you rotated the tires to see if the vibration pattern changes? And, again, is your car still on the original strut rod assemblies at 122,000 miles? Some people have said that pressing in new strut rod bushings does not provides results as good as buying the entire assemblies but I don't have personal experience with replacing only the bushings.

[billydpowell]

[it certainly isn't going to hurt to replace the transmission mount. It's only that Billy is the only person I remember who reported that a vibration like this was caused by that. There have been many people who have reported that they solved highway speed vibrations on 98-00 LS400s by replacing the strut bar/bushing assemblies.

Jim, as I said, mine was not a vibration, just a "movement", hard to explain, I wanted it to be perfect like my other one is. and now it is.

I started with a vibration, but motor mounts took most away, then strut rod bushings helped, the poly was a disaster, but oem made it ride like a Lexus again, but the tranny made it "solid", perfect, no movement. seats or steering.

also, I have replaced the bushings both ways, with the whole arm and just the bushings. I got an extra set of arms from Landar, after he wrecked his, and put bushings in them, I have a press available to me,so it is not a problem, delay or expence for me to do bushings.

PS: I wish I had thought about the dealer price being so low on the mount, I just ordered a cheapie from the 'net. my boo boo.

[Micah.Berry]

Unfortunately, I'm the only one that I know *with a Lexus*. There are many ES, RX, and GX vehicles that I have seen in my area. I have seen a few 95 - 97 LS's, but very few 98 - 00 LS's. I'd love to drive another one, just to feel the difference. As an aside, every time I hop out of my daughter's Mazda, and back into the LS, I am dumbfounded at how smooth the Lexus is. Even with the vibrations, it's worlds nicer than the Mazda (which needs a little attention in its own right-thus my repairs budget is being spread over 3 cars and a motorcycle).

I will change the strut rod bushings, though I haven't determined if they will be next or third after motor mounts. I suspect I will do them next though. I continue to read and study videos on how to change them, and I may be making it more difficult than it truly is. Once I get to it, I'll probably be posting a new thread for your help! LOL! As a note, I did have the tires rotated / balanced several weeks ago. Vibration didn't change. Also, the car now pulls to the right. It used to track beautifully straight. I've verified that the pressures are correct, so the shop either knocked it out of alignment or (more probable) there's something worn that should be replaced. I'll have an alignment done after new bushings are pressed in. Just more to read about... But I do like the education I'm getting. I'm a firm believer in "no one takes better care of their stuff than the owner."

I'll read up on "dynamically balanced" versus a straight spin balance.

Thanks again for all the insight and help, and my apologies for the thread jack!

Micah