Vibrations When Cold, But Not When Idling

[austinpower]

Hi I have a 1999 Lexus LS400, 122k miles.

I've noticed my car recently vibrates in the mornings when the car is cold. The vibrations are not present during idle. Once I get past 3rd gear, the vibrations go away. The car acts like it doesn't know when to shift gears. The vibrations in 1st and 2nd gear definately have a ocsillation rythm to them. Once the car is warm, the vibrations go away.

I just recently started to notice the same oscillations/vibrations when decelerating. They aren't as pronounced, but I can still feel and hear them.

I just pulled the codes, all codes are clear, no codes are present.

Any ideas?

[synikal1022]

Im curious to see what some of our experts say becuz im having the same issue......mine is a 1998 ls and i experience the slight vibration when its cold only.....no codes

[fblonk]

Hi,

Could be motor or transmission mounts. I have had to replace them on both my 98's when they hit 100k. It is very common. The motor mounts need to be done on a lift, but the trans mount is easily done in the drive. Motor mounts are around $100 each (2), the trans mount is around $45.

Changing the trans fluid may also help.

fblonk

[amcdonal86]

My first thought was tranny mounts. But I was too chicken to come out and say it.

If the rubber is shot, the cold probably exacerbates the issue and causes it to vibrate more. When the transmission warms up, so do the mounts, and then the rubber is more pliable and doesn't transfer so much vibration.

[austinpower]

Thanks everyone. I'll have it checked out.

[lexfourcam]

my car does the same thing if it tries to go over 2k rpm when its cold. i was thinkin it was possibly the mounts, and also noticed when im going about 70 the shifter shakes.

[dasha1]

my car does the same thing if it tries to go over 2k rpm when its cold. i was thinkin it was possibly the mounts, and also noticed when im going about 70 the shifter shakes.

I bought a 98 LS400 with 120K a couple of months ago and noticed that the ride did not seem as smooth and quiet as our 99 LS400. It also had a vibration upon start-up that lasted until I shifted into reverse. The Lexus dealer said the transmission mount was bad and quoted me around $350 parts and labor to replace it. The dealer also said that the engine mounts were fine. I declined the dealer's generous offer and bought the transmission mount on parts.com for around $40 and had a local mechanic install it for $50. The old one fell apart when he removed it.

Changing the tranny mount helped, but the 98 was still not as smooth and quiet as the 99. Upon acceleration, it sounded almost like an exhaust leak. The car also didn't seem as buttery smooth as the 99. So, I ordered the engine mounts from parts.com and had them installed a few days ago by the same mechanic. Wow! What a difference. When my wife first turned on the ignition, she couldn't tell if the car turned over because the former noise and vibration associated with the car cranking were gone. The noise that sounded like an exhaust leak was gone also. The ride in the 98 became as smooth and as quiet as the 99. Having good engine and transmission mounts is really key to obtaining the smooth ride these cars are supposed to have.

Interestingly, I looked at the old mounts after they came out and they were not torn at all. They were compressed by at least 1/2 inch, according to the mechanic. The compression of the rubber was apparently enough to reduce their ability to absorb the vibrations.

It seems that one test for whether your engine mounts are absorbing vibrations like they're supposed to is turning on the ignition. You should feel almost nothing. If you can feel shakes/vibrations, your engine mounts are likely compromised.