Hi Again,

After just having the car a few days, and being laid up with the flu, today I got tags, title, state inspection, and drove it about 50 miles. Like on the test drive, I notice a low frequency vibration that comes and goes, and sometimes, the steering wheel will shake a little. The car now has 67K miles, and is a 1995 vintage. I went to a tire shop and had all four tires rebalanced, which did nothing for the vibration. The tech said the the tires were balanced when he took them off the car, so then on the way home, vibration again, and with the tires ruled out, is the transmission mount the next thing to change, in the absence of something else obvious?

I am excited about the car, but the vibration kinda dampens the enthusiasm.

 

Tranny mount is the most likely thing. If you crawl under the car, you can probably contort around with a flashlight and see if the center section is partially or totally compressed. To what degree of compression is enough to cause vibration is anyone's best guess, though.

Other possibilities are fairly numerous. Steering rack bushings, upper or lower controls arms (front lowers most common issue), alignment, etc. Basically, any steering or suspension component.

BTW, what's your thought process that tires out of balance would be the cause of the vibration? That would be a repetitive thump, IMO, not an intermittent vibration.

 

Well, since I just got the car, I wanted to rule it out. The tires were flat spotted, but cleared up after a few miles of warming up. Other cars I have owned with a rear tire that has lost a balancing weight has produced similar vibrations, but you are right, it would be more all the time.

The steering is tight, with no play. Struts are still firm. This is the first SC400 I have driven. I also own a 1997 LS400 that my 87 year old mother drives, and with 136K miles, it has none of the vibration that I am noticing with this car. Neither my daughter nor her husband noticed the vibration, so I guess I am sensitive to these things. I once took a car back 3 times for a wheel balance problem. Turned out, there was something with the tires that caused a vibration. Another set of tires, everything was fine afterwards.

I can do a little maintenance, but with 3 fused vertebrae in my neck, I am limited as to what I can do on the car. I have the transmission mount ordered. Maybe my son in law will fix it, or I can get a local shop to change it out. Having a lift would be helpful.

 

The tranny mount is pretty easy to change with just jack stands, using the jack to support the tranny while "you" swap mounts.

The only complication I ran into was getting the cross member back on, as one of the bolt holes wasn't lining up. I finally discovered some metal slop left behind by the factory. (How it lined up originally was a bit of a mystery.) Once I had grinded that out smooth, the bolt went in easily. Someone else reported a similar problem as I recall. Just a FYI in case whoever is working on yours runs into the same problem.

 

Did you grind on the cross member or the subframe?

 

The cross member. The hole just needed to be cleaned out a bit so the bolt could pass straight through and line up properly with the threads.

 

Thanks for your reply. It doesn't seem many people are on this model forum. Are there any others that is more active?

 

I had a minor vibration that I lived with for about a year. Finally replaced the mount when it fell apart after loosening it to get to the oil pan. i should've replaced it earlier. Seems like it might be worthwhile given the age of your car.