Hey guys, as some of you know I just bought a 1997 SC400 with 147K on it. I have a question, I have a whine from 25-30 on accelleration only (coasting it's not there, decel it's not there) that is speed dependant, not RPM dependant. I'm a bit worried about it, it's always there, always the same volume (warm or cold.) The car was very well maintained, the trans and rear-end fluid are great, had the trans fluid changed again for good measure last week when I had the power steering pump replaced (small seep). It shifts perfect, no other strange noises, and I was told by my mechanic that this is a planetary gear set trans and it's perfectly normal....Is this true? Any suggestions? Or should I worry at all? I'm going to have the Timing belt done again (it's not due till 180) but I inspected it and am just going to do it anyways for good measure, should I have them look deeper or is this just something that these cars do?

 

Def not normal.

 

That sounds bad, if this is something bad it's going back up for sale, I really don't want to drop 3K+ into this car after I just bought it.

 

Sounds more like a rear diff that ran low on gear oil or has never been changed causing this but hard to tell with not being able to drive it.

 

Videos
http://www.youtube.com/watch?v=KBepoFXF68I
http://www.youtube.com/watch?v=lhym9xUSyog

 

I would bet it's the drive shaft center support bearing. Mine started making noise this winter. Only does it around 30mph when it's real cold out. It's gone away now that it's warmed up outside.
This place has 'em for $150 (don't know if that's a good deal or not, first I found), but I bet it's no fun to change.
http://www.dealerdirectparts.com/199...18-sc400-2.htm

 

How did you pinpoint that? Did you have the dealer diagnose it? I'm thinking of taking it there to have it diagnosed.

 

Well as far as mine goes, it does it in any gear at the same speed so that eliminates engine and transmission. And it sounds like it's coming from the middle of the car. And I did some searches and apparently it's common on many different cars with center drive shaft carrier bearings. 30mph seems to be the magic number.
But definitely have it checked out by a professional. I'm just giving my best guess.

 

Gotcha..... It does sound about right though! I might find a little mike, stick it up by that carrier bearing, and see if that's the one. Thanks for the good place to start, I hope that's all it is, I can stand about $500 to fix this, if not, it's sell it, or drive it until it breaks something else.

 

Wow this is the same exact thing my car started doing after I swapped to my welded diff. I thought it was the gears in that but the drive shaft bearings would make a lot of sense since it was the first time my drive shaft had been really moved and jostled in years

 

Interesting.... I'm not going to worry about it at the moment unless it gets louder / changes range of speed. I've taken a DB reading of it, so I can track it logically. Has anyone had one of these replaced? I'm guessing about 5-6 bills for it to be done somewhere.