I had my 1999 Bonneville SLE (normally aspirated) on the lift for exhaust work Saturday and the Tech. pointed out to me that my passenger side output shaft seal was bad and was leaking transmission fluid onto a motor mount located near the oil pan. I figured I would research getting a replacement mount because the rubber has been affected by the fluid and has become spongy. Trouble is, I cannot figure out what that mount is or where I can get one. Is it oem only? Nobody, including GM, seems to note that mount in any listing. Help!!

Question is, is he sure its coming from the trans output shaft seal? The oil pressure sensors have been known to leak and drip right onto the shaft making it look like its the trans seal leaking. Can you get any pics?

Is this the mount you are talking about??

Yes, it definitely is the shaft seal as the fluid is red. It could be the dogbone mount and I only saw half of it. I was kind of standing behind the oil pan so the mount only looked like half which is why I probably couldnt find it, as I wasn't noticing the whole mount.

Have a look at this pic:

Well, if it is the dogbone, then Autozone has them. Duralast/Torque Strut Mount-Engine part#2662. It'* special order. About $22.

They also have the output seal you need for the passenger side. Timkin 3543. About $10.

Are you planning on replacing the seal yourself?

More than likely its the dogbone mount. Its the only mount with bushings on the passenger side next to the output shaft.

Thanks for the info. Based on the pic, it definitely looks like it is the dogbone mount, I just didn't see the other half.

I'll probably have the work done; don't really have the time or expertise to pull the cv shaft or get at the mount. Working with ramps and jack stands......

Thanks again for the help. I'm that much further to resolution

No problem, please call again.

You're welcome, glad to be of help!

Thanks again for the replies. Always helpful. I looked for a "how to" post regarding the replacement of the mount, but couldn't find one in the forums. If it is out there, please point me in the right direction. If not, does anyone have details on how to replace the dogbone mount? Thanks again........