PontiacBonnevilleClub.com

There is a TSB about this exact problem published in 2008. It covers virtually all years, and they make a new clutch housing with revised bushing material to extend life and reduce fluid leaks. I don't have the article in front of me but a quick search will pull it up.

My preferred transmission shop called back this morning and quoted $1400-1800. They're familiar with this problem but have never seen a bonneville gxp. I'm gonna have it towed there because I trust them and they'll go through the whole thing and make sure it's solid. While everything is out I'm also gonna have any leaky hoses fixed and whatever else they might find. Probably a good time for them to fix the motor mount too.

Got my car back today! The shop had to do a full rebuild on the transmission including a new torque converter. While they had everything out I had them replace the spark plugs, front motor mount, and the alternator. It shifts smooth as silk now, which I actually don't like. I got accustomed to the jerking around as a result of the bad mount. That's gonna move a tune higher up the priority list. The damages came in at $2150. They had never actually seen a Bonneville GXP before, but they did a great job. Finding the N* in it thew a bunch of the techs for a loop, but they're very familiar with this setup (and problems) in Cadillacs.