I have seen some people trying to put something together on the Cadillac Forum for a aftermarket style motor mount, but have not been there for a while to check it out to see if there is any new info. Some other info is that I have seen a 2006 Buick Lucern with a 4.6 installed and it had some quite interesting bracing from the front side of the motor, looks like a factory fix for the motor mount failure problem.

Northstar Performance has a solid mount for the Cadillacs. Not sure how it would work in a GXP.

Motor mount
 

According to GM Direct this is the part number for the 3.8.


The number for the N* is 25759455

I also checked AllData and it confirmed that 25759455 is the mount for the N*.

A good point Mike, and we have seen it alot in Auto stores and catalogs. They just dont seem to get we have a V8. Always good to cross reference online to check, and look at what your getting before you take a part home locally. It has gotten better since the beginning.

http://www.compnine.com/largeimg/9904216K00-004.gif

25759455 = Front Engine mount

25695932 = Transmission mount

25705786 = Trans/Engine rear mount

25710672 = Pass Side engine mount w/o absorber, channel, & bolt

25713699 = Pass Side engine mount W/ absorber, channel & bolt.




My question is, WHICH one is the one that normally goes bad?

Is there a way to visually inspect the mount itself?

I had the hood up and ran the engine up against the brake in fwd and reverse, and do have some movement, but without anything to compare it to, I don't know if it's TOO much movement or the normal/accepted amount.

It would seem like the front mount would be the one to take the most abuse as it's getting pulled apart each time you accelerate. The rear would only get compressed and should last longer......correct?

Any suggestions?

Thanks,
Ken

I don't know of one person here Ken thats actually replaced one themselves. (someone of the past might come in and refute that, never know) but of what I remember, all were done by the Dealer. The best description I remember of past threads, (our Forum search engine works) You are correct in that it is the front motor mount prone to fail, and the best description I have read is a definitive clunk when shifting between 1st and 2nd. As mentioned, there is a little play when reving in gear while stationary. If the mount is broke, that play would be very exagerated when this is done. Its a real PITA that not alot of our drivetrain can't be examined by ourselves without a lift. The car sit so low in the front My ramps only work with this car if I dig gravel out from behind the front wheel and place them there and back the car onto them. Still have a time seeing or doing more than pulling the oil plug and filter. :rolleyes: For me the GMPP has reminded me over and over of it's value.

After just putting the N* in my car the rear mount is a pain in the butt! there is three bolts on the trans mount and they are hard to get in. they are in a shape on a triangle. the top is easy and the bottom driver side is hard but possible and the right one is crazy cause it is behind the steering system. If you really want to know how to do it pm me and I can explain how to do it in detail. I will tell you this... out of the three bolts I could only get two of them on. I had to go to the dealer today to ask them about it and they said two is enough. I am going to have them put the third bolt in and it is gonna run me $46 bucks and I feel it is worth it. moral of the story is if you at least get the two in and have to take it and get the other one put in you are going to save alot of $$$$..

Took my 04 GXP in for an oil change yesterday and they pointed out to me that my front motor mount was broken as well. I have had some vibration in the front of my car for some time now and my Service Stability System light comes on everytime I drive now. A few questions, can this broken motor mount be the cause of my vibration and this Service Stability System light coming on? How hard is this to replace myself? Just FYI, the car has about 155k miles on it and both wheel bearings have been replaced. The front passenger side was def. bad so I changed it. The other one I just changed thinking it was causing the vibration and teh SSS light to come on. Made no difference and I'm thinking it was probably okay all along. Thanks in advance for your help.

My GXP's in the tranny shop right now getting a new tranny. I decided to but the front and rear mounts to replace while they had everything apart.

It's a good thing too. The front mount was in pieces (like I'd suspected, but had been unable to verify) when they took it apart.

Sorry, should have been BUY not but.(above).....