Has anyone had experience w/ replacing motor mounts on 07-08 4.0L resulting in improved shift feel? Less herky-jerky-ness under acceleration?

We recently purchased an 07 Limited 4.0 FWD w/ 50k. The shift quality is quite rough, which I now know is not uncommon. I know there is a TSB for improving shift quality, but we spoke with one dealership who said they could not work on it if there where no SES warnings/codes present. I think that's a ridiculous statement and I will talk with some other dealers to try to get the TSB performed. In the meantime, however, it feels like some of the rough shift feel is partially due to too much physical movement of the engine & transmission under acceleration. I know the motor mounts have been a constant issue with these vehicles. We never had a problem w/ out '06 3.5L, but the 4.0L is much torquier. While brake-torquing in Drive, the front of the engine twists/raises up a considerable amount. Probably at least a couple of inches of upward/rearward translation. I went ahead and ordered front & rear motor mounts, Anchor brand, from RockAuto. I will report back after I've installed them.

Any similar experiences? Tips? Suggestions??

Thanks,
Matt

 

Well, I replaced the front mount Monday night, and WOW what a difference. That was clearly the problem. The acceleration and shifting is much smoother and quieter. No more clunking & jerkiness, and a less harsh engine noise under acceleration. These mounts are fluid filled hydraulic. The new Anchor mount (part number 3147), I could hear the fluid sloshing around when I shook it. The old mount, not at all. The lower stem/stud was seperated from the outer rubber shell, and all the fluid had apparrantly leaked out. It was simply allowing the engine to move until it hit the hard stop within the mount. I was not able to change the rear mount, as I was unable to jack the engine high enough to get the old one out. I was running into clearance issues to the firewall & radiator to get it any higher, and I was not willing to do any further disassembly. The front mount seemed to be the main culprit anyway. Hope this info can help someone else out in the future. If anyone's interested, I can go into more detail of the replacement procedure.

 

Hey Matt!

Brand new to this forum with this being my first post. We've also got a 2007 Pacifica 4.0 Touring with a collapsed front motor mount (just diagnosed last week). I would be VERY interested in knowing the exact procedure you used to replace the front mount. I just recently changed the mounts in my 1991 Mercedes 300E which were a piece of cake. Hopefully the Pacifica will be just as easy.

I also have the ESP-BAS and traction control lights on on the dash. The code says the steering angle sensor is the culprit. Any clues as to what I can do? Where is the sensor?

Thanks in Advance
Nick

 

Nick,
It was all fairly straightforward. First, I disconnected the battery. I then jacked up the front of the vehicle high enough to be able to crawl around underneath, and supported it with jackstands. Getting access to the top nut on the front mount required a ½” drive universal joint (which I had to go buy) to get a socket on it. You’ll need a 21mm socket for the top nut, and I think it was an 18mm for the bottom nut. I used an impact to break them loose. Remove both the top and bottom nuts. You’ll also need to unbolt the rear lower mount and the passenger side “horseshoe” mount to allow you to raise the engine high enough to get the front mount out. The unbolt the rear mount, just remove the bottom nut where it bolts to the rear crossmember. The passenger side mount is underneath the air box, so you need to remove that to get to it. Once the air box is out of the way, just remove the two bolts where the mount is bolted to the frame rail. I actually used two jacks to jack up the engine/trans (w/ blocks of wood on top of jacks to prevent damage to engine/trans). I had one under where the engine & trans is mated (driver’s side), and the other under the oil pan (passenger side). The oil pan is cast aluminum, so it’s pretty stout. Using two jacks allowed me to tip the engine/trans as needed while raising it. Be careful when raising the engine so you don’t pinch or damage any wires, hoses, pipes, etc. Go easy and don’t force anything. My first obstacle was the side cover on the driver’s side of the transmission which was hanging up on the lower edge of the frame rail. It took some persuasion to shift the engine/trans toward the passenger side to clear the frame rail (gentle prybar action). At that point it starts to get pretty tight between the accessory drive belt/pulleys and the passenger side frame rail. It took me awhile to get it high enough to get the front mount maneuvered out of there. When putting in the new mount, be sure you have it oriented the right way (there’s an alignment pin on the top of the mount) before tightening the top nut. Slowly lower the engine/trans and be sure nothing gets caught or pinched. Reattach all the mounts, air box etc., etc. That’s pretty much it. Hope this helps. Good luck and be safe. Let me know if you have any more specific questions.

 

Thanks Matt

 

That's hilarious.

There's actually no way to do it and be 100% sure you're not going to damage anything except to unbolt/remove a bunch of stuff from the engine and lift it up 4 inches.

What just about every one does is jack the engine up as much as you think you can get away with without damaging anything and drop the engine cradle much as you think you can get away with without damaging anything and hope you have enough clearance.
Actually, it's even worse than it sounds.

Buy a decent car is really the best advice any one can give.
Cheap cars should be easy to work on.
This thing/job is a disaster or abortion, as my Catholic friends would say.
It's filled with useless options when that money needed to be put elsewhere.
It's a half car, half minivan, half SUV, half wagon, cheap luxury car, that's hard to repair.
Reminds of that movie "Pentagon Wars".
Like the Bradley Fighting Vehicle it's designed to do nothing.
I don't see any one who knows anything about four-wheeled vehicles ever wanting this thing.
This was designed for soccer moms, that don't know any better and didn't want a minivan because they're supposedly lame, I guess because they are designed with a purpose in mind.
Then they complain on internet forums that it almost killed their miraculous bundles of joy.
Maybe I was wrong; maybe that's its primary function!
To kill idiots that glue a Jesus fish on the back of their ****boxes. It's called natural selection.

 

Does anyone know if solid mounts are available. The oil filled are junk.
Also what type of fluid is in them? I have the '07 AWD 4.0l

 

rock auto Westar "S" model (S for Solid) -- I got two and both were oil filled
One was 3 ounces heavier than the other
The light one clearly had more air

Go to main auction site and find the one that has 5 or 10 year warranty
That one I'm pretty sure is solid
It is 1 lb heavier than oil filled DEA mount
The DEA seems to have little air in it
On 3.5l V-6 I put the solid one in the front and DEA oil filled in the rear
It sends a little more vibration through the car, which doesn't bother me

 

I replaced mine but I went to Mercedes dealer to get them. The parts store brand are inferior to OE. I also did it in my driveway not to big of a job. Just remember to support the engine with a jack.

 

Front, rear, transmission mount and right front mount all had to be replaced at 24,000. Month later bolt found hanging down from sub frame to body under passenger seat and hitting ground. They tightened and checked all other mount bolts.
9,000 miles later driver's side motor mount bolt to frame missing and feels like other mounts loose or broken.
Have lifetime wrap however they say motor mounts are ware item. I am going to battle with managements as paying this much for a new car, one should expect motor mounts actually should last more than 24,000, and again problem in 9,000 miles.
Is it possible front drivers bolt to frame was loose and stripped where it bolts to frame. Car is being driven by mother-in law now 90 years old and light footed on gas. This is not an issue on hard acceleration.
Have appointment to take to dealer this Thursday to fix. I want to be able to tell them may be issue with actual frame threads (?) if applicable. I don't know why else a bolt would be missing after 9,000 miles.
Strongly recommend anyone with 2007 check all mount bolts or have dealer ck torque to make sure all tight. If one loosens up, can damage the rest of them.