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Park to reverse thunk, which mounts? (video)

J

jasonnovak

New member
Ok, so I seem to have the fairly common park into reverse thunk on my 99 GTP (207K). I'm hoping it's the top mounts since those are easy to fix, but I'm not sure. I did check the bottom mount through the driver's wheel and it looks good - no coated in leaking fluid at least. I can't tell if changing the dogbone would actually help - it does move around alot on the other end, I know some people rotate those to stiffen it up, not sure it's my preferred solution maybe it's the best one? Not sure how much movement is supposed to be there. Should I pull the bolt and check the other end?

https://www.youtube.com/watch?v=36GmB4mQxyE&feature=youtu.be
 


The lower motor mount has to be bad, judging by the amount of movement. You checked the drivers side lower mount, which is the trans mount and usually lasts longer. The passenger side motor mounts are known to fail after only about 120k miles. They also cause vibration. Check that one out, I can almost guarantee it's totally destroyed like this

s9bv.jpg


The amount of movement in the upper mount (in the video) is normal when the entire motor shifts in the engine bay, but I suggest flipping them since that's just as good as buying a new mount.

What a bad motor mount will look like. The motor is about 2 inches lower than it should be, and moves when shifting.
ojal.jpg


The new one is at the correct height and solved the clunk and the vibration issue.
pmcv.jpg
 
I was hoping that wouldn't be the issue, I checked the passenger side based on your pics and though a little different I believe this is it, guessing that's goop from the mount and not something else, though it looks like it's only half gone.

Any thoughts on doing something up top to make it a little better until I can do something in the spring?


 
You can flip the dogbone mounts and it may help a little, but it won't do much. The mount really needs to be replaced, it looks pretty wasted. That fluid may be from the mount. I bet if you had someone record that area from above the engine bay you would see the engine moving right at the mount.
 
time to change the motor mount and the tranny mount, very easy to change. flip the dog bone bushing too.

if you watch the engine when it shifts id bet its twisting a bit in the bay, watch the dog bones, they show the twist when it happens.

my old motor mount. same as above, shot to hell. see the bar that bolts to the engine, its slides, catches the other bar and makes that clunk sound and it lets the engine move some.

motormount2.jpg
 
I get the same park to reverse THUNK but only when the engine is cold. After its warmed up i can do it no problem with no thunking what so ever.... should i be changing the mounts too? i got about 228,000km on the car, owned it since 135,000km and im not sure if the mounts have ever been changed.
 


when the car is cold the idle is at 1000 rpm's or up to 1200. so its gonna hit a bit harder when cold.

pop the hood, watch your engine when shifting it in and out of gear. if its moving a lot the lower mounts are shot.
 
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