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Discussion Starter #1
I have an 88 Thunderbird 3.8L. When accelerating off the line it feels as if I am running over a small pipe on the road. That's the only way I can explain it. It's easy to duplicate and only happens when you stomp on it, at least half throttle off the line. I don't see anything wrong visually. I took the drive shaft loose the other day and the U-joints felt OK, one was a little stiffer than the other on the front end, but none were bad. I can only visually inspect the motor mounts, but they look OK and the engine does not rock in the engine bay when revved. I noticed the other day that a small amount of smoke from between the firewall and the engine will be visible on rare occasions. The engine does not leak or have any other problems. When driving normally everything seems to work well, no sounds, bumps or other signs of misbehaving.

Any ideas?
 

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I'd take out the axles and see if they have any damage.
 

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My uncles Spirit had the same symptom. With his one of the brakes was sticking, when you started slowly it would hesitate a bit but not to noticeably, when you gave it some gas off the line the brake would let go quickly and feel like a bump. Just a thought for ya.
 

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I'm not sure about the MN12s, but when my f-bodies (camaro & firebird) have had those symptoms, it has beem the tranny mount; worth a shot.
 

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hes not talking about an mn12. He's talking about an 88 tbird with a solid axle rear end. But yeah it could be a tranny mount. Just get under the car and start inspecting things. Try to move things around and see if they're lose or mounts are broken, and I'd take out your axle shafts and inspect those too.
-Thomas
 

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Thomas said:
hes not talking about an mn12. He's talking about an 88 tbird with a solid axle rear end. But yeah it could be a tranny mount. Just get under the car and start inspecting things. Try to move things around and see if they're lose or mounts are broken, and I'd take out your axle shafts and inspect those too.
-Thomas
My bad, I didn't notice it was an '88.
I used to be a member back in '00 or '01, when it was just MN12.
Alot has changed since. I like it.
 

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Discussion Starter #8
I am having a MagnaFlow put on tomorrow, I will check it out when it's up on the lift.
 

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Discussion Starter #9
We had it up on the lift and the motor mounts checked out OK. One thing I did notice is that you could move the output shaft up and down just a little. Not sure if it is suppose to do that. Transmission mount looked OK.
 

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i was always told that the diffs in fords tend to do that... and its true. Every RWD ford Ive driven does that eventually.
 

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Discussion Starter #11
Well it turns out that is was a broken motor mount. I tried a test mentioned in a forum to apply the brakes and then give the car a little gas while in drive. When I saw the engine lift up a couple of inches I new what the problem was.

 

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Ive seen that before. When I put in solid rubber mounts I removed my stock ones and they started dripping fluid and I thought "WTF" then I pulled it right apart... :leftright Get some solid rubbers.
-Thomas
 

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Discussion Starter #13
What do you recommend for the fox body as far as Motor mounts go? Do you have any links or part numbers? I put another stock one in for right now.
 

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Looks identical to the mn12's. But if you go to an autoparts store they sell solid rubbers. It may be a MOOG brand not sure, but there are solid rubebrs available at auto stores now.
-Thomas
 

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Discussion Starter #15
So they are a direct replacement and all the mounting hardware will fit or do you have to do some custom work to make them fit? What are the effects of solid rubber? more vibration, etc..
 

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More vibration felt through the car, Longer motor mount life.
 

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actually there's really any added vibration at all. I had solid rubbers for a few months and there was no difference in vibration at all. Now my solid mounts have a lot of vibration hehe.

The mount will last a lot longer, but the added bonus is that they transfer power to the ground more, since they dont compress as much when the engine torques at a launch like the fluid filled ones do, instead of power going to the mount it goes to the wheels.

-Thomas
 

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Discussion Starter #18
OK, sounds like solid is the way to go. Now for the other question. How do they go on? Are they designed to replace the original and will bolt right on using the stock mounting brackets or do you have to make something yourself?
 

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They're OEM style replacement so they'll bolt right in.
-Thomas
 
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