Thump from rear end when shifting

[grantourer]

I have 250 miles on the car. I've noticed that when changing gears, just normally, between 1, 2, 3, 4 and even sometimes when sitting in neutral and putting it into 1st there is an "Thump" from the rear of the car. I don't feel it in the car, at all, but it is audible. Reminds me of my C5 when the automatic skip shift would kick in. Anyone have this?

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[Socalmustang]

I have a little under 450 miles and mine does the same thing. I only hear it sometimes, when I put it from neutral and then into 1st. From my understanding, I think it is normal.

 

[grantourer]

Hmm. Seems odd. There shouldn't be anything moving that much that the car would make a noise like that. And i don't feel it...

 

[EXP Jawa]

The thump occurs when you let the clutch out, or during the actual shift? There are seemingly a number of NVH issues in the car's powertrain/drivetrain. There are reported "thuds" coming from the transmission at gear engagement, as well as possible coast to drive backlash clunks. Its hard to tell which you're describing.

 

[mustangfamily03]

Take it in to be looked at. Let the service tech ride with you so they can hear it. Sounds like a problem. A thump from the rear when shifting is in no way normal and could be several things.

 

[113]

I think it's an MT-82 thing because I've heard the "thump" fairly often in the 6+ years I've owned by S197. Not all the time but often enough I've become used to it. Seems to happen most often when the engine hasn't warmed up yet and when the car needs an oil change.

 

[mustangfamily03]

Sounds like backlash, but we can't be sure where it's coming from. That's why I say take it to the dealer, let them fix it, report back for others.

 

[EXP Jawa]

It could be the transmission, but as I said above, I'm beginning to suspect that more than one driveline NVH issue may be present in these cars. We may have to start trying to sort out which is which and identifying individual symptoms. At the end of the day, though, he should have it looked at if sounds concerning to him. The tech might tell him that its "normal", but until you get them to give it a listen, you won't know. And that way, he's at least gotten the complaint on record in the event something does fail.

 

[grantourer]

Its when i actually move the shifter into the gate. Not related to the clutch at all.

 

[Barrel]

http://www.mustang6g.com/forums/showthread.php?t=11569

 

[EXP Jawa]

Then its got to be in the transmission or shift assembly. If it occurs when you are moving the shifter, presumably the clutch is already in and the driveline is a neutral-load condition. There really isn't anything going on that would cause a noise to come from the rear end. Thumps/clunks/thuds all occur during transitions, when something occurs to cause them. The only thing occurring that is relevant at that time is movement of the shift lever. But, as I posted elsewhere, drivelines are difficult to diagnose NVH issues on. Noises travel up and down shafts and emanate in other locations. It can sound like its coming from the rear simply because that's the path the noise is following into the cabin.

 

[grantourer]

Wow 19 pages. A lot of people have the issue.

 

[foghat]

Wow 19 pages. A lot of people have the issue.

General consensus is that, while annoying, it is not an 'issue' per se and is within the realm of normal operation for this tranny. That said, I'd love if there were a way to make it disappear.

 

[grantourer]

Only one I've seen actually "Fix" the issue was with a fluid replacement.

 

[foghat]

Only one I've seen actually "Fix" the issue was with a fluid replacement.

A number of people in that thread have replaced fluid and still have the thud. If only it were that easy.

Steeda trans bushing seems to reduce the thud, but at the expense of a lot more nvh in the cabin.

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