Manual Trans. Thud when shifting

daltron said:

My thud is now gone. I can only assume it was the driveshaft.

These are all my drivetrain related mods/fluids. The nice thing is that they were all done over time so I definitely think it was the driveshaft. What I bolded is what was the last install, with what I assume fixed it was the driveshaft. I have a PP with the stock 3.73 rear end with the Torsen.

Steeda Tri-Ax
DSS Aluminum Driveshaft
UPR Driveshaft Safety Loop
McLeod RXT
McLeod Steel Flywheel
DSS 1400HP Halfshafts
RP Synchromax
AMSOIL Severe Gear 75W-90
Steeda IRS Subframe Bushings
Steeda IRS Subframe Alignment kit
Steeda Differential Race Aluminum Bushings

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Out of the three bolded, I would think the driveshaft. Some people have talked about having some rotational play in their's which makes sense to me. Could be a combo of things, a tolerance stack up of several drivetrain parts.

Have a 3-week 2017 ecoboost that does this. Normally hear the thud when putting it into 1st gear.

I have a 15 GT PP with 5k on it and I have the thud. Thank god I don't have the vibration issue so many others have......

My thud is damn beer gone with Steeda engine mounts. You mileage may vary.

FordService said:

Let's get those Ponies running smooth, Tele5.0, MustangDirector, and Mangrove Mafia.

Checking in with your dealer is a great first step; let me know when you do so.

Also, as I'm seeing this is more than an isolated case, I want to document your product feedback. If interested, please send me your VINs and any additional details about the noise you are hearing while shifting.

Rachel

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It's definitely more than "more than an isolated case", it's ubiquitous.

Been through the dealer - they know all about it. Ford says 'nothing to fix' so their hands are tied. We finally agreed that they'd fix it under warranty when the weak link snapped. It's not news to the dealer so it's not news to the factory. At 9k miles it's still there but I guess I'm more used to it now.

In a Car & Driver 40,000 mile update article, they also experience the thud and state it is very objectionable.

The thud is from the two piece drive shaft. Went away when I put in a one piece in my GT. My 350 has the same two piece shaft and it has the thud.

skytop1 said:

In a Car & Driver 40,000 mile update article, they also experience the thud and state it is very objectionable.

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Well clearly those morons at C&D are just on the GM payroll and they also don't know what they're talking about.

Varekai said:

The thud is from the two piece drive shaft. Went away when I put in a one piece in my GT. My 350 has the same two piece shaft and it has the thud.

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I've read this before. Also read about people who changed to a one piece and still had the thud. Mine sound like the differential but the dealer mechanic is convinced it's in the tranny. Maybe it's different depending where the play is on a given car.

wildcatgoal said:

My thud is damn beer gone with Steeda engine mounts. You mileage may vary.

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Any problems go away with beer... ha

This is interesting, I was just looking at my stock mounts the other day and noticed they are very black ontop like fluid or burnt. Driver side about twice as much as the passenger.

Definitely not isolated case Ford Service. Mine is actually getting worse. Its on the back burner for other issues I need my dealer to look at. $33k car thats going to need every bit of that warranty I can forsee.

I believe the Thud is normal. My 17 GT does it. Has since day one. Currently 1800 miles on car. Very different Vehicle, but my 95 V6 manual trans Nissan Pickup does it as well. If only the MT82 felt as good as my 227k Nissan transmission.

Some say it's the 2 piece drive shaft. How can that be if it happens when the car is completely stopped?

I've tried to just learn to live with it. It just seems to me the driveline has so much slack in it. Like say in a parking lot in first gear even slightly getting on and off the gas there's a lot of clunks and driveline noise.

It is NOT the drive two piece drive shaft.
It is a combination of the rear end sub chassis and rear end shifting slightly against the main chassis. That is why the clunk thump is such a low frequency sounding noise.
While standing still, I can depress the clutch and rapidly shift between gears. Each time I enter another gear, THUD! Six gear shifts, six thuds. I am approaching 10,000 miles now I have never become used to it or accepting of it. The problem and aggravating noise persists. I read owners of the 2017 also have the thud and the GT350 cars have it too.

I am pretty sure I am moving away from Ford for my next car. I am very disappointment by the total lack of support from Ford with this problem and their lack of providing a fix for a production wide manual shift Mustang defect.

I agree. The driveline has been a total disappointment for me.