Ford-a-tude

I have been battling this wicked driveline issue for the last year. I am unsure exactly when it started, it's one of those things that crept up on me. Last Summer I did several "Upgrades" at once so I am not sure who the culprit is (other than me). Keep in mind I can prevent it by manipulating the throttle and clutch. I can eliminate it most of the time, but I am convinced that this is not normal under any circumstances. Please don't post "Driver Error" comments. I really need your help.

Previous mods:

Spec Stage 3+ Clutch
Spec Billet Steel Flywheel
New PIlot Bearing
New FORD OEM Slave Cylinder
Shaftmasters 1 Piece Aluminum Driveshaft

FMS 4.10 Rear End Gear
New Bearings
New Clutch Packs
OEM FORD Fluid w/ Friction Modifier

Prothane Motor Mounts
K-Member Brace with Torque Limiters (this was more for the stiff 1-2 shift)

Sometime after all this was completed I started noticing something wasn't right.
I have been researching this all winter and am pretty much at a loss.

I have tried several things in an attempt to resolve this.

New Trans Fluid, tried Motorcraft, Mobil1, currently using Pennzoil synchromesh
Checked all drive line bolts
Checked and adjusted pinion angle several times
Replaced Upper Differential Bushing with Prothane Unit
Replaced Transmission Mount with Competition Engineering Solid Mount
Pulled and Re-greased Pinion Slip Yoke

I have done all the work myself and researched everything to death before I started wrenching. I am sure it's my fault, but I just can't fix this one alone. I have only found one YouTube clip and it sounds EXACTLY the same as mine only this was on a BMW. Unfortunately there are no comments or any resolutions posted. I plan on spending the day in the garage tomorrow working on this so any ideas are truly welcome.

PNYXPRESS

Is there anything close that the DS could be hitting.

Either that or your rear gear isn't shimmed properly

Ford-a-tude

No the driveshaft is totally clear. I am trying to eliminate everything before I pop the diff cover off and look inside. I set the backlash to .008, shimmed the carrier and had good contact patterns and set the pinion preload to spec. I thought it could be the pinion nut came loose but when I greased the slip yoke I had the DS out and the pinion seemed solid.

BLACK-MACHINE

does it make to noise without the DS installed, this will help you to find out if it's clutch\transmission, or DS rear end issue.

Ford-a-tude

Looks like I'm dropping the driveshaft today. I have been thinking about putting the 2 pc back in so this will be a good test!

Kona_MCA

I have a 2012 V6 car with the Getrash MT82 that does the same thing. Feels like it lots of slack and slop in the driveline seems typical with all of the newer Mustangs I have driven. I guess my driving adjusted so I can drive it smoothly now with proper throttle and clutch manipulation but this is just about the most disappointing car I have ever owned. The more I live with the car the more I hate it. Ford got so many things wrong on these cars.

Ford-a-tude

Messed with the pinion angle again. I think I had is set wrong and I really hate trying to take measurements with this angle gauge. Anyway, it didn't reduce the jittering at all. I was thinking there was some binding going on from a bad angle. I ended up dropping the DS at the trans. So now I know that it does not do it without the drivetrain load. I still have a bad feeling that it is the springs in the clutch plate. I have seen numerous posts of Spec clutches where the springs get all loose. Unfortunetly no one posts a movie of what it did on the car. My thought here is that while the springs try to dampen the shock of clutch engagement, a weak or failing set would allow the drivetrain to bobble back and forth.

Ford-a-tude

Put the stock 2 piece DS back in and it's just as obnoxious as before. No change, so the Shaftmaster aluminum DS isn't the problem. That leaves the transmission or the rear end. I really wish I didn't have to pull one of these. I am still leaning toward the clutch being the issue but we'll see I guess.

Ford-a-tude

Pulled the rear tires off to lessen the load on the drivetrain and this has had the biggest effect so far. Not sure what it means. There is still a clunk as slack in the drive train is picked up, this is normal. The fact that the bobbling is gone or severly reduced has got me confused. I am also noticing that the rear rotors are pretty hard to turn by hand, at least harder than I imagined they would be. The brakes aren't dragging so it must be resistance in the rear end. Does anyone know if there is a spec in foot pounds to turn the rear axle?

Joecls

Does it make the same noise in reverse? Of it does then you can rule out the transmission. I'd say rear end pinion bearing I've heard that noise before and it was a pinion bearing not pressed on straight.