Clunk in reverse.

[Andrew C]

When backing out of a parking stall and I cut the wheel hard over I hear and feel a big clunk out of the drivetrain somewhere. U joint maybe? She's still got a bit of warranty on her so I'd like to have it addressed if it's an issue.

 

[krewat]

Might be the PTU or the RDU.

 

[jfalkingham]

2nd vote on PTU. This was the early symptom well before before my PTU was pieces on a highway

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[SHOdded]

Clunk in reverse will usually be the trans torque mount, or secondarily the solenoid body assembly. Can you localize where it comes from? The RDU and PTU tend to whine/grind more than clunk. The driveshaft COULD be at fault if the carrier bearings are shot, but the clunk would not be only in Reverse.

How many miles on your SHO? Kept up with fluid changes?

 

[Andrew C]

Clunk in reverse will usually be the trans torque mount, or secondarily the solenoid body assembly. Can you localize where it comes from? The RDU and PTU tend to whine/grind more than clunk. The driveshaft COULD be at fault if the carrier bearings are shot, but the clunk would not be only in Reverse.

How many miles on your SHO? Kept up with fluid changes?

Only around 48000 miles, and I haven't changed the oil in the ptu yet.

 

[krewat]

I had around 42 or 43K on my 2013 when I gave it back, and it was whining at 45-50MPH at cruise. But then, I drove that thing kinda hard

 

[xFallenxCripplex]

I have felt the same on my ptu I do have a very small leak where the rear drive shaft connects so if it is you may see the same

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[6500rpm]

Reverse only makes me think toque mount too, possibly CV joint. Does the wheel have to be turned to make it clunk? What does it do with the wheels straight, foot on the brake, and repeatedly shift between Rev and Drive? It's a warranty issue, really doesn't matter other than a learning experience.

 

[Andrew C]

Reverse only makes me think toque mount too, possibly CV joint. Does the wheel have to be turned to make it clunk? What does it do with the wheels straight, foot on the brake, and repeatedly shift between Rev and Drive? It's a warranty issue, really doesn't matter other than a learning experience.

If I keep the wheel straight it does nothing. Only make the noise when I cut the wheel hard over in reverse. So I'm thinking CV. Gonna take er to the dealership and see what they say.

 

[fordfanstan]

If I keep the wheel straight it does nothing. Only make the noise when I cut the wheel hard over in reverse. So I'm thinking CV. Gonna take er to the dealership and see what they say.

What was the culprit?

I started experiencing this a few days ago. 2015, 57k miles, maintained very well.
However, something seems to be binding, and then it doesn't want to reverse any farther, so I let off and don't proceed. I notice its more pronounced with wheels turned, but I think I felt it a a few days ago while reversing straight. I'm going to test it some more today and visually inspect.

PTU, Trans, RDU should be covered by 5y/60k mile warranty, but doubt CV's would?

 

[xFallenxCripplex]

Usually with trucks this is a sign that the ujoints are going so I'd check all the driveline connection points for any slop

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[fordfanstan]

Well over the last couple days I tried reversing numerous different ways in front of my house, straight, wheels clocked max, up my driveway incline (with/without wheels clocked) down the driveway incline, etc..I couldn’t get it to bind or stop in reverse again.

Jacked up the car and checked for bad wheel bearings, cv’s, u-joints, etc. Everything seemed tight and no leaks.

Fast forward on my way to work tonight, I pull into my work parking lot and couldn’t reverse into a stall at all, it would immediately bind and stop reversing after like 1’. Pull straight into another parking stall and shit it off and get out and immediately got the very strong propane smell. So must be PTU. I just serviced with Amsoil Fluids approximately 5k ago. Fluid that came out looked clean. However Im going to try to take to dealership and force the SSM 45053 And get it replaced ASAP since I’m at 4.5 years and 57.5k miles with no extended warranty.

 

[SHOdded]

Good luck, hope they treat ya right.

 

[xFallenxCripplex]

Well over the last couple days I tried reversing numerous different ways in front of my house, straight, wheels clocked max, up my driveway incline (with/without wheels clocked) down the driveway incline, etc..I couldn’t get it to bind or stop in reverse again.

Jacked up the car and checked for bad wheel bearings, cv’s, u-joints, etc. Everything seemed tight and no leaks.

Fast forward on my way to work tonight, I pull into my work parking lot and couldn’t reverse into a stall at all, it would immediately bind and stop reversing after like 1’. Pull straight into another parking stall and shit it off and get out and immediately got the very strong propane smell. So must be PTU. I just serviced with Amsoil Fluids approximately 5k ago. Fluid that came out looked clean. However Im going to try to take to dealership and force the SSM 45053 And get it replaced ASAP since I’m at 4.5 years and 57.5k miles with no extended warranty.

I'm thinking the rdu clutches maybe then

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[fordfanstan]

It didn’t happen again when I tried reversing from the stall in the morning. Drove 25 mins home, no propane smell. It’s completely intermittent. However from all the searching, everyone with propane smell it’s been the PTU that I can see in all the transverse models.

 

[gwrabbit]

I get a very light propane smell when I'm stopped at a light for 20-30 seconds, never when I'm driving or doing mediocre pulls. I also get a nice little dose of exhaust smell too, but that could be due to my catalytic converter that needs to get replaced. CEL came on this past summer and had my shop run the code and came back with a "P0420 catalyst system efficiency below threshold bank 2".

800$ parts and labor

 

[Johnbigdog]

I'm thinking the rdu clutches maybe then

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If the r.d.u. clutches where welded sold, he would have full time 4x4 and a shudder when turning drive or reverse.

 

[xFallenxCripplex]

If the r.d.u. clutches where welded sold, he would have full time 4x4 and a shudder when turning drive or reverse.

True well maybe something is broke getting cought in the pumpkin.
Oddly is smelling propane already though.

Now if you where able to raise both rear tires off the ground and turned the wheels what should we expect one wheel or bother wheels to spin. Or with the ptu always active are you not going to be able to spin it unless all four are off the ground?

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[Johnbigdog]

True well maybe something is broke getting cought in the pumpkin.
Oddly is smelling propane already though.

Now if you where able to raise both rear tires off the ground and turned the wheels what should we expect one wheel or bother wheels to spin. Or with the ptu always active are you not going to be able to spin it unless all four are off the ground?

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The rear diff is open.

If you raise the whole car up and spin the front or rear, there is enough drag in the A.T.C. clutch to rotate the other axle. My expirience the rear is not as good as spinning the front as the front is as good as spinning the rear.

If you just put the rear up and spin both, you probably will be able to once you defeat the A.T.C. clutch friction.

When I did my ptu flush, I put a screw driver in one of the fins of the r.f. rotor and spun the left front wheel to activate the ptu. This in turn does activate the rear wheels due to the friction in the A.T.C. clutch.

The ptu is splined to the front differential carrier, not to one of the side gears in the differential.

ATC = Active Torque Coupeling. It's the clutch that's in the front of the rear diff

 

[fordfanstan]

Ended up being PTU, replaced under SSM45035.