So an issue has popped up with my 06 GT over the past few weeks. Whenever I start my car (after sitting overnight or all day at work) and I put it in reverse, my car gets this odd periodic lurch or shake. It's better described as a muscle spasm - just a slight periodic shake or spasm. It even does it if I sit there with my foot on the brake and the car's not moving. It only does it when the engine is cold, and as soon as I put it in drive it stops. Any thoughts on what it could be?

 

FordTechMakuLoco is excellent, but there's many other videos regarding the 5R55S(/W/N) regarding all the issues you may have with the transmissions. In this case, it appears it's the valve body and/or a solenoid in the transmission. The servo bore is not likely the issue on this, that's a higher gear issue, but if one's goin' the others are not far behind.

It may or may not be that the transmission needs to be pulled. And it may or may not be that the price of fixing these issues on the current transmission is about the same as just getting a 'new' one. You'll have to explore those options. And as you can see in the videos it can be done by 'anyone' if desired, so if you wanna save the labor bucks and get the pieces and do it yourself... well, there ya go. I'd be game, honestly. I'm just sorta already messin' around with the timing chain situation on Awesome, and life keeps gettin' in the way... Soon(tm)... Oh, and I have a manual, so that precludes me from this job anyway.

I hope that helps, and I know it's not great news, but that appears to be the deal. Good luck, hope it works out ok.

 

Ugh, definitely not what I wanted to hear, but thanks for the info.

 

One question though, why is the issue only happening when I'm backup up and not when I'm driving and the car is shifting between gears?

 

Simplest explanation without getting into automagics inner workings: Whatever causes the 'reverse gears' to be applied is messed up, and only that in your case. It will not affect the other gears. It's *likely* the valve body, given what I can see, but it could be the solenoid(s) involved too.

Reverse is a 'trick' of the gears, two of them are engaged 'just so', and it happens to reverse one set of gears. The gears are all engaged with clutch packs (like a motorcycle's) and are nested dolls in there. Really quite magical, when you see it. Planetary gears here, sun gears there... locking this or that... it's not like a manual in many ways, and yet, it's exactly like one, just differently packaged and actuated. This automagic stuff... neat, but dang. If you wanna get a visual on the ideas... well, here.

It's so weird looking, but it works.

/Until it doesn't, of course.

 

Just a bit of an update - I realized yesterday that it's doing it while in park, before I ever move the shifter into reverse. It's less noticeable before shifting, but it's there.

 

And final update - it was a bad spark plug. The issue that I was feeling was a misfire. Never had a car misfire before so I had no idea what one felt like. Problem solved.

 

Great news glad it was something simple!

 

Haha! I love it when it's something oddly simple! Kinda weird that'd cause that but hey... if it's fixed, it's fixed and that's that!

So very glad to hear it wasn't the transmission.

Question: How'd you diagnose that to be the case? Just curious. Thanks!

/Aaand adding that to the memory banks...

 

I didn't diagnose it... took it to my mechanic. The spark plug he removed made a noise when you shook it, almost like something was broken inside? Any way, the issue is gone. He said the noise I was hearing was a misfire.

 

Geeze Houtex. Scaring the poor guy to death! haha just joking.

But you gave some good info cause I think my car might have this issue.. Well not exact. It makes a groaning noise when I put it in reverse. I just figured it was normal.

Glad the issue is resolved.

 

Hey, y'know, the way it was described...

It really sounded like it was that. Who knew it'd be a spark plug?