Drive Shaft Catistrophic Failure

[AutoBahn Terror]

Hello ALL,

Long time Lurker, First time Posting. So...Lets have some fun with this thread. Fairly well modded 2014 PP SHO, with more mods to come, Rolling down the German AutoBahn at 170 MPH, and then..BOOM!!! I thought it was a Blowout, turns out it was the Driveshaft, or as Ford calls it the "propeller shaft", from PTU to Rear Diff.

Still trying to figure out exactly what happened, and what the total amount of damage is, But it isnt as bad as it could have been. Drive Shaft Snapped in half, is the worst part so far, not sure if the PTU is damaged. My Corsa Exhaust took a Beating, so did the under body. My thinking is there are 3 possible reasons for failure:

1: Excessive Speed, 170 MPH is "Flying", to Quote Mike over at EcoPowerParts, and RPMs of the Drive shaft are approaching Ludicrous. If the Carrier Bearing in the "loop", failed, could have cause a drag on the shaft, creating imbalance which tore it in half.

2: PTU failure, This One is a maybe, but since me and Good friend Yanked out the Drive Shaft and Drove the car with out any issues in FWD only "mode", with no Grinding, crunching, or other noticeable hicups other than Excessive Torq steer, I am Fairly Confident its not the PTU, all though, until a new drive shaft is put in wont know for sure.

3: Wind! this one is also unlikely, but plausible. There is a heat Blanket that is located just above the location of the failure, at 170, I believe it possible that the blanket can be pulled into the shaft if a plastic grommet failed, pulled into the spinning shaft and this could cause failure if it got hung up, or cause a drag leading to imbalance...

4: Defect, which is the obvious one, especially when combined with the others listed. My mechanic buddy, says the carrier bearing is the most likely.

NOW, what does this mean for you guys? Probably not much, unless your in Germany with me and hitting the autobahn hard like I do. Unless of course You want the details of the Aftermarket drive shaft I plan on sourcing for your own cars... I am still in the VERY early stages of getting this sorted out, and I will Keep you all posted, More Pictures of destruction to follow after I edit the images for size.

Questions??? Comments???

 

[Linemonkey]

Wow. I'm glad nobody got hurt! A blowout would've been really bad. I guess, now we know how fast these things can go!

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[krewat]

Driveshafts are known to "balloon" at high RPM's although that might be a fallacy. In reality, it probably turns into an "S" shape and goes out of balance. It's one of the reasons the Mark VIII aluminum driveshaft was a good upgrade for the regular steel-tube Thunderbird/Cougar driveshaft if you wanted to go fast.

I once had my '96 T-bird with 3.73 rear up near 135MPH - all of a sudden, got a HORRENDOUS vibration and backed off. Weeks later, I took the car in to warranty something unrelated. Shop calls me and says the tail of the tranny is leaking and they need to order parts so it'll be a day or two before I can get it back.

The bushing in the tail shaft extension had galled and they had to replace the extension and the driveshaft. If course, it was because of the 135MPH with a lower-than-standard gearing (stock was 3.27). Difference is, I managed to back off of it quickly enough to keep it from coming out of the tranny. (The "S" shape makes the driveshaft shorter and pulls the driveshaft out of the tranny).

In your case, same idea. Looks like you're on your way to going to aluminum, or some kind of custom driveshaft

 

[AutoBahn Terror]

krewat,

since you have dealt wit tis before, in your opinion, should i delete the carrier support bearing or keep it.... i am still looking at what the racing community opinion and havent dove in to far yet on the matter...

 

[AutoBahn Terror]

more pics, some of the repair...

 

[krewat]

krewat,

since you have dealt wit tis before, in your opinion, should i delete the carrier support bearing or keep it.... i am still looking at what the racing community opinion and havent dove in to far yet on the matter...

I really have no idea - I'm not a part of the racing community, just a guy who likes to go fast. In my case with that T-bird, I would have just gotten a Mark VIII driveshaft and be done with it.

In your case, making absolutely sure that driveshaft is balanced at high RPM and making it stronger than stock I can't offer any more advice on the subject. But I will say, that hanger bearing is there for a reason.

Someone else with more experience with these cars has to chime in now ...

 

[AutoBahn Terror]

so far i have found that most mustang guys doing drive line swaps, upgrades, are deleting their carrier bearings. i phoned over to inland empire driveline, and they said they can build it no problem. the issues are i dont have any good measurements to do so. AND... i plan on doing a megan coilover swap soon, which 'could' change the geometry. im looking at doing somthing similar to this MP-06 Custom Aluminum Driveshafts 4" Aluminum shaft to replace the heavy stock two piece shaft. No adapter is required. $746.75 https://www.iedls.com. these guys do some serious work...

need to figure out the shaft rpm at 200mph in 6th gear, overdrive...

 

[SHOdded]

You need to go straight to carbon fiber, forget the aluminum, LOL! Maybe someone can look into the PCM/4x4Module tables to get the RPM at 200 mph?

 

[bpd1151]

I have been researching a vendor who makes custom carbon fiber drive shafts and plan on incorporating that into/along with a trans build.

Pricey, but they spec them to weight of car, power ratings, etc.

Interesting to see this thread pop up.

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[Lostneye]

Driveshafts are known to "balloon" at high RPM's although that might be a fallacy. In reality, it probably turns into an "S" shape and goes out of balance. It's one of the reasons the Mark VIII aluminum driveshaft was a good upgrade for the regular steel-tube Thunderbird/Cougar driveshaft if you wanted to go fast.

I once had my '96 T-bird with 3.73 rear up near 135MPH - all of a sudden, got a HORRENDOUS vibration and backed off. Weeks later, I took the car in to warranty something unrelated. Shop calls me and says the tail of the tranny is leaking and they need to order parts so it'll be a day or two before I can get it back.

The bushing in the tail shaft extension had galled and they had to replace the extension and the driveshaft. If course, it was because of the 135MPH with a lower-than-standard gearing (stock was 3.27). Difference is, I managed to back off of it quickly enough to keep it from coming out of the tranny. (The "S" shape makes the driveshaft shorter and pulls the driveshaft out of the tranny).

In your case, same idea. Looks like you're on your way to going to aluminum, or some kind of custom driveshaft

Hello from a fellow Long Islander. Funny thing is as a former Mark VIII guy myself and a buddy with much more power than I was making upgraded to aftermarket driveshafts. Then again my car had a big converter and 4.10s.

 

[AutoBahn Terror]

after some quick math with one vendor, 10000 rpm would be safe zone for me being on the autobahn for extended speed sessions, repeated runs up to and above 170 at intervals in excess of 2 mins.

 

[AutoBahn Terror]

where on the island, i grew up there myself, just saw krewat's location...

 

[SHOdded]

10 frickin' thousand RPM??? I would say that's screamin', but it is actually well past screamin'!!! That's speedbike territory!

 

[AutoBahn Terror]

SHOdded,

Please remember I am talking about Drive Shaft RPM, in 6th Gear, (OverDrive), with 3.16 Rear Diff as this is a PP Car...Failure was estimated by one of the shops I talked to, happened around 6500RPM shaft Speed, 5000-5200 or so Engine speed at 170...So 10000 would be a safety net

 

[SHOdded]

Ya, I know, I was just thinking pure RPM's Any idea of what your ET is to get to 170? Stock SHO acceleration starts slowing down after 60 mph or so.

 

[Lostneye]

where on the island, i grew up there myself, just saw krewat's location...

I grew up in Queens but was in ronkonkoma the last 10 years. I recently moved further east.

 

[AutoBahn Terror]

haha, thats funny, same here, except i didnt move that far east, went to lynbrook instead

 

[AutoBahn Terror]

Ya, I know, I was just thinking pure RPM's Any idea of what your ET is to get to 170? Stock SHO acceleration starts slowing down after 60 mph or so.

Well, NO...I have not tracked the car before. What I Can tell you is the last Dyno Run put the Car at around 430HP and Tq. which should give you a ball park estimated ET with a similarly modded car.

If I had to Guess, the car would be firmly in the 12.3s' if i did my part that is....

To get to 170, I cant recall as I am not starting at any particular speed, just whenever some Douche behind me flashes his brights at me, that's when the fun begins if I deem his car worthy of the fuel consumption...(its not uncommon for station wagons to be cruising down the autobahn at 120 Mph with little kids in the back seat flipping you off as they drive by...

 

[SHOinVa]

.(its not uncommon for station wagons to be cruising down the autobahn at 120 Mph with little kids in the back seat flipping you off as they drive by...

LMAO - That may be true and I could run a 100 myself all day and be comfortable BUT 170 is crazy fast, I don't care who you are. When I was much younger I might try to get her up there but the older you get the more you want want to stick around. I do have a question it takes a lot of energy to get going that fast as my understanding of aerodynamics the force multiply greatly over a 100, so how does she handle at that speed, mine actuality gets a little light a 110 or so and is there anything left of is she screaming. I never really thought of her as an real aerodynamic car.
- I went on a stock car ride along at Daytona once around 170 or so an the road got real small and everything happened real fast, it was amazing how much your perception changes.
C/

 

[AutoBahn Terror]

So, yeah, lets start with fuel. The usage is atrocious. If Im going at it hard, versus just cruising, Ill use an extra 1/4 tank or more over the course of the same trip; with a meth kit, anything over 125 and its on all the time, so a gallon and a half dont last long. Is there anything left? **** Yes there is, I fully believe that given the right time of day, (early sunday morning, no traffic on strait autobahn), I could Max out at 200 or more maybe, If the car didnt fly apart before hand. The Motor is that stout. Platform is the problem. I bought the car, not because I was a fan of the earlier SHO's or any other reason other than these 2: AWD with aggressive gearing, and the 3.5 twin Snailed EcoBoost. PERIOD. If I could find a way to have those things in a smaller lighter car, any car, without breaking the bank or getting a divorce due to a "love affair in the garage", Id do it.

As far as handling goes, once I wrap the needle, (140) thats when I really notice the "lightness" or "float" of the car, which is probably due to the height of the car and air getting underneath. I am still in stock PP suspension so some lowering would help me allot.

biggest problems at that speed besides death as a byproduct, are, brakes, the hood, (lots of air trapped under the hood), aero as previously discussed, tires speed ratings, and when they will decide to blow out, drive shafts, Hub Bearings and if they decide to fail at high speed, and of course a strong gust of wind which at high speed can cause you to "drift" into an adjacent lane. Not to mention, if all of a sudden someone sneaks in to your previously uncrowded road way and doesnt see you coming...

To be clear, I drive my SHO 700 or miles a week since bringing it to Germany last year, all highway miles. Usually I set the Cruise control at 95 mph and go; for both vehicle health and fuel usage. Sometimes thou, I just feel like Hanging my balls out the window and enjoying my car.

As far as age, I dont believe that whole heartedly, I know I am still young in my mid 30's but still i personally know some 60 and up folks who get the speed itch from time to time...