[playdeau]

I have heard that the two piece driveshafts used in the S197 Mustangs will self destruct above 110 or 120 MPH. Is there any truth to this.

 

[wjbertrand]

Sounds like “legend” to me. The limited top speed (146 MPH?) of my ‘13 GT is higher than that. I’ve been to 130+ a couple times as well. So no, no truth to that.


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[JBert]

This is about the V6 driveshafts, not the V8 .... and yes there have been stories of them failing and "exploding" at high speeds. This was aound 2011-12 when the new V6 drivetrain was first released, and that is why the V6 speed limiter was set to something like 120 MPH from the factory, if I remember correctly. Pretty sure there are posts on here with more details.

 

[playdeau]

This is about the V6 driveshafts, not the V8 .... and yes there have been stories of them failing and "exploding" at high speeds. This was aound 2011-12 when the new V6 drivetrain was first released, and that is why the V6 speed limiter was set to something like 120 MPH from the factory, if I remember correctly. Pretty sure there are posts on here with more details.

Thanks, I have a 2014 V6 Automatic that I only occasionally take over 100 MPH. I tried searching the posts before creating mine, but couldn't find answers. Don't want to spend big bucks replacing the drive shaft if it isn't likely to blow up.

 

[JBert]

as long as you don't mess with the factory speed limiter, you should be fine ... plus I think they might have made some changes by 2014 model year

 

[Forddenial]

From firsthand experience there is a quite noticeable vibration/rumble/chatter....and that was only at 110mph

 

[Siber Express]

There are 2 or 3 that I have seen Videos of, one was at 135 MPH

I also know of one that did it on the Dyno Backing off the throttle

 

[kenv]

WoW! ^^ The car in that video only had 17,667 miles on it. That`s one of those "you pays your money & you takes your chances" moments.

Plus, I`d be willing to bet that was not the first time he did that with it.

 

[playdeau]

So if the GT driveshafts are made better, wouldn't an easy, inexpensive fix be to search junk yards for a 2011-14 GT driveshaft ? Is it the shaft that breaks or the u-joint bearings? Wouldn't the axle ratio matter, too? I mean a 4.10 turns almost twice(OK half again) as fast as a 2.73

 

[wjbertrand]

So my comments about this being legend are limited to the V8 GT.


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[JBert]

So if the GT driveshafts are made better, wouldn't an easy, inexpensive fix be to search junk yards for a 2011-14 GT driveshaft ? ...

that seems too obvious and easy, LOL ... not sure what is the difference that would make that not work

 

[Cimmerian]

I believe Steeda drive shafts are under $1000 and you could do the install yourself if you have the tools.

 

[Cobrajet67]

So if the GT driveshafts are made better, wouldn't an easy, inexpensive fix be to search junk yards for a 2011-14 GT driveshaft ? Is it the shaft that breaks or the u-joint bearings? Wouldn't the axle ratio matter, too? I mean a 4.10 turns almost twice(OK half again) as fast as a 2.73

There was no 4.10 in any modern Mustang after the early 1970s. I believe a v6 in 2011-14 only had either a 2.73 or 3.31 from the factory.
As I recall reading on here the pinion flange is completely different so you can't just easily bolt a GT driveshaft on a v6.

I believe Steeda drive shafts are under $1000 and you could do the install yourself if you have the tools.

A one piece driveshaft in an S197 has its shortcomings as well so there is no perfect choice.

 

[Cimmerian]

A one piece driveshaft in an S197 has its shortcomings as well so there is no perfect choice.

Care to elaborate? I don't mean that as challenging, just genuinely curious.

 

[JBert]

As I understand it: The center joint in the stock driveshaft is there to compensate for the driveline angle issues in this chassis. The ideal set-up is for the angles between the driveshaft and the transmission and the pinion to be equal and opposite, which cancels out the "phasing" issues as the driveshaft rotation changes slightly through the joints. But in the Mustang these angles don't work out correctly, so the joint in the middle breaks it up a bit and reduces the vibrations caused by the "out of phase" condition. (that is my rough layman's understanding)

So when you remove that center joint, the angles become more critical, and vibrations can be a problem. This can be corrected somewhat by adjusting the pinion angle, but that is not a perfect solution because the pinion angle changes when the suspension moves up and down, and also when the rear axle rotates a little under load or braking.

I have a one-piece aluminum driveshaft in my 2010 and it does have some vibration under some conditions, even after tweaking the pinion angle. It is not horrible and it is acceptable to me, because I have accepted a lot of NVH compromises as I made my car more road-track oriented; but for some people it would not be acceptable.

 

[crjackson]

Just to add a bit more to JBert’s synopsis. It’s not all about pinion angles. Apparently there’s inherent vibration in the driveline, regardless of driveshaft angles. The carrier bearing mount utilizes a rubber insulator around the bearing that allows these vibrations to be absorbed at that point. In other words, the bearing floats inside a vibration dampener. A one piece DS with CV a joint solves the angular issue, and the durability issue, but it doesn’t always eliminate the vibrations. There’s no dampening effect, since that’s removed with the carrier bearing, when the 1-Piece DS is installed.

Some people swear by 1-Piece CF shafts with a CV joint. The material itself seems to have some dampening effect, as well as allowing for a little torsional movement which has been reported to help. So far, my 2-Piece shaft has held up well at high speeds, but in hindsight, I feel lucky, rather than smart. I will be replacing my own DS in the near future with a 1-PC DSS and single CV-Joint unit, and hoping I don’t end up with an unacceptable level of NVH.

AFAIK - CF itself is a durability compromise also. It doesn’t handle impact damage very well. I’m guessing an impact from road debris or rocks, could be a very expensive lesson about it’s durability, but that’s just my personal concern.

 

[AlloyPony]

I will say, the driveshaft in my '13 GT appears to be the factory unit. It's got 98,500 miles on it. The center carrier isn't a rigid mount, I can actually grab the shaft and push it up and down in the rubber dampener mentioned above. BUT, the shaft is smooth as silk at any speed, even to 120 MPH.

 

[Forddenial]

IIRC there was something I read about being able to use the GT shaft in a v6 but you needed a 90's Cobra flange to mate with the diff...
I'm gonna dig a bit to see if I can find more/better info

 

[playdeau]

IIRC there was something I read about being able to use the GT shaft in a v6 but you needed a 90's Cobra flange to mate with the diff...
I'm gonna dig a bit to see if I can find more/better info

Yeah, please let me know if you find anything. I (dumbly) assume that since both use the solid 8.8 rearend with posi and the same(I think) 6 speed auto, they would bolt right up.

I believe Steeda drive shafts are under $1000 and you could do the install yourself if you have the tools.

I only paid $8000 for the whole car(01/2021) pre-Covid price craziness. sinking a grand into just the driveshaft feels like bad economics. I have put 1 piece aluminum shafts is my 1990 and 2001 Mustangs, but that was back when shafts were only a couple hundred dollars. Also, both those cars had shorter wheelbases so maybe the swaps weren't that NVH critical.

 

[Cimmerian]

I only paid $8000 for the whole car(01/2021) pre-Covid price craziness. sinking a grand into just the driveshaft feels like bad economics. I have put 1 piece aluminum shafts is my 1990 and 2001 Mustangs, but that was back when shafts were only a couple hundred dollars. Also, both those cars had shorter wheelbases so maybe the swaps weren't that NVH critical.

Mine was $7,000 (I also drive a 2014) a few months ago but I think I've already sunk about two grand in replacing the radio and whole front end and hood, not to mention new headlight assemblies. Unfortunately I seriously doubt we're going to see after market price reductions now, especially with Federal interest rates set to go up again in May.