One piece vs two piece drive shafts

[Jhol]

Hey everyone. I had an issue with my 2012 mustang gt pinion seal leaking, had the mechanic replace it and it leaked again. He said my two piece drive shaft was likely the problem. So I went ahead and ordered a ford performance one piece allum. Drive shaft. Got it installed with a front bmr bracket and another new pinion seal. No problems, but the car seems a little less spunky now. Like not as much jolt on a take off, or in shifts? If that makes sense. A little less fun to drive as a result. Lol.
I figured it would have better throttle response and free up torque but I can’t tell a change. If anything it feels like less torque. I was wondering if anyone had an idea as to why I may be feeling or experiencing this, and everyone’s opinion one 1 vs 2 piece drive shafts? The car is only pushing about 420 rwhp

 

[07 Boss]

It may be because there is no slop. Maybe that jolt you were feeling was the jerk as the slack in the two piece was taken up. I would think it would have been pretty bad to make a difference that your concerned about. But the whole thing sounds kinda weird to me from the beginning. How does a 2-piece make a difference in your pinion seal leaking? If the pinion angle is the same it shouldn’t know the difference. How bad was your driveshaft carrier bearing?

 

[Monkeyporn]

I too noticed the loss of SLOP when I went from a two piece to a one piece driveshaft. I thought it was a benefit to get rid of the jerk I haven't had a problem with my pinion see leaking. That said I do have a pop sound when I get down on it and hit third gear but I have no idea how to find it or fix it.

 

[Jhol]

Maybe that is what I’m experiencing (the lack of slop, resulting in no “jolt”). It feels more controlled and less exhilarating. It doesn’t help I haven’t driven it in like three weeks. (Due to a clogged fuel pressure sensor built into fuel line, wouldn’t allow me to put gas into tank.)
I can be a worry wart sometimes about my precious toy.

 

[WJBertrand]

Repeated seal failures would indicate the sealing surface on the pinion shaft has a defect (scratch, knick, groove etc.) or the pinion bearing is going out, allowing excess lateral pinion shaft movement that wears out the seal.

 

[Jhol]

The replaces seal didn’t look bad though, how would you assess bad pinion bearing? There would be backlash right? I don’t believe that’s the case. I’ll have to look at pinion flange

 

[Jhol]

Pinion flange didn’t have any noticeable damage either. I’m going to take a look at axle vent this weekend

 

[07 Boss]

That said I do have a pop sound when I get down on it and hit third gear but I have no idea how to find it or fix it.

UCA, stock or aftermarket? UCA bushing on the diff?

 

[Monkeyporn]

UCA, stock or aftermarket? UCA bushing on the diff?

I had the UCA replaced with a Doram one because the bushing were worn out. That said I did NOT replace the bushing on the diff housing because it looked in good condition. I still wondering if my pop could be the bolt being to small for hte diff busing and there being some slop there. When I drive it like a normal person would there NO pop however when I drive it like I stole it and hit thrid gear I hear the pop and its for sure coming from the rear diff area. I thought that maybe when I replaced the UCA that it might have changed my pinion angle but I haven't chacked that out. At this point I'm pretty lost on what this is I'm just trying to drive it gentle until I can solve this.

 

[07 Boss]

If the diff bushing is good I would be looking at the arm to chassis mount connection. Yes, most aftermarket arms will clunk because of the difference of the bolt hole size and the bolt. I believe Steeda used to make a set of stepped washers that would fix this.

 

[Monkeyporn]

If the diff bushing is good I would be looking at the arm to chassis mount connection. Yes, most aftermarket arms will clunk because of the difference of the bolt hole size and the bolt. I believe Steeda used to make a set of stepped washers that would fix this.

07 Boss thank you I'm going to go online right now and see if I can chase some down. Cheers Mate

 

[Olerodder]

If you have ever seen a video of the UCA bushing and the axle bushing I'm sure you would have replaced both. If one was bad the other was probably also, they're just rubber bushings and really should be replaced with Poly. I had my pinion seal replaced under warranty with less than 8,000 miles. The tech replaced it with a full metal one as the OE was a plastic material.

 

[Lime1Gt]

Hey everyone. I had an issue with my 2012 mustang gt pinion seal leaking, had the mechanic replace it and it leaked again. He said my two piece drive shaft was likely the problem.

I don't think so; either the mechanic did a poor repair, the output flange had scoring on it, which can sometimes be repaired with a speedi-sleeve, pinion bearing worn as mentioned post #5, or vent tube plugged. Fluid can also wick past the nut threads if the old nut was reused. I'm pretty sure the driveshaft would have to be severely unbalanced to cause a pinion seal problem.

 

[axis101]

While there, a consideration of lower engine mounts will aid in driveline alignment. A one piece install and lowered motor mounts, I could feel free up power and the fun element. Good luck.