one piece DS

[GregO]

Obviously the 2 piece was put there for NVH.

I’m under the impression the 2 pc. is for safety in the event the car is impacted to the point of folding up. The one pc. has a greater chance of impaling someone. That chance being the motor and trans not dropping down and under and more likely up and into the cabin.
Just my take on 2 pc. vs. 1 pc.

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[WildHorse]

There’s really nothing to alter with either the rear cradle or diff. housing.

With the one piece DS it's put the angles beyond the 'safe' limits. Rear bushing support on the trans output shaft & accelerated wear on the pinion bearing resulting in not if but when those two will fail.

 

[Rapid Red]

Very interesting read..... one could always install the steeda tube frame K member, that lowers the motor . grin

Don't see a drive shaft impaling anyone is a crash. I'm more concerened about getting struck by lighting, then getting gut punched from my drive shaft.

 

[Red65]

Very interesting read..... one could always install the steeda tube frame K member, that lowers the motor . grin

Don't see a drive shaft impaling anyone is a crash. I'm more concerened about getting struck by lighting, then getting gut punched from my drive shaft.

If a wreck is bad enough to mess with the driveshaft., it will just twist/fold. they aren't that strong to forces that aren't torsional

 

[GregO]

With the one piece DS it's put the angles beyond the 'safe' limits.

Mine didn’t exceed the universally accepted 3 deg. maximum safe limit.
As mentioned the S550 is designed with a offset ( center right at Diff.)
Without trans spacers my DS angle was about 2 deg. ( this was all based off of a level surface and identifying the crankshaft axis angle front to rear along with pinion axis angle front to rear)
After .250” trans shim DS was within 1.5 deg.
Spicer U-joints require to be run at 1 to 3 deg. Never 0 deg.
45,000 miles later all is well with my daily driver.

 

[WildHorse]

Mine didn’t exceed the universally accepted 3 deg. maximum safe limit.

Really ? Always thought it was 2 degrees. I learned something new today, thanks.

 

[GregO]

@WildHorse , 24 pages of U joint knowledge, all good stuff.

https://www.waterousco.com/media/wysiwyg/pdfs/content/J3311-1-DSSP.pdf

 

[WildHorse]

24 pages of U joint knowledge

K I read all of it, and it still seems the front u-joint angle is gonna be a problem IMO.

 

[Robert3487]

This thread changed my next mod from QA1 Cf driveshaft to front and back Baer deep stage drag brakes. FWIW i've seen nothing but bad reviews on the DSS driveshafts even though it is much cheaper.

 

[WildHorse]

bad reviews on the DSS driveshafts

Look further. Their 800hp half shafts are junk. I broke my set. DSS refused to do anything. Stockers back on and zero issues.

 

[GregO]

K I read all of it, and it still seems the front u-joint angle is gonna be a problem IMO.

Yup,
Thats how I arrived at the .250” spacer under the trans crossmember even though KellTrac and Wildcatgoal figured this out about a year before I decided on the Shaftmasters 1 pc.

 

[DougS550]

Most don’t realize that the differential pinion yoke isn’t centered in the chassis. It is placed center right of trans output. I can’t remember the exact offset but .750” comes to mind.
I’ve racked my car on a certified alignment lift that’s leveled to near perfection and the only thing needed was to drop the trans crossmember .250” to .375” of an inch (about exactly what KellyTrac figured out long before I verified my car) This was all done with calibrated digital levels and some simple trigonometry.
With the factory Diff. offset the driveshaft is automatically set for proper U-joint angles.
I know Fulltilt is a great reference but Ford got this car right with the placement of the differential. There’s really nothing to alter with either the rear cradle or diff. housing.

For reference if anyone decides to install crossmember shims the factory bolts are to short for full thread engagement. The factory bolt measures long enough, it’s the lead threads that are to shallow for safe fastening when using .250 or greater shims.

Well, I'm not reinventing the wheel and doing my own detailed measurements. You guys seem to have done a very thorough job for my confidence.
** Would you say I would benefit from adding 1/4" shims on my 2019 Mustang GT PP1 "NOT-Lowered" OEM Magneride Shocks, by Adding the 1/4" shims on the rear transmission mount would gain a safety benefit for me?
Thank You for your help

 

[DougS550]

Look further. Their 800hp half shafts are junk. I broke my set. DSS refused to do anything. Stockers back on and zero issues.

I will probably install the GForce Outlaw or Ford Performance half shafts.

 

[GregO]

Well, I'm not reinventing the wheel and doing my own detailed measurements. You guys seem to have done a very thorough job for my confidence.
** Would you say I would benefit from adding 1/4" shims on my 2019 Mustang GT PP1 "NOT-Lowered" OEM Magneride Shocks, by Adding the 1/4" shims on the rear transmission mount would gain a safety benefit for me?
Thank You for your help

Being the S550 is an IRS design the lowering of vehicle ride height does not affect pinion angles.
If you decide on .250” cross member shimming Make sure to use a bit longer bolts. The factory bolts have a long tapered lead thread, not a standard square lead starter thread like typical fasteners.

 

[GregO]

I will probably install the GForce Outlaw or Ford Performance half shafts.

I have FP axle shafts (which are GT350 axle shafts) installed on my 2015.
Be aware, Ford upgraded the axle shafts on the 2018+ Gen3 cars to GT350 axle shafts on production models.
I’m almost 100% positive if your S550 is a 2018+ it comes standard equipped with the OEM upgraded shafts.
Hopefully another member can chime in and verify this to 100% certainty.

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