This installation was performed on a 2006 GT Hardtop Automatic by my friend and me there as photographer/2nd hand/technical support.
The Shaftmasters 3.5" driveshaft was selected over the 4" for several reasons; Increased clearance Rated higher for torsional yield 1350 series rear U-joint vs 1330 series Improved sound deadener to reduce harmonic vibration
This 2006 GT is lowered with a set of Steeda Ultralite springs, yielding a drop of approx. 7/8" in front and 1" out back. Dampeners are stock.
Shaftmasters currently offers this (and the 4") driveshaft with an adapter plate or a replacement pinion flange.
This thread installs the adapter plate. For those with the replacement pinion flange kit, see step 10 for further instructions.
This ‘How-To’ will cover the installation of the 3.5” Shaftmasters 1-piece aluminum driveshaft.
1. Jack the vehicle up as high and safe as possible. Always use jack stands!
2. Using a permanent marker (I used paper ‘white-out’), index mark the forward transmission output flange and the rear pinion flange (2 reasons, note the clocking of these 2 marks so the new aluminum driveshaft will be indexed as the OEM shaft, and incase you ever have to re-install the OEM shaft).
2A. If equipped, remove the driveshaft brace directly below the center carrier. It can be removed with the exhaust in place. This brace will not be used with the Shaftmasters.
3. With the transmission in neutral, e-brake off, rotate the driveshaft (or have a helper turn the rear tire) for best access to the rear CV bolts. Set e-brake (so the bolts can be removed).
4. Using a 10mm socket, remove the (6) CV joint bolts.
5. Using a 12mm (12 point) socket (or ratcheting wrench), remove the 4 driveshaft flange bolts from the transmission output flange.
Note: Release the e-brake and put in Neutral to rotate the driveshaft as necessary to gain access to the bolts. Do not forget to set the e-brake (may need to engage in Park for Auto tranmissions).
Note: Save these 4 bolts, they will be re-used.
6. Using a suitable pry tool (a flat blade screwdriver worked fine for me), insert it into the U-joint where it mates up against the transmission output flange. The driveshaft will compress slightly to allow the driveshaft flange to disconnect from the transmission flange. Use care not to damage or mar the transmission flange. If unable to wedge anything in, use a rubber mallet to break the contact between the U-Joint and flange (PB Blaster (or equiv.) may be necessary to loosen up any rust keeping it from separating).
7. Place a couple pieces a 2x4’s on top of the mid-pipes to keep the driveshaft from falling onto the pipes once the center bearing bracket is loosened.
8. Using a 13mm socket (and universal joint adapter if required), remove the 2 bolts from the center bearing bracket (located about mid-way on the driveshaft).
9. Driveshaft is now completely unbolted from the vehicle and now can be positioned to be removed through the rear in-between the mid-pipes.
A thorough cleaning must be done on the rear pinion flange prior to the installation of the adapter plate. The adapter is machined to an interference fit, so to have it mate against the pinion flange without any debris (Loctite, grease, etc.) in-between is critical!
Using a plastic scraper and/or single edge razor, carefully scrape off any dried thread locker off from the pinion flange.
Pinion flange should look as clean as this.
10A. Position the adapter plate into the pinion flange and using the 6 provided hex head bolts, evenly draw the adapter into the flange using a standard ‘star’ torque pattern until all 6 bolts are tight (but, not torqued).
Note: Do not put any Loctite on these bolts yet, must be installed dry at this time to avoid any Loctite from dripping in-between the adapter and pinion flange (Yes, it’s that critical!).
Note: To ensure the adapter is fully and evenly seated onto the pinion flange, rig up a magnetic dial indicator (or hold stationary anything non-metallic) and have a helper turn the tires to check for flatness/trueness on the face of the adapter.
10B. Once the adapter plate is fully seated, remove one bolt at a time and apply Loctite on the threads, re-install, and torque to 41 lb-ft.
Note: I used a piece of masking tape to mark each bolt that I Locktited and torqued to avoid any confusion.
BMR front safety loop Whether you need a safety loop is all up to you. Here’s NHRA’s take on it.. A driveshaft loop will be required on all cars running 13.99 or quicker and utilizing slicks, except vehicles equipped with street tires running 11.49 or slower.
For those installing a BMR front safety loop, see the installation steps below.
BMR1. Remove the 2 rear transmission crossmember bolts using an 18mm socket.
BMR2. Mount the BMR driveshaft loop mounting angle bracket to the transmission crossmember, re-install the factory bolts and torque to 55 lb-ft.
BMR3. Insert the new drive shaft though the BMR loop and let it hang until the 4 bolts on the driveshaft flange to the transmission output flange are installed and torqued complete. (no picture)
BMR4. See after step 11.
11. New driveshaft installation With the e-brake off, clock/index the white-out marks you made on the pinion flange and transmission output flange.
Position the new driveshaft up from the rear in-between the mid-pipes and carefully route up to the front (and through the BMR front loop, if applicable). Place rags over any sharp objects to avoid scratching the new aluminum driveshaft.
Mate up both ends of the driveshaft’s U-joints against the rear pinion adapter plate and the forward transmission output flange.
Rotate the driveshaft if necessary to pick up the previously used 4 bolt holes in the transmission output flange, and make sure the 6 o’clock markings didn’t move while rotating the driveshaft.
Once everything is in position, Loctite each bolt and snug down tight. Using an ‘X’ pattern, torque the bolts to the following; Driveshaft to transmission output flange: 76 lb-ft Driveshaft to pinion adapter plate: 41 lb-ft
Note: A standard socket – universal joint adapter – ratchet combo will not fit squarely on the U-joint bolts. Correctly torquing these bolts will be difficult without a 12 point Crow’s Foot. If you choose to use a Crow Foot extension, use the following formula to set your correct torque value.
(T x L) / (L + E) = Adjusted torque value (what you set on your torque wrench) T= target torque value L= length of torque wrench in inches (end of handle to center of socket) E= length of extension in inches (center of socket to center of bolt)
If using a 1” Crow’s Foot extension on the front U-joint bolts, here’s the way the formula works out. (76 x 12” torque wrench) / (12” torque wrench + 1” extension) = 70.15 lb-in torque.
BMR4. Mount the loop portion to the crossmember angle using the supplied bolts and nuts. (no picture)
BMR5. Position the loop so it’s even on both sides of the driveshaft (can use you fingers to check for even gap). (no picture)
BMR6. Tighten the 2 bolts and ensure the even gap is maintained.
INSTALLATION COMPLETE!
Baseline/comparison photos
Contact Robert at Shaftmasters directly for any additional questions and/or comments not covered in this post.
< Message edited by TacoBill -- 2/27/2008 9:32:47 AM >
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Current Status: Blown Motor MMR Street Mod 800 Shortblock Ordered.. yeah, it'll have FORGED internals
great write-up as always...So this wasn't on your car right? If I remember correctly you have the coast driveshaft right? Thanks again
Correct, this is my friend's GT. I have the 4" Coast, but if I had to do it over again, I would not hesitate going with this 3.5" Shaftmasters because of the benefits stated.
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Current Status: Blown Motor MMR Street Mod 800 Shortblock Ordered.. yeah, it'll have FORGED internals
Bill, thanks for another great write-up. I have the 3.5" tapering to 4" Spydershaft and have been warned about lowering my car. Since you have a 4" driveshaft I was wondering if you've ever had the shaft hit the floor pan when driving over bumps?
Posts: 868
Joined: 5/5/2007 From: Richmond, VA Status: offline
Bill awesome write-up as always, one question though. How did you guys change the pinion angle for the new driveshaft, as I understand it a 1-piece shift requires a 0° pinion angle or else whining or rear-end damage can occure. Did you adjust for that or do you see any issues?
Considering I live 20 minutes away from Shaftmasters I should buy from them! Thanks for the write up and do they do installs.....LOL J/K (I already checked the site). J
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2006 Mustang GT with Cervinis Kit Whipple H.O S/C 465 RWHP and 440RWTQ
Bill, thanks for another great write-up. I have the 3.5" tapering to 4" Spydershaft and have been warned about lowering my car. Since you have a 4" driveshaft I was wondering if you've ever had the shaft hit the floor pan when driving over bumps?
No problems (yet) in regards to the driveshaft coming in contact with the floor pan.
However, to be on the safe side, I have not (or will not) carried any adult passengers in the rear seat. Also, I have not modified my bumpstops in any way. I know a few guys out there have cut the top sections off their bumpstops to smooth out their ride, but this may backfire in regards to driveshaft clearances; just be aware.
Another important step is to relocate the passenger side e-brake cable support braket away from the senter of the tunnel. This applies to cars lowered more than 1" in the rear (but still a good idea for ANY lowered cars). (For reference, my Steeda Ultralite lowered the car approx 7/8" at the front, 1" out back.)
This is where and what the bracket looks like. The concern here is when the driveshaft travels upwards, it may come in contact with the head of the bolt. I haven't relocated my bracket yet, but will plan on doing so the next time I'm under my car. The whole process shouldn't take more than a few minutes.
Of course, going with a 3.5" driveshaft pretty much eliminates any and all clearance issues.
quote:
ORIGINAL: JRT1
Bill awesome write-up as always, one question though. How did you guys change the pinion angle for the new driveshaft, as I understand it a 1-piece shift requires a 0° pinion angle or else whining or rear-end damage can occure. Did you adjust for that or do you see any issues?
I do not have adjustable UCA or LCA's. With my Steeda drop, I measured my pinion angle at -2 degrees. My friend's car (in this write-up) is set up similiar to mine with the same Ultralite drop and he reports no vibration or gear whine (he has 4.10's installed too) at any speed.
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Current Status: Blown Motor MMR Street Mod 800 Shortblock Ordered.. yeah, it'll have FORGED internals
Considering I live 20 minutes away from Shaftmasters I should buy from them! Thanks for the write up and do they do installs.....LOL J/K (I already checked the site). J
Jason, you will like the Shaftmasters - and while they don't do the install, not too far from them is a shop experienced with the product, Ron's Tranz Man in Lincoln Park as well. I can get you the contact information if you need it.
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Auto, C&L, 89 tune by Lidio, 3.73's, Tlok, J&M LCA; LPW girdle/cover; SS Superstripe, Roush hood scoop. Dual GT500 take offs. Black bullitts. Shaftmaster aluminum drive shaft.
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Shaftmasters 3.5" Driveshaft Install (w/pics) - 
I'll be ordering it soon! Can't wait. 
on Us.
J
