FoD

I installed the GForce 2-piece Chromoly-Aluminum 1000HP Driveshaft replacement from Precision Shaft Technogies.

I also installed the Revshift Diff bushing while I was back there. Total install time took about 3 hours (for both), but actually took me all day due to Football and Hockey games being on...Halftimes and Period Intermissions were work-time for me.

My main center bearing in the stock DS was bad, and squealing something awful. I attribute this to, a.) shitty engineering to begin with, and b.) the installation of the Revshift MM and trans bushing, re-aligning the drivetrain, and causing the already bad DS bearing to finally give.

The new DS has the ability to be taken apart, and serviced if anything breaks down. Big plus! I also noticed the girth of this DS over the stock. The PST shaft is 3" on one piece, and 3.5" on the other. It has 2 billet connecting adapters on the ends. No more of that shitty rubber to shear, twist, and compress during heavy loads. It weighs approximately 12LBS more than the original shaft, and cost me the same as a OE replacement.

Weighing more is a downside to it, but after driving for about 50 miles this morning, at speeds ranging from 5 MPH to 105 MPH, I did not notice the increased weight. This could be due to proper alignment, and it not jumping during shifts like the old one was accustomed to doing. I have no vibrations at speed, and the only vibes I notice at all are between 5 and 10 MPH...feels like a sputter more than vibes too. Could be something else, other than the new DS...dunno.

Overall, pleased. I will be swapping clutches soon, so hopefully everything will be smooth as glass after that.

NIKDSC5

iTrader: (10)

Question...are you planning on keeping the factory diff? Also what was the cost of the drive shaft? I'm just curious as to compare it to DSS Carbon fiber drive shaft.

I know once the factory drive shafts go bad the are a pita. Need to find a shop that services subaru drive shafts.

FoD

I am keeping the factory diff until it explodes...had it replaced under warranty with a Gen 4...zero whine, and I flush/fill every 10,000 miles. The DS shipped cost me $900.

Forgot to mention, I have zero issues with aftermarket shifters. I know many have had issues with the 1-piece shafts (not sure about the Carbon shaft) being they are 3.5" to 4" in diameter. The 3" diameter seems perfect for an aftermarket shifter (PISNUOFF/07CTS-V).

NIKDSC5

iTrader: (10)

Gotcha. About 1/2 of what the carbon fiber costs. I'm impressed it was heavier!? Also did you do a before and after weight? Or just by feel?

FoD

Before and after. The GForce weighed 39.6 pounds. The OE weighed 28 pounds. They were weighed with me on a scale holding them...very technical.

shadyLS6

any pics of the main center bearing bracket?.. the DSS 2-piece ds i have center bracket is not optimal.. i get a low frequency vib at certain rpms in certain gears under load

NIKDSC5

iTrader: (10)

Also when you do upgrade the rear end it should be easy enough to remove the rear shaft, measure and have it modified to fit an 8.8 or whatever route you choose to go.

You should take some pics and post them up!

FuzzyLog1c

iTrader: (4)

You're not going to feel much in terms of rev speed with a heavier or lighter driveshaft because the moment of inertia is dominated by diameter. Iz=(1/2)MR^2. The biggest contributors are your flywheel, clutch, and harmonic balancer. The crank is interesting because it has nearly the same inertia as your driveshaft (roughly 4.00" in diameter and 60 lbs).

98cobra

iTrader: (32)

My creative steel driveshaft bracket keeps sagging. I going to rework it when I get the car back together.

FoD

Pics to come later today, or tomorrow. Gotta get it back in the air for pics.

shadyLS6

thanks.. no rush on the pics.. its is such a shame that these aftermarket driveline parts are all under the car and a never seen

the black sheet metal bracket that mounts to the main center bearing? man that thing was a pain in the *** to install b/c of those shitty bolts.. is it flush against the body or did you use a spacer like CS was suggesting on the cf thread?

FoD

Pics. I did not want to remove my exhaust again to get better pics.

Front (with Revshift Trans Insert):


Middle Bracket:


Rear (with Revshift Diff Bushing):

etcts-v

^^ Looks great, jealous..

01_SuperSlow

iTrader: (7)

Looks good! So is the drivetrain clunk gone?

McCall

Great review and thanks for sharing. I need to order the same thing to replace my stock unit that also has a bad center carrier bearing. So did you get from Gforce or PST directly? How long did it take to ship after you ordered it?

FoD

Clunk is gone. I still have a slight clunk feeling, but I'm pretty positive it is the stock flywheel. I will be replacing the clutch this weekend (pending bolts arriving!).

I ordered from GForce. I received the billet brackets/hardware from GForce within 2 days, and the DS took about 5 business days to arrive from PST. I had a small issue with the hardware not being complete, but noticed before I installed. Made a call to GForce, and they overnighted the correct hardware to me. Great Customer Service! If you're reading this, thanks again!

kl2onik

iTrader: (3)

Sorry to jump in on this thread, but I may be in need of one of these. I've had vibration at higher speeds and I'm running out of things to attribute it to. What exactly am I looking for on the driveshaft to tell me its taking a crap? Ive always done body work repairs but I have someone else take care of all the moving parts in my car.

Gforce Engineering

iTrader: (2)

Great feedback!
Thank you for posting this

Chris

Blackpanther99

iTrader: (8)

Looks real great. Any difference noticed while driving?

Qwkrhino

Is the clunk gone?