1995 3000GT VR-4: PST 2-Piece Carbon Fiber Driveshaft (CFDS) Installation

• Why Do I Want To Do This?

  • Maintenance and Reliability:
    If any part of your OEM driveshaft goes bad, other than the rubber carriers or carrier bearings, there are no replacement parts available from Mitsubishi. Some examples of parts that are not individually replaceable are universal joints, löbro joints, and the transfer case yoke. A new shaft from Mitsubishi lists at $980 (January, 2004) and may develop the same problems in the future. The PST shaft completely replaces all the OEM hardware, except for the spacers for the carrier assembly (which are available from Mitsubishi). Further, the PST shaft uses replaceable universal joints, which, should they fail, can be replaced by any competent driveshaft shop for about $20 in parts and a little labor.
  • Performance:
    The OEM shaft weighs about 44lbs, including the carrier assemblies. The PST 2-piece shaft weighs 26lbs, and the 1-piece shaft weighs even less. Dropping 18 or more pounds of rotating weight off of your driveline has a significant performance benefit in reducing driveline loss and helping your car slow down faster when you brake.
  • Safety:
    Should you ever manage to break your carbon fiber driveshaft (not likely), the failure mode for carbon fiber is for it to splinter like a broom. This is much safer than a large steel shaft spinning at many thousand RPM, should catastrophic driveshaft failure occur.




• How Long Will It Take Me To Do This?

  • If you're not familiar with your driveline and you've never had it disconnected before, plan on about 2 hours so that you're not hurried.
  • Having done this swap a few times now, I'm down to about 45 minutes.




• Anything I Should Do Prior To Attempting This Procedure?

  • Make sure you've got a safe way to have ALL FOUR of your car's wheels off of the ground.
  • Don't forget to have a quart of tranny fluid around to refill your transfer case!




• What Mitsubishi Parts Will I Need?

  Technically, you don't need any OEM parts. However, if your car is getting on in years, you may want to replace some of the carrier hardware and/or the lockwashers on the differential flange.
  
  
  • (2) MB505283 Insulator, Propeller Shaft Ctr Bearing, Upr ($2.14 ea)
  • (2) MB505284 Insulator, Propeller Shaft Ctr Bearing, Lwr ($2.14 ea)
  • (2) MF445005 Nut, Propeller Shaft Self Locking, M10 ($1.26 ea)
  • (4) MF450406 Washer, Propeller Shaft Spring, M10 ($0.54 ea)




• What Other Parts Will I Need?

  • (1) qt. Transfer Case Fluid (e.g. Red Line MTL/MT-90 50/50 Mix)




• Where Can I Get the Stuff To Do This?

  	Part	Company/Contact	Part Number
  	Carbon Fiber Driveshaft	Arlene or Mark at Precision Shaft Technology (PST)	Critical Link Carbon Fiber Driveshaft
  	Transfer Case Fluid	Red Line Oils	Mix of MTL and MT-90 (50% each)






• Comparison of OEM and PST Driveshafts

      OEM (top) vs. PST (bottom)

  
  
  
  
  
  
  

• What Tools May/Will I Need?

  • 17mm Closed-End Wrench
  • 14mm Closed-End Wrench
  • 12mm Closed-End Wrench
  • 17mm 3/8" Drive Socket
  • 14mm 3/8" Drive Deep Socket
  • 12mm 3/8" Drive Socket
  • 3/8" Drive Ratchet Wrench
  • 3/8" Drive 6" Extension
  • 3/8" Drive Torque Wrench
  • 1qt. Empty Container
  • 4 Jackstands (or Lift)
  • 2 Extra Jack Stands (or something to support driveshaft)
  • 2-ton or Better Floor Jack




• Erik's Review

  • Let me start off by saying that "the jury's still out" on this one. I currently (May 13, 2004) no longer have a PST driveshaft on my car as I had some vibration issues with the redesigned one. PST is going to get me a replacement A.S.A.P., but in the mean time, I can't evaluate what I don't have. "Stuff" happens, and in my case, I get to be the recipient of the "stuff." Apparently most of PSTs 2-piece shafts have no vibration issues whatsoever, but mine did. Almost every company occasionally has a product with "issues" make it out the door. It's what the company does in response that makes the difference between a good company and a mediocre one. PST has have promised to make it right, including offering me a complete refund if that's what I wanted. At this point, I'd like to have a redesigned shaft that doesn't vibrate, so I'm willing to wait. I have no issues with PST, and at this point have no problems recommending them to others.
  • In the brief period I had the squeaking (but otherwise working) shaft on the car, I was very pleased with its performance. The car was more responsive, it felt like it pulled harder at higher speeds, and it seemed to slow down a little faster when braking. So far I like what I see, and I'm anxiously awaiting the new shaft... more when I have more info.
  • Update July 13th, 2004: Well, there's some good news and some bad news. The bad news is that I'm not going to have a CFDS anytime really soon, and I won't get to complete this review until then. The good news is that it's not PST's fault in any way, and I get my $1200 back. UPS lost my driveshaft. Yeah, the one Mark at PST personally balanced and shipped out to me. First, UPS "loses" half of my Tein HA Coilovers (May, 2001), and now they "lose" my CFDS. It's not like it's a small item that could fall into a crack somewhere...grrrr. But the silver lining is that now that I know my OEM driveshaft is ok (the vibration was due to the motor mounts) and that I don't need a CFDS now, I get my money back and can spend it on something else that is a more pressing need. If/when my OEM driveshaft gives me problems, I'll give PST a call and buy a CFDS, and hopefully UPS won't lose that one. So in summary, I still highly recommend PST as they have excellent customer service, they are responsive to their customers' needs, and they have great products. The reason I don't currently have a CFDS has nothing to do with PST and everything to do with UPS.

The Procedure

	Loosen Transfer Case Drain Plug
	Using your 17mm wrench or socket, loosen the drain plug.
	Completely Remove Drainplug
	After removing the drainplug, you should have a 1/3 to 2/3 of a quart drain out. Catch this oil in an empty container.
	Mark the Driveshaft
	Using a wax crayon, tire marker, or other marking tool, make mating marks along the entire driveshaft. Also extend the mark to the flange at the differential. Doing this allows you to reassemble and/or reinstall the driveshaft in exactly the same orientation as it was originally on the car. You may never need to do this, but it can't hurt.
	Unbolt Exhaust Hanger
	There is an exhaust hanger close to the front carrier assembly. You'll need to remove it in order to allow the driveshaft to be removed from the car. They are all 12mm bolts and there are 4 of them. If you're in a hurry, you can unbolt 3 of them and just let the hanger hang there.
	Support the Driveshaft
	Find some way to support the driveshaft, as you're going to unbolt it and it will drop down if not supported. I had some extra jack stands that worked great.
	Unbolt Front Carrier
	Using a 14mm socket (you'll need a deep one, as shown), unbolt the front carrier. Again, make sure you support the front section of the driveshaft now, as it will be hanging there somewhat unsupported.
	Unbolt Rear Carrier
	Unbolt the rear carrier just like you did the front one. For the nut on the driver's side, there are clearance "challenges," so you may need a universal joint for your socket wrench. I also found that a 14mm closed-end ratcheting wrench worked very well here. After unbolting the carrier, you'll need to support the center section of the driveshaft. I used another jack stand for this.
	Disconnect Rear Differential Flange
	The last connection on the driveshaft is the rear flange that mates to the rear differential flange. The bolt heads are 12mm and the nuts on the back side are 14mm. If you don't have enough leverage to break the nuts free, then you can attach a second, larger wrench to the 14mm wrench and pull on it. That's what I did. You can also brace the 12mm wrench against part of the differential support so you don't have to have a hand on that wrench. Finally, if you have trouble with the driveshaft moving as you try to break the nuts free, then you can either apply the e-brake or have a friend step on the brake pedal to keep everything still.
	Lower the Rear Section of the Driveshaft
	Be careful - it's a little awkward and weighs in the neighborhood of 20lbs. You'll need to push the shaft toward the front of the car about 1/4" to get the shaft to clear the differential flange. At this point, the rear of the shaft will be completely free. Move your support jack stands (or whatever you used to support the driveshaft) and lay the driveshaft flat on the ground as you move toward the front of the car. I found it easier to lay the driveshaft on a creeper so that I would have the heaviest (rear) section on wheels when I removed it from under the car.
	Disconnect Front of Driveshaft
	Removing the front of the driveshaft from the transfer case is really easy. Just pull gently toward the rear of the car and it will slide right out. Be careful when it is first disconnected, as there may be some residual oil in the splines of the driveshaft. After most of it has dripped out, you can stuff a paper towel or something similar into the yoke of the driveshaft to keep from dripping tranny fluid everywhere.
	Replace Transfer Case Drain Plug
	The transfer case should be basically empty at this point, so you can replace the drain plug. The tightening torque is 22 ft*lbs, so don't over-tighten it! If you think you may forget to refill the case, now would be a good time to remove the fill plug and put it somewhere to remind you to fill the transfer case before driving the car!
	Compare Old and New Driveshafts
	Just to double-check things, make sure that you compare both driveshafts. They should be the same length, and the carrier bearing on the new shaft should line up with the location of the front carrier bearing of the old shaft. Note that the 5-speed shaft is about 1" shorter than the shaft for the 6-speed cars, so if the new shaft is about an inch off from the old one, check your receipt to be sure you got the right one!
	Install Rubber Carrier
	If you bought a 2-piece driveshaft, then you'll need to install the rubber carrier onto the carrier bearing on the rear of the front section of the driveshaft. If you find it difficult to install, a bit of dish soap or WD-40 may help lubricate things to make it easier. Make sure you install the carrier in the correct orientation - there should be a piece of tape (and an arrow engraved into the metal flange) that indicates the direction of the front of the car. Note: Prior to shipping my shaft, PST was indicating that the arrow on the carrier pointed toward the front of the car. The message on the piece of tape (see pictures) also indicated this. That is incorrect. Unless the arrow on the carrier changes at some point, it should point toward the rear of the car. If you're confused, hold the carrier so that the flanges are parallel to the floor (flat) and the lip on these flanges curves downward. In this position, the side of the carrier that is higher (farther from the floor) goes on the driver's side of the car.
	Connect the Two Halves of the Driveshaft
	After installing the carrier on the front section of the shaft, it's time to connect the two halves of the shaft. Note that the carrier is installed backwards in this picture as the arrow is pointing toward the front of the car, and the passenger's side flange is clearly higher than the driver's side flange. Line up the mating marks on the two halves of the shaft (see red or yellow lines second picture). The halves should slide together pretty easily once you have aligned the splines. This bears mentioning a second time: Make sure that you align the mating marks on the two halves of the shaft; the shaft was balanced in this position, and you may get driveline vibration if you don't align the marks. The first and third pictures (cardboard background) above do not show the marks aligned correctly, but the close-up picture does.
	[optional] Assemble Carrier Spacers
	If you chose to replace the rubber parts of your spacers for the carrier assembly, now is the time to replace them. The upper spacer has a metal bushing that presses into it, so you'll need to reuse that part from your car. It should press out and back in with moderate force from your hands. A press is not necessary.
	Install Spacers Onto Carrier
	Install the spacers as they were on the OEM part.
	Lubricate Driveshaft Yoke
	This probably isn't necessary, but it can't hurt. Smear a little tranny fluid on the outside of the yoke on the driveshaft. This makes it very unlikely that the yoke will "catch" on the output seal of the transfer case and destroy the seal.
	Install Driveshaft
	After slipping end of the driveshaft yoke into the transfer case, support the driveshaft and align the carrier assembly with the studs on the car. Then support the rear of the driveshaft and attach the rear flange to the differential. Then bolt the carrier assembly onto the studs. Note that the bolts/nuts on the differential flange should be tightened to 36-43ft*lbs and the nuts on the carrier assembly should be tightened to 22 ft*lbs. Tighten the bolts on the differential flange in a cross-pattern like you would lug nuts. Make sure to reattach your exhaust hanger after everything is bolted in place. Note that the lower two pictures are shown with the rear section of the driveshaft removed so that the carrier assembly is more visible. These pictures are taken from the rear of the car, so you can see that the carrier flange on the driver's side needs to be higher than the one on the passenger's side. Obviously, the rear half of the driveshaft needs to be installed for the car to be driven :-)
	Refill Transfer Case
	Refill the transfer case with the appropriate amount of fluid. My 6-speed transfer case took about 1/2 of a quart until fluid began to fun out of the fill hole. For the 5-speed transfer case, the fluid should be filled until the level is just a few millimeters below the check plug hole.

Redesigned PST 2-Piece Shaft

	Side-by-Side Comparison
	The original design is on the top and the new design is on the bottom. For my particular shaft, the new one was about 1" longer than the old one, but there's plenty of room in the transfer case for it to be accommodated. Longer is ok (to a point). Shorter is bad. The lower two pictures show the update to the design: there is a 3/8" spacer inserted between the front half tubing and the carrier bearing. This was done so that the tubing (largest diameter) would not rub on the rubber of the carrier when installed on the car. Previously, the carrier bearing was so close to the front tubing, that the tubing would rub on the rubber surround of the carrier, causing squeaking noises and wearing away at the rubber.
	Clearance (Old Vs. New)
	The old design is shown above (red mating marks) and the new design is shown below (yellow mating marks). The close-up of the carrier shows the result of the interference between the tubing and the rubber: there is a "trough" of worn-away rubber from about 5 o'clock to 8 o'clock on the inner edge of the outer (raised) rubber surround. As for the new design, note the increased clearance between the tubing and the rubber. Now there's no way that the tubing can hit the rubber under any kind of normal driving conditions! With this fix, I get ZERO rubbing, squeaking, or other noises. Kudos to PST for updating their product in response to customer feedback!