The original U-joints are not replaceable. At least not without major machine shop equipment or expenses.
So there are three choices:
Theory
All 1 and 4 cylinder engines (except the ones with internal balance shafts) produce large torsional vibrations ( 2nd order harmonic ) which beat the cr.p out of the whole transmission line. These vibrations are not present in 6 and 8 cyl engines. One of the main reasons why the infamous guibo is used, is to isolate the crank from the road, ie driveshaft, diff and half-shafts, tires. On our engine dynos, the only driveshaft that lives for any length of time, is made for us by Driveline Services of Concorde, and consists of;
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This is a 4" tube over a 3.5" tube, with a rubber of shore hardness=60 sleeved between the two. This works fairly well on most engines, except for the big cosworths (2.4) which actually melts this rubber, with it's severe torsionals. What I'm saying here, is that a driveshaft on a 4-cyl engine is way more complicated than on a 6/8, and in the old days, the large aspect ratio tires provided some of the compliance, which the guibo provides today. As we move to low profile tires, it becomes more necessary to provide isolation in some manner. Every company in the world, that dynos 4 cylinder engines will tell you the same thing - you need compliance. There is a certain amount of inherent compliance in a car ie, springs in clutch plate, oil between gears in transmission, and rubber between rims and road, which is what allows us to run 1 piece shafts, but in all cases, the two piece, with it's giuibo will allow the whole driveline to live longer.
Rebuilt 2 piece
I got one for my wife's Scorpio last year but they also do XR4's and "usually have one on hand". There is a core charge - think it was$100.00 - and the core must be rebuildable. Think they shipped via UPS, took about 3 days to go from California to NJ.
They have a web site at http://www.driveshaft.com/ but it's just a single page with the following info listed:
Powertrain Industries, Inc.
150 Arovista Circle
Brea, CA 92821
Tel - 714-255-7030.
Fax - 714-255-7033
Toll Free 800-798-4585
Email - pti@worldnet.att.net
Rebuilt 1 piece
He says he has done great conversions on the XR driveshaft, welding the ends from your shaft on to new 3" diameter tubing and eliminating the infamous 'guibo', eliminating the center carrier bearing and installing 'off-the-shelf' greaseable Speicer U-joints. He says this conversion works great and that you pick up a few HP that is otherwise lost to the center bearing. Last summer, he told me he did this job for $200.
