Tom Wood has this letter on file and available upon request. It clarifies his position on the H&T SYE setups.
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Thank you for considering me for your drive shaft needs. Through the years I
have experienced a little bit of a "bad rap" over my refusal to knowingly
build a drive shaft intended to run in conjunction with the Rubicon Express
slip yoke eliminator. Some people seem to think that I have some sort of
personal problem with the company or their people. That, I will assure you
is not the case. Personally I have the highest regard for them and almost
all of their products.
In addition to liability concerns, my rationales are for what I perceive to
be sound mechanical reasons. I will outline them for you here.
1. The method of cutting off, drilling and tapping the output shaft of the
transfer case while still in the vehicle, is something that I would neither
recommend nor attempt myself. I have seen many shafts ruined in this
endeavor.
2. After the shaft has been shortened, you will still have a substantial
area of unsupported shaft beyond the rear output bearing. This is not
entirely a result of Rubicon Express's design, but I would also consider
this to be a problem on a factory original shaft. The result of this is
known as "overhung load." The drive shaft which would install against the
modified shaft will weigh about 15 pounds while the factory original drive
shaft weighs about 9 pounds. This in itself will nearly double the overhung
load. We must also consider that under a load, the drive shaft will have a
tendency to want to straighten out. This will also increase the overhung
load.
3. You should also understand that in order for the new output flange to
install on the output shaft, there must be some minor internal clearance
between the splined bore of the flange and the splines on the shaft. Because
of this clearance, you will then have the potential for minor independent
movement between the flange and the shaft. This independent movement, over
time (sometimes a very short time) will wear down the splines on the output
shaft and enlarge the splines in the bore of the flange. When this happens,
it will, because of the looseness between the parts, allow the flange to run
eccentric. This will cause a vibration problem with the vehicle. Most
people, upon discovering this problem, will re-tighten the retaining bolt.
Unless the output shaft has been cut off perfectly square, this will cause
the face of the flange to be less than perfectly perpendicular to the
centerline of the output shaft. This will usually cause even a more severe
vibration problem. When people have a vibration problem and a drive shaft
that I have built, their problem becomes my problem. I see this problem as
avoidable and prefer to do so.
With any of the other conversion kits available, there will be a more
substantial shortening of the output shaft, reducing the overhung load.
Furthermore on any of the other conversions, the rear output flange or yoke
is solidly "sandwiched" between the retaining nut or washer and the rear
output bearing. This secure attachment will prevent the wearing of the
splines on the mating parts. Thus, preventing the problem as outlined above.
May I suggest you consider installing one of the other conversions available
for your vehicle? The initial cost differential, I believe to be modest. But
the mechanical quality differences are substantial. Ultimately you should
find the longevity, performance and strength gains to be well worth the
minimal cost and time spent up front. After all "doing the job right the
first time" is generally the most cost effective.
Tom Wood
Tom Wood's Custom Drive Shafts Inc.
Toll Free US 1-877-497-4238
Worldwide 801-737-0757
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