Pete,
The 5th gear from the stock box will work in the U/C box. If the "Good"
5th gear is the pressed together unsplined type it would be good to have it
welded. Don't let just anyone weld it because it takes some skill and the
correct rod material and it must be sized to avoid future failure.
The mainshaft of choice would be the one with the long thread and two nuts.
The shafts are interchangeable all other things being equal. There are
ways to fix the single nut setup to make it more reliable so that you don't
have to make a big teardown although it might be good to go thru the box
and replace the bearings and worn synchro's since it is a race box.
The torque for the mainshaft nut is 122 to 144 ft-lb according to the book
that I offered for sale the other day.
The end play for 5th gear should be in the .004" to .008" range and it is
controlled by the length of the sleeve and the length of the gear. It
should be measured with a dial indicator or thickness gauge after the
nut(s)is tight. Inspect the fat thrust washer to see that the sleeve has
not made a big groove because that could cause the gear end play to be
reduced.
Shift forks should be the same.
This may be enough info to get one into trouble but not enough to get you
out of trouble.
Stan (Not a guru)
================
At 08:04 AM 9/23/2003 -0400, Pete Dehmler wrote:
>I'm trying to fix one of those pesky "5th gear neutrals". I have an Ultra
>Close gearbox that started slipping at Mid-Ohio a few years ago. At that
>race, I stopped using 5th and then took the box out figuring to fix it in
>the future. The future is now. Here's what I have so far:
>I took the UC box apart (extension housing off, 5th/reverse gear cluster
>out). The thrust faces on the 5th gear assembly are pretty bad and the
>needle bearing assembly is also pretty well shot - one of the needle
>bearings has some up needles that apparently froze and galled, the race is
>scored, and the inside of the 5th gear assembly is also scored. I figure
>that the whole mess is pretty well beyond hope without some extraordinary
>effort.
>I also have a couple of stock boxes. I took the extension and 5th/reverse
>assembly off one of those - everything there appears to be in near perfect
>condition.
>Here's the problem:
> The nut on the main shaft on the UC box was only a single nut held with a
>locking washer that had one side bent up to lock the nut.
> There were 2 nuts on the stock box - a big one and a thinner jam nut. It
>took a major effort to break loose the jam nut, but eventually I got it free
>and after that the whole thing came apart easy. Problem is, I'm guessing
>that this rig (the one on the stock box) was set up to give some clearance
>to the 5th/reverse assembly. Unfortunately, I didn't have that thought until
>after I had gotten the nuts loose, and so didn't measure to see what was
>there.
>Question 1: Is the 5th/reverse assembly from the stock box interchangeable
>with the UC one. If it is, I would take all of the gears out of the stock
>box that are in the extension housing and put them into the UC box.
>Question 2: Assuming the answer above is yes, how do you set up the assembly
>on the main shaft ie - what is the clearance/end play if any, what are the
>torques for the big nut and the jam nut.
>Question 3: Do I need to change the shift forks also.
>Question 4: What have I missed?
>
>Thanks in advance oh great and wonderful gurus of the net, especially Stan,
>Gordan, Chris, Craig, and Mike.
>
>Pete Dehmler
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