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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