Hi list!
To follow this thread with a twist:
I too have been having problems of 3rd gear but slightly different
systems. My tranny worked fine for 300 miles until I installed: the
Trany Tunnle, Center Support Dash,& carpet. Then it started popping out
of 3rd gear after I stopped accerlating [or when "crusing"]. Then after
the tranny runns for about 2 hr. It will intermitly pop out of 3rd gear
when in "cruse" mode.
Question: Is the infomation given to the other list member sill apply
to my problem, or is just "some" of the infomation given in the past
apply?
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Past info given: [see below]
Date: Thu, 22 Jun 2000 17:03:56 -0500
From: "Jack W. Drews" <vinttr4@geneseo.net>
Subject: Transmission woes
There are about a dozen things that can cause the popping out of third
gear, but 90% are due to two things:
1. Top hat bushing broken at the flange, or bushing endplay too great.
This can often be diagnosed by taking the top off the trans, moving the
gears so it is in third gear, grasping input shaft in one hand and
output in the other, and counter-rotating them. If you see the third
gear move axially on the mainshaft, the endplay is too great. (Actually,
this can all be done with the trans in the car, but you have to be a
contortionist).
The fix requires complete disassembly of the mainshaft, replacement of
bushings, and especially proper re-shimming, which means getting that
%&(*## square snapring off. I have resorted to treating it as a
throwaway item, destroying it to get it off, an putting a new $0.95 ring
on.
2. Detent springs in the transmission top, the ones that go into the
notches on the shifter shaft, are too weak. There is a factory spec for
this on the TR4 and on the TR6. I believe the spec is 32 lbs for the
TR6. Go to the hardware store, buy a $5 fish scale, and with the trans
top held upside down in a vise, see how many pounds force are required
to move the shaft off the detent.
I just went through the detent problem on my race car, with brand new
third gears and shifting collars in place ($$$$). After having the trans
in and out of the car three times, I measured pull-out force, found it
to be only 12 lb, I ordered new springs from Moss, put them in, and
found them to be just as weak as the old springs. Then I went through
all the trans tops I had, found the strongest spring, went to the
hardware store and bought a little spring that would just slip inside,
reassembled, and got about 28 lbs pull out force. Thanks to my fellow
racers who suggested this fix -- this was not an original idea.
BUT -- that solved the problem.
Good luck! -uncle jack
-----------------------------
Date: Thu, 22 Jun 2000 23:36:24 -0400
From: "James A. Ruffner" <erl@virginia.edu>
Subject: Re: Transmission woes
A transmission that does not want to stay in gear usually has one or two
problems.
1) The first is that the shift fork has gotten so worn that it will not
fully
push the selector fully over the gear dog teeth, and will not allow the
detente
ball to fully engage the recesses. Also, as someone mentioned, the
springs
behind the detente balls may be weak. Not a very common problem,
though. This
condition, if you read the manuals, is easy to detect before you ever
assemble
the trans. There is a very specific amount of force that is to be
applied to
each selector ring (gear) before it pops loose. If it is wrong, the
trans will
be either very hard to shift into gear, or will just slide in and out,
often
overriding the synchros, since insufficient pressure is applied to stop
the
gears from spinning.
2) The second is that the dog teeth on the gear, as well as the teeth in
the
associated selector ring have become worn, usually with a very slight
bevel.
This bevel is like a very, very small wedge in cross section. The result
is
that with the slightest pressure, the two mating bevels cause the gear
and
selector ring to simply push apart. This can generally be seen by
simply
pulling the top of the trans case off, and observing the dog teeth on
the gear,
in your case, third. This problem generally has its roots in someone's
driving
style, especially those who like to think they are at Sebring, and are
power-shifting everywhere. They snatch the trans out of gear without
the
clutch being fully disengaged.
To cure either/both problems requires the trans be pulled, and rebuilt.
Cheers, -James
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