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gear shift stick movement in 3rd gear question

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TOC said:
If the .086" is down between the shims and third gear, too much. The only other thing I can think of to look for is tapered (worn) engagement dogs on third gear. These are the second set of "teeth" that the synchro ring actually engage. On other marques, see high-mileage tansmissions where those are worn on one (or maybe both) sides to a taper pointing towards the synchro.
Get a good light and maybe a magnifying glass, and look at them, comparing shape to 4th, second and first teeth.
Just in case.
Click to expand...

.086" is the gap between the rear face of the 3rd speed gear and the front face of the 2nd speed gear. See attached image of what I am talking about. You will notice that 2nd speed gear has an undercut in which the shim is inset into it.

I took a look at the dogs and don't see any issue, all look the same. This transmission was rebuilt by a local shop about 5000 miles ago or so.
 

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You should be able to measure the gap (.086") and prise 2nd and 3rd apart, re=measure, and hopefully about .090"
 
If it'll help any, a few years back when I lost 2nd gear, I documented the teardown and rebuild of my 1500 on this thread. Lots of pics and fairly comprehensive; it might make a handy reference for you to see what's where in your tranny box without taking it all apart. :thumbsup:
 
I have been doing some research. Looks like the main line shimming is from first to third....I think.
Since there isn't a collar on the mainshaft between second and third, and second gear doesn't move, the synchro hub is supposed to move a bit (contained by the circlip at the front and third gear on the back), the movement does not occur at second, which loose shimming theoretically would show, then we're back to the synchro assembly.
Tapered dogs, or tapered grooves inside the ring (which is going to be difficult to discern in place), or too much movement of the synchro hub.

At this point, if it ain't jumping out of gear or howling, run it as is.

Dave
 
Okay, I was on the right track. Found a guy who has done a lot of Brit transmissions, and ran the symptom past him.
Wear on the dogs of the gear and inside the synchro ring.
He says the shifter movement is a wear indicator, and a pre-cursor to the trans eventually popping out of gear on long trailing-throttle downgrades.
Fix is a new synchonizer and third gear.

That's what he says.

Not me, altho it fits into my experience with worn dogs on the gear and worn synchronizers.

Still, if it works, drive it.
It isn't going to quit.

My experience with second being the "torque" gear works with U iron, but LBC's, third is used more, and experiences this kind of wear.
He said if it's only 3/8" at the knob, you're in good shape for a long time.
Next rebuild, new third gear and synchronizer.

Dave
 
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