Tranny Rebuild Issue

I am doing a transmission & motor rebuild on my '75 Mark lll.

I re-assembled the tranny last night & it went together nicely but will only shift into first and second gear. In other words, I get neutral, 1st & 2nd.

It' needs to be dis-assembled but I would like some thoughts on what I should be looking for? Like I said, it all seemed to fit, slide, etc OK.

It there anything different with the Mark lll gear & forks set-up? (Not the obvious difference in output shaft)
Stephen

Before you second quess yourself make sure that you are turning both the main shaft and the sleeve gear while doing your selection check; the gearbox doesn't like to shift if it isn't turning and sometimes it needs to turn a lot to be able to engage the next gear.

However...

If your shift forks are properly engaged/oriented your quadrant/cam plate may be out of time. When I assemble a gearbox I put the cam plate in either 1st or 4th position and assure that the quardant just clears the top or bottom, respectively, of the "window"in the inner cover. Make sure that 3rd gear mainshaft is oriented correctly it will fit both ways, but permit shifting only one way.

RS

Your camplate is a tooth off. I did the same thing on mine. It's not hart to get it off a tooth. There is a good picture in the Haynes manual if I remember.

Once the inner cover has been refitted, it's always a good idea to ensure that all gears can be selected-by levering the quadrant through its full operating range in the inner cover slot (whilst simultaneously rotating the mainshaft) before refitting the outer cover.

Go to the Old Britts site and into their technical articles. There is a huge amount of great info with pictures re all this and much detail/pics re camplate alignment. The link to them is down toward the bottom of the "Norton Links" at the top of this page.

The quadrant may be "geared" satisfactorily even though it doesn't allow the forks to locate in the tracks correctly when the spindle is inserted--I have to move the quadrant slightly beyond the fourth-gear detent in order to get the forks to line up in the right tracks and accept the spindle.


Tim Kraakevik
kraakevik@voyager.net
Three Commandos

I agree with L.A.B. the time to test gear engagement is before you put the outer cover on. Make sure the lever does not hit the edges of the inner case and will not go into 4th or 1st. You can move it with a large screwdriver. Hemmings even suggests relieving the inner case edges (both) a bit as I remember.

Dave
69S