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MG MGA - Yes, again - No Reverse Gear

An old topic, but this one is odd.

A pal of mine has put his pushrod MGA Gearbox back in after a long resto, during which time the box was overhauled by a third party.

There is no reverse gear when the remote turret is in place - there is no feeling against the spring resistant detent and the stick won't go backwards to engage reverse. All four forward gears are fine. The rectangular cover panel on the box that is often fitted wrongly is in place correctly, with the bulge at top left. The spacer is fitted between turret casting and gearbox. A bush is in place in the selector mechanism.

However, take the turret off and, with a socket extension, you can engage all four forward and reverse gear and the car moves back and forth.

I took the gearbox turret off my old twin cam gearbox (which works fine) and put it on the pushrod gearbox - no reverse gear, no detent etc. I put the pushrod gearbox turret on my old twin cam gearbox and it works fine. Both spring detents on both turrets appear to work OK and have almost identical spring resistance.

Before hoisting the engine and gearbox out, has anyone got any ideas's?

regards
Colin
Colin Manley

Yes. The tin cover on the top of the gearbox has been fitted as shown in all the diagrams. This is unfortunately wrong by 180 degrees, so that the raised part that allows the lockout for the reverse gear is instead a flat section of the plate. The effect is exactly as you describe. Solution is to rotate the cover by 180 degrees, but this can't be done with the engine in the car. Maybe cutting out a section of the tunnel will give you access. You could make a larger plate to cover the resulting hole.
dominic clancy

Hi Dominic,
No, the panel is the right way round, bulge to top left (It is drawn bulge bottom right in Parts diagrams).

Also, I did cut an access panel in the transmission tunnel and took the whole tin panel off anyway. No difference.

With the remote turret off and no spring detent to worry about etc, I can swivel the selector to the right and then forward (as if I were moving the gearstick backwards if the turret was fitted) and reverse goes fine. Put the remote back on, no go.

What baffles is why there is no 'feel' of the spring detent when the stick is solid left and why the hell it doesn't work.

regards
Colin
Colin Manley

Try shimming the remote, at a guess if there is no spring reistance the selector is not engaging the reverse rod.
mog

Ref my initial post; Have tried the remote turret with the correct spacer fitted, with it removed and with further packing. No reverse gear possible at all: remove the turret and get reverse by direct operation of the selector. Nothing is bent or misaligned, yet this must be a geometry problem.

I'm at a loss on this one.
Regards
Colin
Colin Manley

Tis a fun one this: take off turret, select reverse on stick, select reverse on gearbox using socket extension and see it you can bolt on remote.
mog

mog,
Well, I engaged reverse with the turret off, and moved the car backwards under power. I left it in reverse and then fitted the turret (moving the gearstick so the bush would engage in the selector) and the car merrily went backwards under power. I then moved the stick to neutral and all I can get again is four forward gears.

The steel panel on the top side of the gearbox is completely removed.

I have no idea what to do now.

regards
Colin
Colin Manley

There is a fairly strong mechanical lock-out to keep you from accidentally going into reverse when downshifting to 2nd gear. The stick moves from right to left, from 3/4 to 1/2 sides of the neutral range. When in the left position of neutral, it may require a bit of a slap with the palm of your hand to move the stick left to the Reverse side of neutral before you can pull it backward into reverse. That is the way the reverse lock-out detent is supposed to work.

You shifted it into reverse with the shifter removed. Then installed the shifter while it was still in reverse. Then you shifted it into neutral. All is well. Just smack the shift lever hard left, and you should be able to shift it back into reverse.
Barney Gaylord

Hmm, I find I have to be v careful downshifting to 2nd to avoid clashing wit R!
Art Pearse

Art,
On my friend's car, the detent spring was extremely strong, requiring a very heft whack to get into reverse, as Barney suggested. Perhaps the spring in the remote turret is broken?

regards
Colin
Colin Manley

This thread was discussed between 09/07/2016 and 03/08/2016

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