Jumping out of reverse?

[simo66]

My 1980 105 Spider has started jumping out of reverse

Very light weight from my left hand on the gear lever stops it happening but can make reverse parking a bit difficult!

The car had a ground up resto just before I bought it and has only done about 4000k's since

I spoke to one mechanic who reckons the gearbox needs to come out to fix it, but that sounds rather expensive! Is this the only way or is there an adjustment that could be made? It just seems like a linkage problem to me...

Cheers, Simon

[Anthony Miller]

More like a selector fork problem and yes the box does have to come out

[cjheath]

The idler gear (or one it engages with, I forget) gets worn on one side, so the tops of the teeth (which should be rectangular) become trapezoidal. The result is that you can reverse for only a metre or two before it jumps out. If you hold the lever, it stays selected, just as you say.

I have this problem in my gearbox, which was supposed to be a fully reco'd box when I bought it from Alfpa. Hugh has promised to fix it, but I didn't insist he pull the gearbox specially, instead I'll get him to do it when next I do a clutch or have the gearbox out for some other reason.

So yeah, the gearbox has to come out, but once it's out, it's not a major repair.

[aggie57]

Before you go pulling the gearbox out check to make sure the console is letting reverse select fully and that the reverse lock out (in the top of the gearbox, accessible from inside the car) is working correctly.  Both are common causes for this.

[simo66]

Before you go pulling the gearbox out check to make sure the console is letting reverse select fully and that the reverse lock out (in the top of the gearbox, accessible from inside the car) is working correctly.  Both are common causes for this.

How do you go about doing the above?

Many thanks for all the replies by the way!

[ralph2007]

no idea about the mechanics of it, but my '68/69 continually loses reverse. 

[aggie57]

Before you go pulling the gearbox out check to make sure the console is letting reverse select fully and that the reverse lock out (in the top of the gearbox, accessible from inside the car) is working correctly.  Both are common causes for this.

How do you go about doing the above?

Many thanks for all the replies by the way!

Put it in reverse and make sure there is still a small gap between the gear lever and the inner edge of the console.  I found a couple of threads on alfabb that discuss this:

http://www.alfabb.com/bb/forums/spider-1966-up/4370-pops-out-reverse.html
http://www.alfabb.com/bb/forums/spider-1966-up/99133-clutch-pop-out-reverse.html

[1750GTV]

More like a selector fork problem and yes the box does have to come out

Have to agree. If you can engage reverse and then as you let out the clutch, it jumps out of gear, then it's a bent selector fork.
The other common concomitant is worn synchro on second gear.

Only cure is a gearbox stripdown and rebuild. I hate to say it, but maybe the groundup restoration skipped a few bits.

Chris

[alfa75gta]

My Berlina continued to jump out of reverse until I took out the console (as others have stated) and loosened off the rubber boots at the top of the gearbox.  The combination of the 2 rubber boots and the leather gaiter seemed to be too much opposition for the selector, when in reverse gear due to the leaver being pulled down so far to the right side.  One of those rubber boots is quite hefty!

[simo66]

Many thanks for all your replies!

I had a quick look yesterday and the lever doesn't seem to engage as well in Reverse as 2 and 4. It does seem to be restricted by the leather gaiter and/or the console and is easy to knock out of gear with very little pressure (car running or not). I'll loosen the console at some point and see if that helps!

My mechanic told me that it could be a bent selector fork but also suggested the console/gaiter would be well worth investigating first.

If not I'm going to live with it until something else needs doing on the gearbox!

Simon

[cjheath]

When you do loosen the console and try it, if it still jumps out of reverse, you may be able to identify it as a worn gear rather than a selector. With a worn gear you'll always be able to reverse about the same distance (a couple of metres) before it jumps out, because the wear makes it "wind its way out" over that distance. If it jumps out straight away, or at different distances, it's more likely a selector.

The selectors are very strong, you're unlikely to have bent them (though mechanics who aren't Alfa specialists might not know that; some other cars are more prone to it).