Gearbox reverse woes.

PostPost by: davidj » Tue Jun 07, 2016 11:50 am

Good afternoon.

I originally posted this message in the +2 section, but I thought I would see if anyone else has any ideas as the gearbox was common to all elans.

My 4 speed gearbox will no longer go into reverse. The lever pulls up and across into the gate to the left but is being restricted to moving back to the rear of the car to "slot" into gear. This is even if the engine is not running. Forward gears work fine. It was ok until I attempted to reverse out of my garage last Thursday!

The nylon cap does not seem loose and the gearbox does not have a reverse light switch, which appear to be the cause of most of the problems with the gearbox not going into reverse

Does anyone have any suggestions?

Thanks in advance.

David
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PostPost by: rgh0 » Tue Jun 07, 2016 12:37 pm

Assuming the lever is selecting the reverse gear selector rod OK which it sounds like from you description but failing to be able to move that rod then :

1. It could be the mechanism that moves the reverse gear idler into contact with the gears on the output shaft and layshaft is jammed

or

2. It could be that the interlock mechanism for the reverse gear selector rod is jammed and not allowing the movement of the selector.

Either is a gearbox out job I am afraid as you need to take off the top cover to see whats going on.

cheers
Rohan
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PostPost by: gus » Tue Jun 07, 2016 12:50 pm

I guess I would do this if it were me:

start the car

put it in first, ease out the clutch so the car moves a bit

try to firmly put it reverse. not forcing it but using a firm hand

repeat with every gear

the reasoning is I am thinking one of the little interlocks is stuck or out of alignment, or the detent is slightly out of place. exercising it may pop it back into place.

The detents are held in under the front edge of the transmission cover. The interlocks are in a passage at the front of the case perpendicular to the 3 rail bores and intersecting them. They look like little 'good&plenty' candies. None of it is accessible in the car.

If this does nothing, shift boot off[usually console out] unscrew the ball, shift to neutral remove shifter. Look at the shifter rails through the hole. the notches should be aligned in a row or you are not in neutral. The rightmost is the reverse rod. With the car off, you should be able to push it forward with a large screwdriver, you may have to rock the car. Try the others[and put them back to neutral] to get a feel for the effort required, the shift lever gives you a lot of mechanical advantage.

If it does move into reverse, then there is something in the shifter and you should be able to figure it out easily

If it does not, looks like gearbox out..............
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PostPost by: ricarbo » Tue Jun 07, 2016 1:42 pm

If you're lucky, I believe it could be the reversing light switch out of adjustment and blocking selection.
regards
Richard
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PostPost by: gus » Tue Jun 07, 2016 2:20 pm

he aint got one....
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PostPost by: davidj » Wed Jun 08, 2016 11:45 am

Thanks for your comments. I will give them a go over the next few days. I really do not wish to pull out the gearbox! Unfortunately there is not clearance to remove the nylon cup without making the hole in the fibreglass transmission tunnel a bit bigger, but I guess (hope) this would cause any major structure problems to the body.

You are correct; I don't have a reverse switch. Don't know why as the car has reversing lights! I can only guess a po switched the gearbox sometime in the dim and distant past.

Cheers,

David
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PostPost by: gus » Wed Jun 08, 2016 1:37 pm

Funny, while there is variation, my car has a formed rubber shroud riveted to the body that conforms to the ball. Removing it[its actually in a box for years, a plain sheet of rubber in its place] leaves a 2"x3" ish opening though which with some difficulty one can extract the shifter.
In fact, it must be so,as you really cannot get the gearbox out otherwise
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PostPost by: davidj » Wed Jun 08, 2016 5:57 pm

I uploaded a picture of the clearance around the gearstick in the +2 forum. I would think it is a bit smaller than 3x2 and needs to be made bigger to remove the rubber shroud. I have not actually worked out what is holding the shroud in place but the manual shows a metal plate.
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PostPost by: gus » Thu Jun 09, 2016 11:20 am

Boy it has been a long time. I thought mine was riveted to the body,but maybe it was the chassis, maybe it came out the first time I had the chassis out.

At any rate I see no rivets poking through so I think you are safe cutting with a multi tool or small dremel etc to enlarge the fiberglass
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