gearbox stuck in reverse(I think)

[outage]

Had the engine,clutch and gearbox removed to changeout clutch(as it was slipping on acceleration) and replace all seals. Replaced all components, reinstalled and took it for a test drive. Rear engine rope seal leaking excessively. Removed engine etc, replaced rope seal, tested in situ with oil in engine and hoisted to 45 degrees- left overnight and no leaks. Reinstalled engine etc again and found gearbox locked in gear( reverse maybe as unable to move shifter only sideways).Clutch ok as shafts turn when in. Any suggestions??
Also removed and reinstalled starter motor after cleaning. Get a click sound but engine won't turn over. Recharged battery but same situation..
regards Alan from Canada

[johnetype]

For your second problem with the starter motor, check your engine earth strap(s) have been refitted. The starter won't turn unless the engine is connected back through to the battery.

[angelw]

Hello Alan,
The only seals associated with the Gearbox is the seal in the Bell Housing for the First Motion Shaft and the Seal in the Oil Pump Housing, both able to be replaced without dismantling the Gearbox. Therefore, the question is, what work did you carry out on the the Gearbox?

Regards,

Billl

[mgcjag]

Hi Alan.....has the top cover been off the gearbox....Steve

[christopher storey]

Don't keep trying that starter. Your symptoms sound as though the selector detents have become misaligned and you have managed to select two gears at once ( a rare but known hazard particularly on the Moss box) which locks the box solid. You need to take the gearbox sheet metal cover off, and try to inspect the position of the selector rods. I can't give you chapter and verse, but others may be able to do so . You could prove this by trying the starter with the clutch pedal fully depressed - if it then turns over your gearbox is locked

PS it would help if you tell us what model you have

[outage]

I re-cleaned the terminals and connections on starter and car now starts!!!Yeh!!
I have a 1969 e type jag convertible.British racing green with tan interior.
Gearbox..it is definitely stuck in reverse. The backup lights on when car started and when I let out clutch, off we go in reverse. Do you think this can be rectified without gearbox removal?? Suggestions welcome!!
regards Alan from Canada

[outage]

I forgot to mention that no work was done on gearbox and the lid has not been removed. I am a little nervous about removing lid as no experience with a transmission and don't want to totally screw it up. I know it has to come off to see inside but will wait for any suggestions from the forum before doing so. Really appreciate any input..
regards Alan

[mgcjag]

Hi Alan....I dont know enough about the gearbox to help with the internals but a basic start without removing the cover would be to look at the gearchange lever right at the bottom where it connects into the gearbox....has something got jamed in there like a loose nut or something from where engine was reinstalled in the car....you will have to remove the center console and tunnel cover to look....Steve

[outage]

Hi Steve....looked at assembly below gear shift...nothing seems out of place and appears nothing stopping motion
regards Alan

[angelw]

Alan Wrote:

looked at assembly below gear shift...nothing seems out of place and appears nothing stopping motion

Hello Alan,

You state in your first Post that the Gear Lever can be moved side ways; that would indicate that the Gearbox Selector Rods to be in the Neutral position. The following pictures show the correct location (below the gear shift) of the Selector Rods for Neutral.



If Reverse was selected by its Selector Rod, the End of the Rod (Right most Rod in the picture) would be in the Forward position and sideways movement of the Gear Lever would be inhibited. Accordingly, if the Selector Rod position are as shown in the picture, then Reverse Gear Lever has independently moved the Reverse Idler Gear, or the Reverse Idler Gear has moved independently to the rear to engage Reverse Gear.

The following picture shows the location of the Reverse Gear Lever in the Gearbox.



Given that you haven't had the Top Cover off, then there will be an issue with this lever, or the Reverse Gear Selector Yoke that engages with the pin at the top end of the Reverse Gear Lever, shown in the above picture.

If the Selector Rods are as shown in the attached picture, you have no option other than to remove the Top Cover and probably no option anyway. When you get to the cause and rectify, the Selector Rods in the Top Cover have to be in the Neutral Position and the Reverse Gear Lever in the Gearbox to the rear (Reverse Idler Gear forward in the Neutral, or Forward Gear position) when replacing the Top Cover. You need to be certain that the Yoke on the Reverse Gear Selector Rod engages correctly with the pin at the top end of the Reverse Gear Lever. I use a small mirror to view this engagement through what will be a small gap between the underside of the Top Cover and the Top Surface of the Gearbox Housing.

Regards,

Bill

[angelw]

Hello Alan,
The following picture shows the Top Cover inverted displaying the various Selector Rods. The one of interest to you is the one on the Left in the picture and the component in particular, the part indicated as Reverse Gear Selector Fork. This engages with the Pin at the Top End of the Reverse Lever shown in my previous Post. The picture below also shows the alignment of the slots in the Selector Rod Ends when Neutral is selected.



With the Selector Rods in the Neutral Position, as seems the case from your earlier description, the only way Reverse gear can be selected, is for the Reverse Idler Gear to move to the rear independent to the movement of the Reverse Gear Selector Rod in the Top Cover. This could only happen if the Reverse Lever has become unattached from the Gearbox Housing, or the Reverse Selector Rod in the Top Cover, or the Reverse Idler Gear, or any combination of the three previous alternatives. The reverse Idler Gear and its position when Neutral, or a Forward Gear is selected is shown in the following picture.



1. The Reverse Idler Lever becoming unattached from the Gearbox Housing can be rectified with the Engine and Gearbox in place.

2. To become unattached from the Reverse Selector Fork in the Top Cover, either the Pin at the Top End of the Reverse Lever, or the Reverse Selector Fork would likely be broken, or damaged in some way. Depending on the damage and what you find, the Gearbox may have to come out to ensure there is no unwanted debris in the Gearbox Housing.

3. To become unattached from the Reverse Idler Gear, would probably require the yoke at the lower end of the Reverse Lever to be broken off. A cotter pin holds it in place, but losing this pin would not let the Yoke to become disengaged from the Reverse Idler Gear. Anything broken at the Lower End of the Reverse Lever is likely to require the Gearbox to come out to fix.

If the Reverse Lever needs to be replaced, it can be with difficulty with the Gearbox in place, but you would need to be very confident that all debris from Gearbox Housing had been retrieved.

Regards,

Bill

[christopher storey]

Bill : we don't know which gearbox the original poster has. Which one are you showing ? Moss or all-synchro ? It looks to me like all synchro from the position of the reverse lug but I am no expert on boxes

[angelw]

Christopher Wrote:

Bill : we don't know which gearbox the original poster has. Which one are you showing ? Moss or all-synchro ? It looks to me like all synchro from the position of the reverse lug but I am no expert on boxes

Hello Christopher,
The Thread is Posted in the Series 2 Chapter of the Forum; accordingly, the assumption would be that the Gearbox is an all synchro. The pictures I've Posted are of an all Synchro Gearbox. If the OP declares that the Gearbox is a Moss Box, I can Post the same pictures for that Gearbox. However, the same principles apply for both versions regarding being stuck in Reverse and the Selector Rods being in Neutral.

Regards,

Bill

[outage]

Thank you all for the input into my problem. I am happy to report that I put a screwdriver in where the reverse rod is located and it withdrew without any issue. All 3 rods are now in line and gearbox works correctly. Could not have "quick fixed" this problem without all your input. Thank you!! The drawings plus written feedback really helped..
thanks again everyone
Alan from Canada
now to reinstall bonnet and consul and then lots of detailing...plus some nice weather!!!

[angelw]

Alan Wrote:

reverse maybe as unable to move shifter only sideways
and
looked at assembly below gear shift...nothing seems out of place and appears nothing stopping motion

Hello Alan,
Glad you were able to dodge the bullet.

Your comments above are a little confusing, particularly only being able to move the shifter sideways. With the Reverse Selector Rod in the Forward (reverse) position, you should not have been able to move the Gear Shift Lever sideways. Also, the Gear Shift Lever is a quite a good tool for levering the Selector Rods to various positions and would have similar mechanical advantage to that of a screw driver (depending on the length of the screw driver, or if you were using the taper of the blade rather than the screw driver as a lever). If the Selector Rod moved with the aid of a screw driver, its surprising that it wouldn't move with the Gear Shift Lever.

Regards,

Bill

[johnetype]

Bill,

All true but you need to allow for the possible effect of the reverse detent ball and spring which can "seize" up after a period of none use and make it appear you can't engage reverse. Secondly if you reinstall an engine and gearbox without the gear lever in place and during that process accidentally knock the reverse selector rod in, when you subsequently install the gear-lever in the neutral position it will appear as though you can't engage reverse because reverse is already engaged.

Using a screwdriver gives you a similar mechanical advantage but because it is used to bear on different places on the rods can appear to move rods when the gear-lever can't.