+2 5 speed gearbox jammed.

[Mick6186]

I am currently rebuilding a 1973 elan+2 130/5. When checked the gearbox appeared in good condition with no undue wear or obvious damage. On the bench all the gears selected but the change was a bit stiff and vague. At this stage the oil had been drained. I re-installed the gearlever and have now replaced the engine & gearbox in the car and filled the gearbox with redline MTL oil. The problem I now have is that when I engaged second gear the box appears to be locked in two gears at once. The first time this happened I was able to free the box by moving the propshaft back and forth at the diff end, but now it is well and truly jammed and I am unable to turn the prop. I have not yet run the engine and am now prepared to remove the box to investigate. The problem I have is that I cannot move the propshaft to undo the diff end, which has to be done in order to move the gearbox forward to undo the gearbox end.
I would be interested to hear any thoughts as to what the problem with the gearbox may be (I am thinking a selector fault) or possible ways to free it to enable me to undo the prop.
regards,
Mick.

[Mick6186]

I've now removed the gearlever and selector top cover plate to see if there's any obvious fault. Everything seems ok with the ball of the selector rod in its socket, but there is not even a millimetre of movement in the linkage when trying to engage neutral!
The engine turns over as normal with the clutch normal or engaged, and there is no movement of the prop, so whatever is jammed, it appears the box is in neutral!
Any suggestions would be gratefully received. I'm still trying to work out how to remove the prop.
Mick.

[rgh0]

For the output shaft to be jammed but the input shaft free to turn suggests some major internal failure. I would try to get a spanner on the output shaft and see if it can be worked back and forwards enough to get at all the prop shaft nuts.

Alternatively I would think with some effort and maybe some specially bent spanners you should be able to get at all the nuts on the rear connection to the diff even if it cant be turned.

Another alternative The sliding spline also comes apart so you could try that also. I have never pulled one apart so not sure how its done but there is a cap that looks like it needs to be unscrewed then it should just pull apart.

cheers
Rohan

[Mick6186]

Hi Rohan,
Thanks for the reply. I think you're correct and I'm going to have to thin down some ring spanners to make it easier to get on the prop nuts from a different angle. I'm hoping that my problem is a selector fault, possibly a circlip come off the reverse /5th lever pivot & jammed the lot (I am an optimist!!). I'll report when I find the problem.
Mick

[Mick6186]

Rohan,
I managed to remove the prop shaft bolts by grinding down the thickness of the ring of a ring spanner and getting it on the bolt heads.
The gearbox is now out and I have discovered a schoolboy error. The box was previously filled with EP80 gear oil and I was replacing it with Redline MTL so I drained the box and had the great idea of washing it out with de greaser (mistake!!).
The box had been left for several months with no oil in it and it appears the first selector shaft and interlock plates had gone rusty and siezed once the shaft was moved through the ali casing. Once cleaned up the box appears to operate normally.
The first selector rod seemed the worst affected as it passes through the casing and I think it jammed as it went between gears.
The rest of the box seems fine.
Mick

[rgh0]

Hi Mick

Good you found the source of the problem

cheers
Rohan