Gearbox jumps out of first ( 1st )

[john116]

Hi - need some help with an FB original gearbox. (Have also posted on the FB/EK site). It keeps jumping out of first gear, is ok in second and third.  Have tried adjusting the gear rods as per the manual, but didn't seem to help.

Also, the gear shift selector lever doesn't seem to lock into first (doesn't 'catch' would be the best way to describe it.

Anyone have any suggestions - what to do, how to fix it, what to look for...


Thanks,

John

[RET]

If it won't catch first gear properly then that certainly explains why it pops out again.  Has the gearbox been out recently?  One of the GM-H service bulletins describes how this phenomenon can be caused by the gearbox not being aligned perfectly with the motor.  Of course, if it's never been out that's unlikely to be the problem, and you're going to have to persevere with the linkages etc.

Another thought.  Check your engine mounts.  I had a problem with my very first FC where it was jumping out of gear sometimes, and it was a worn  engine mount that was putting strain on the linkages.  I only discovered this after shearing the shifter tube  :-/

Hope that helps,
RET

[mcl1959]

Jumping out of first is also systematic of being worn out, may be easier to get another box and replace.  A few of mine have developed this problem over the years.

Ken

[normd]

John
   Had the same trouble with my XK  mmm , yea , bout the same vintage , in 1970 ,   gearbox rebuild and no more probs

    Norm   :)

[EJ_Dave]

RET,

I'd be interested in finding out more about imperfect motor-gearbox alignment. My box has jumped out of third intermittently since I separated and rejoined it  from the motor when it (motor) was rebuilt. Could alignment cause this or does it only affect 1st? How do you make sure alignment is correct?

Dave

[zulu]

Dave, This happened to me once with my 1st FC, it turned out to be a cracked extension housing, the long bit on the back of the box, check that the attaching bolts are tight.
Gary  

[RET]

Dave,

Did I hear that you were at Jindabyne?  Sorry I missed you.

I'll find that service bulletin and post the details for you.

cheers
RET

[EJ_Dave]

Thanks RET.

Yes, I was in Jindabyne on the Saturday and thoroughly enjoyed the day.

Cheers,

Dave

[RET]

Found it.

TOP GEAR SLIP-OUT - 'FC'
After ensuring all the normal checks have been carried out relevant to top gear slip-out, check the four (4) transmission to engine assembly bolts to ascertain if they can be removed from their location without any apparent binding.
Investigations on some current assemblies have revealed that when the transmission is offered up on the dowels, the threaded holes in the cylinder block are not in true alignment with the four (4) transmission attaching holes, which is causing binding of the bolts and resulting in misalignment of the transmission assembly to the cylinder block.

Note:- This condition must not be confused with misalignment of the dowels and under no consideration must the transmission dowels be reworked.

To correct the misalignment condition, relieve the four (4) attaching holes in the transmission, so that there is no interference between the transmission case hole and the bolt, as the bolt is screwed into its location in the cylinder block.

Don't know if that's any help to you or not, but it's probably worth checking next time you're under the thing.  Whatever QA problem was causing this must have been fixed by EJ though.

cheers
RET

[EJ_Dave]

Thanks RET,

I will have a look. The gearbox in the EJ is different to earlier grey boxes having a separate bellhousing perhaps giving twice the opportunity for alignment to be out a bit. I have heard that mis-alignment can cause this problem in EH/EJ too but hadn't seen any technical information. Although the 'box is different the FC article would tend to support this.  

A solution suggested to me was to loosen the bolts a bit, drive around the block and then tighten them up again.  Didn't work for me but it may help someone.

Cheers,

Dave