Hi everybody, i put in a second hand gearbox in on saturday which came off an F reg escort rs, also put in a new ap competition organic clutch with it, now i have a problem which im hoping its not the box, it keeps jumping out of first gear. everyother gear is perfect, i also replaced the linkage. all the gears go in very smoothly apart from this issue of jumping out of first on take off. what can this be synchro gone or going?? it also doesnt happen all the time, sometimes first gear may stay in? im going crazy thinking about it.

can it be anything elese like linkage adjusting??

i was told it had a LSD, which is the best way to test this?

please advise.