Benford TT2500 loss of power

[Bede Mullen]

Hi my 1984 TT2500, which I use daily, has suddenly developed a problem. It has lost power/compression to the extent that it needs a push with the digger to get it moving from a dead start and it struggles going up any incline and often jumps out of 1st gear if there is a load in the skip. Curiously it is OK in reverse. Any ideas gratefully received