3. what is wrong with transmision/torq-conv on my Jcb 3cx 2 wheel dr.1981?

check the dump pedal again press your foot right down the make sure you can get a 20 p in the gap
or remove the sump check the strainer isn't blocked

dave m
May 2009

Hello
I must admit that I am not familiar with the g/box internals. I wouldn't have thought that the forward/reverse clutches would have both failed at the same time.
I'm not sure we are talking about the same thing! I take it that what you refer to as the "clutch" is the dump pedal (operated by the left foot, on the cab floor, behind the brake pedals? Crawl underneath the m/c on the near side, and you should see the end of the dump pedal. From this there is a rod which connects to an "L" shaped lever on the side of the g/box. If you pull the rod you should see the plunger of the dump valve move out of the bushing in theg/box side. It will look clean and shiny. Release the rod and the plunger should then return fully. If, when released, you can still see any shiny shaft showing, then the plunger has not returned fully. Check that return springs are intact, and that the linkage is free.
If needed, adjust the operating rod to give a little clearance. Note that only a small movement of the plunger will "dump" the torque convertor flow, resulting in no drive.
Hope this is of help, as I can offer no advice on the internals of the g/box - sorry, but mine hasn't broken yet, so haven't ever needed to go further than torque conv. oil level and dump pedal adjustment!
Good luck!

Mr. Toad
May 2009