Thread: Disco Auto lock up problem

Lock up fails to operate on occasions, been doing it on & off for since I have owned it. Brought at 88600 Kms & now is just coming up to 152000 Kms. Ive done the oil & filter thing many kms back but it still doesn't lock on occasions. All Ive been doing is pulling it back into neutral then into drive & 95% of the time it locks up fine. All other gear changes occur exactly when they are supposed to so Im assuming the governor is okay & its more likely to be the valve or valves that operate the lock up. As Im going to change oil & filter again I thought it would be a good idea to find these valves & try clean them up or do whatever to sort it out. Problem at present is cannot find any information regarding where these valves are in the control bank of valves or more to the point can they be got at without removing the valve bank & pulling it apart. I know the Hysteresis valve is a likely suspect but don't know if I can get to it without pull valve chest apart. Any advice on this would be greatly appreciated.

There is an older thread regarding lockup and mods to get the TC to lock up in 3rd.
ZF 4HP Lock up converter
The mob who do the valve mods are Manuel Automatics and they may be able to tell you how accessible the valve that controls lockup is.
Cheers
Mark