[R0verLuver1]

I've got an odd problem with my '03 Disco 2 that's slightly worrying. The issue has occurred 4-5 times, only one time per trip. The issue is also not biased towards any particular driving scenario. It's completely random. While driving, a loud 'clunk' can be heard, and the whole truck jerks as if the transmission slips into neutral. Simultaneously, the engine light flashes on, then off. It only happens for a second than continues on normally... well it did until today. After the clunk occurred, the transmission slipped into rescue mode. The "S" and "M" lights, the "D" on LCD screen, and the gear indicator light on the console began to flash. If I recall correctly, the transmission defaults to 3rd gear in this rescue mode. Anyway, what could be going wrong here? Is this a wiring/electrical issue, or is the transmission giving out. OR is the transmission just low on fluid. Thanks in advance!

 

[redtruck12]

Low fluid will usually give you a slip or late shift but not a clunk. Checking the fluid to be sure may not be a bad idea but you description sounds like a crank position sensor on its way out
Read up on crankshaft position sensor faults and trouble ( common fault)
I think you will find it matches your issues.
Left unaddressed it will likely become a quit while driving or cranks but will not start so don't ignore it

 

[R0verLuver1]

Low fluid will usually give you a slip or late shift but not a clunk. Checking the fluid to be sure may not be a bad idea but you description sounds like a crank position sensor on its way out
Read up on crankshaft position sensor faults and trouble ( common fault)
I think you will find it matches your issues.
Left unaddressed it will likely become a quit while driving or cranks but will not start so don't ignore it

Thanks for the help! I'll look into both.

 

[R0verLuver1]

FOLLOW UP: I checked the transmission fluid level, and it was fine so I went out and purchased a new CPS from Advance Auto. It took me about 2 hours with my hands jammed up between the exhaust, frame and block, but I managed to swap the sensors. Not only did it fix the clunking issue, my rover runs much smoother. Its probably safe to say that the sensor that I replaced was the factory sensor, and since my Disco has almost 160k, it makes sense that it was end-of-life. Thanks again for your help redtruck12!!