Team-BHP - MAN TGA 430 - Engine won't rev in 5th gear

I own a MAN TGA 430. We had recently fitted new liner to the clutch plate and facing done to the pressure plate. Since then the vehicle works perfectly upto 4th gear, able to pull loads of upto 150MT, but when shifted into 5th gear, the engine becomes unresponsive and sits at the idle RPM. Pressing the gas pedal has no effect on engine. If now shifted in 4th gear, the engine once again becomes operational.

The service center guys adviced us to change the clutch plate, claiming that the liner fitted by us is unable to handle the load. But the fact is that the vehicle is able to pull heavy loads upto 4th gear, but when in 5th gear, even the Puller alone is unable to move.

We think that this should be some electronic issue. Some sensor may be reporting that it is unsafe to increase speed beyond a limit. I don't know what this sensor could be. If someone knows a way to troubleshoot the problem, please help.

Which gearbox is on the vehicle, 16 speed one with manual shift? If so please check when you change the range switch, any error is shown in the dashboard. Without trailer tga can be started in 5th gear itself. Also check the air pipes to the gearbox are connected properly.

Definitely this should not be the case with lining as you have clearly told even tractor is unable to move while shifting to 5th gear. This is purely a sensor issue. Check for relay or any sensor connecting GB which gives signal on movement of fingers. Malfunction of this makes engine to understand GB is in neutral.