Hello, i am a HGV mechanic and have currrently got a NQR in with auto trans fault. It came in the other day, plugged it in came up with faulty sensor, changed sensor today fault cleared. Now it seems as if it has to try 3 times to engage drive or reverse then logs a gear selector fault until neutral is engaged again. It does also log neutral switch as active fault at the same time but then clears. Iv checked all wiring, iv removed neutral switch and tested it with multimeter, checked all parameters on Texa and everything seems good.I’m starting to wonder if it is a internal fault, would really like some help!!
Thanks
Have you tried phoning the local isuzu dealer ? Will admit glad i don’t have to work on them
Does it need a oil change in the box and a filter that would make it slow. 
Could be a micro switch fault in the selctor shift
Nah,the NQR box is a manual box with a solenoid pack to make it work like an auto.
Thing I find with this box is, the cross-shaft for the clutch on the O/S is right next to the exhaust.
Because of the heat, the roller bearing for the cross-shaft dries out and siezes up.
So the spring pressure alone doesn’t release the shaft, and the vehicle is left with no drive.
Our solution is, fit a new shaft (the old one will be knaced by scoring), drill each end in over and across the shaft where the bearing sits, and fit grease ■■■■■■■.
The shaft becomes a service part, grease the shaft with one pump of grease per side, per inspection, and no further siezing problems occur.
Don’t go mad with the grease pumping, too much and it’ll get past the inner seal and put grease in the bellhousing.
PM me for photo’s and explanation, this is something we’ve advised Isuzu on.
I also believe that Texa is very good at pointing you in the right direction.
But shouldn’t be taken as gospel. Once it’s pointed you in the right direction, follow that up with mechanical fault finding (manual) skills. Don’t take Texa’s verdict as gospel !