Jeep 2.7CRD gearboxes. No faults but slipping

[Jon-yn7gm]

My Jeep Grand Cherokee WJ 2.7 CRD has very little pulling torque until your foot is more than half way to the floor. A gearbox specialist in Bristol has said there are no fault codes coming up and have just said it's slipping. I've heard that these gearboxes don't go wrong but this one was rebuilt about 40k miles ago.
Does anyone have any suggestions as I'm told that there's nothing that can done short of rebuilding the box and transmission again or replacing
All comments welcome
Ps my other Jeep with the 4.7 V8 is as sweet as a nut!
Jon

[cptsideways]

An Aisin box on these I think. Solenoids would be my guess.

[tr7v8]

It's a Mercedes box I think a 722.1 if my memory works. Various faults on these worth joining the WJ Forum on Face book as a huge amount of knowledge there on it.
Guys seem to be having issues with the selector PCB being one.

[pcn1]

Ive got the same jeep. Not had a problem as such but a weak battery once caused the box to stick in low gear. Also they do need a full oil change at this age, merc originally said sealed for life but that proved false. I did mine as a preventitive.
Lastly I heard oil can wick up a electrical cable and cause problems with the box ecu. You can get an oil seal from merc to stop this.

Hope that helps