Thread: TD6 bogging down going uphill in 5th

Had trans oil changed and now having problems in 5th gear.
Have oil dropped and new fluid in every 20 thou k,s usually around 6.7 lts give or take.
When going along the flat its fine,but start going up a hill it seems to be getting bogged down with no power until it drops a gear or two then it picks itself up.
Am wondering if its g/box related or engine related.
From a stop it goes like a scalded cat,but when in 5th you put your foot down to go up a hill and theres just no power.
G,box was recon,d by well known GM/Rangie specialist 6 years ago and he recommended drop the oil every 20thou k,s(which I have been doing.)
Any ideas greatly appreciated.

DG

Took it into my mechanic today and it was a perished boost/vacuum hose.
Have now got FULL power back in the beast.
Happy camper once again.

DG