4.6is shifting hesitations between 4th and 5th

[mgmarsh39]

Ok guys,

I recently got my X5 back from the shop after having to overhaul the cooling system due to the water pump failing. Recently in heavy traffic, the thing has this weird hesitation between 4th and 5th gear. It acts like it wants to downshift and revs gradually (no jerking just revs) then it finally shifts into 5th. I've only noticed it going roughly 40-50mph.

If I run it in tiptronic mode it doesn't do this and will hold the gear with no hesitation.

Any ideas?? I just hope and pray this doesn't mean my trans is on its way out.

Thanks in advance!