Transmission and Heat Exchanger Problem?

[ahadi]

Hello everyone,

I purchased this car when it was 90K so I don’t have any records if the transmission has been replaced/rebuilt. I know I have the ZF 5HP24 tranny, no sign of any leaks.

My driving pattern within the last 12 months is about 10 miles per day.

When my 2002 X5 4.4 reached 124K, I replaced the spark plugs with NGK as recommended by the dealer and replaced the radiator because the top nose was cracked. This summer I went for a long trip and due to traffic I had to made a hard stop then quick acceleration and guess what I felt shuttering.

Now, every time after 30-40 min of driving I felt slipping/shuttering between 2 & 3 gear. I also noticed there is a small coolant leak between the bottom of radiator connection with the Heat Exchanger (see below picture). It could just the O-ring requires replacement.

For sure, I need to replace differential (both) and trans-case fluids.

Questions:

(1) Do you know if the slipping/shuttering cause of heat from transmission system, because the symptom only happened after 30-40 min of driving (S mode)?
(2) How do you determine if the Heat Exchanger is malfunction?
(3) Can it be the Heat Exchanger not working properly and make the transmission system overheat?
(4) I read almost of the transmission issues thru this forum but I still think my situation has to do with heat or electronic issue not mechanical, what do you think?
(5) At current stage, should I get the transmission fluids replace?
(6) Will the reprogramming the module unit help?

Heat Exchanger
http://www.pbase.com/renem24/image/92719199