2000 X5 transmission shift is rough after 8 miles

[ajitverma]

Hello experts,

I have a 2000 X5 4.4i. The transmission was having a lot of issues while shifting down so I had it rebuilt. However, a few months later I started noticing a slight hiccup while slowing down at a traffic light or stop sign. This happens when the vehicle has been driven about 8-9 miles. It looks like when the transmission oil heats up it starts giving trouble, but I am not sure.

The transmission shop says it may be the transfer case. Replacing that is another expensive job. The vehicle has about 220K miles.

What do you guys think? Could it be the harness inside the transmission, which has a temperature sensor? How about the coolant thermostat or the oil cooler? Could they be the culprit?

Thanks for your thoughts/opinion/help.