I am thinking Speed Sensor but just want to make sure. I have a 2000 Dodge durango 2wd. Has about 75,000 miles on it. I am experiencing a very hard shift from 1st to 2nd when the engine is cool. Once it watms up, I do not notice the problem. Going from 2nd to third there is no problem or downshifting there is no problem. Just from 1st to 2nd when it is cool.

Speed Sensor?

Thanks

 

What's your line pressure during a 1-2 upshift?
Could also be a blown shift actuator fuse!
Kinda hard to diagnose this one unless you really know automatic transmissions.