same here my guage barely moves off of 100, if I get stuck in traffic then park it for a few minutes at a store or whatever I come back out and start driving it will move off of the 100 degree mark but not much, by the way make sure you add some tranny fluid you might be a half quart down or so after you install bigger cooler, I think I was down almost a full quart

 

This isn't my first rodeo, first thing i did, after it was all setup, was to add a quart of fluid...

 

the add a quart part was intended for thread starter since he was about to do the install