What do you all have your idle set at with the 455?

I set mine to about 750 in park, which turns into about 550 or so in drive.

However, when shifting from park to drive at about 750 the car tries to jerk forward, is this normal for a stock TH400? It has pretty firm shifts all the way through when driving, but never noticed the hard shift to drive until adjusting the idle up. It was too low before, I had it at about 550 in park and in gear it sometimes felt like it wanted to die when hot, so I had to turn it up.

Normal for this transmission?

Thanks.

 

That has more to do with the torque converter than the transmission. It's all in the stall. Because you have a land yacht it has a tight converter (lower stall speed) and thus doesn't slip as much. This is what is causing the lurch into gear with the higher idle speed. You'll need to check the specs for your engine as to what it is supposed to be set to both in gear and park.

 

Your idle speed should be 650 in drive, disregard what ever it's running in park. If your getting a severve clunk, you might have a ujoint going bad.