Noise when shifting into park on replacement transmission

My daughter has a 98 4x4 that reverse went out on it. I bought a replacement 5r55e from gottransmissions.com (not recommended) and just finished installing the replacement transmission. Reverse works now which is a good thing as do the other forward gears. However shifting into park the gears grind until park is engaged. I've tried shifting manually with the arm on the transmission and it does the same. I should add that I'm testing without driveshafts attached in case that makes a difference.

Rather frustrated at the moment. Any ideas on what the issue maybe? Hoping for a simple adjustment rather than a defective transmission, but would not be surprised if it's the later.

So to answer my own question, driveshafts are important! No grinding with them attached.

coreyva said:

So to answer my own question, driveshafts are important! No grinding with them attached.

Click to expand...

I don't think this is much help, but on a rebuilt Comanche standard tranny I had done, it was tight synchronizers that caused grinding gears on mine. I had to double shift to get it to go in.

coreyva said:

So to answer my own question, driveshafts are important! No grinding with them attached.

Click to expand...

With no driveshafts the output shaft is free to spin. When you put it in park, the parking prawl is forced to stop it from spinning. It's like throwing the trans in park while still moving.

Oooh don't do that!