It is great that item comes with a sleeve to help installation go smoother, however item did not fit. Spent 2 hours trying to fit, but constantly failing. By chance noticed that I was not alone fighting with 40644 part. Luckily had different seal as spare and that went in easily. Would not by again even though the quality feels good. Quality doesn't fit, which is a shame.
The original seal wasn't leaking at all at 170k miles, but decided to replace the main seal for 2005 F150 4.6L V8 4x4 while transmission is out. The seal is actually made by the National seal in USA with Fel-Pro package. This seal looks and feels a lot like the main seal I installed on the Cummins 5.9L common rail diesel engine many years ago. I feel better about choosing the PTFE upgrade over the standard material especially the price was only $16 with shipping included from Puerto Rico. Autozone had the same seal for $23 before tax but I really wasn't in a hurry. I got it in the mail in 5 days. The actual transit time was only 3 days.