hi there, I'll add to
stihlhead517 above, as he has managed to tell you the actual drift tool needed if wanted.
the 372xp has a rubber O-ring that must be seated correctly before the sleeve goes on. Use a bit of flange sealeant on the inner side of the sleeve, just a little squirt and use a small scredriver to gently run the sealant around the sleeve,
The sealant you used will be on the outer facing side of the sleevel, so do not put the sleeve on with the sealant on the inside side where it buts up to the O-ring rubber seal. It should be on the part of the sleeve sticking out, NOT against the rubber O-ring side.
The sleeve has to but up against the seal.
The reason for using flange sealant on the sleeve is simple. It gives more hope of a seal against any air leaks. Also you turn the sleeve on, do not simply push it on.
I hope the pics help you see what is done and what is needed to help you in this.
These saws are one that can leak air past this O-ring, and chinese saws do not even have the rubber O-ring and people think it is the carb giving bother.
This side has to be air tight beyond what the actual casing seal does.
The actual crankshaft seal drift tools used you can use anything that will fit over the seal and flange, like a thick flat washer, then a socket to drift the seal in.
You are looking to drift the seal flsuh with the actual casing, nothing else, both sides.