I prefer to pull the case and the transmission my self, don’t have to mess with getting the motor back in the mounts, pulling the hood etc. plus if you get the transmission out on the Floor or a bench it’s easier to replace the seal as opposed to it still being in the truck( or blazer in your case) I know it sucks when stuff like this happens. A few years ago When I was putting the 350 back into my 3100 I got it all together, filled it with antifreeze only to find that one of the rear freeze plugs was cracked. Yep, pull the transfer case and and tranny replace the plug and so forth. The plug had bounced off a bolt or stud when installing the engine and I didn’t notice. I check those types of things now
