Sealed bearings inside a manual transmission?

[Headhunter38]

I'm in the process of tearing down my manual transmission from a 1987 4wd van. I noticed that both the input shaft and output shaft rear bearings are both sealed bearings. Apparently it's not completely uncommon as a Google search tells me that other people are asking about this for their transmissions. What I feel is more than coincidental is that both of these bearings are bad. The input shaft bearing I knew was bad because the transmission would whine in neutral and it would get quiet with the clutch depressed. I did not know the output shaft was bad until I took it apart.
My question is are these bearings supposed to be sealed by design or did someone use an incorrect bearing during a possible rebuild?
If this is by Toyota's design I'm thinking of replacing them without sealed bearings and or removing the seals from new ones. I can't see how a sealed bearing is any good inside a manual transmission. Especially considering the two that are sealed in this transmission are both bad.

[Jan-Willem]

I have no idea, but when I look up pictures of the original part numbers, some of the bearing do indeed look sealed, or at least shielded.
(toyota 90363-30059 and 90363-32024) so it might be original
https://toyota-usa.epc-data.com/van/yr22lg/2301/chassis/3305/33311A/

[Headhunter38]

Yeah I found in my research that they were originally sealed bearings. Well I cant see why on earth they would put sealed bearings inside a sloshbox oiled transmission. There would be no way possible for gear oil to lubricate them. The grease will not last long as evidenced by the only two bearings that showed significant slop were the two sealed bearings. I imagine that if they hadn't been sealed bearings that they wouldn't have worn out before everything else inside the transmission did either. Everything inside was in immaculate condition. The gears had no significant wear and the synchro were prestine. So with the new bearings I removed the inner seals on bolh of them. The seals facing the center of the transmission respectively to each bearing. Transmission shifts so smoothly now and is so quiet. It makes driving this van so enjoyable. BTW if anyone is looking to rebuild their transmission and is looking for a kit, this kit works for our transmissions https://ebay.us/m/qYHD2l. Its Transparts BK161.This is one without synchros, and I believe they have one with them as well. The kit is made of high quality nachi bearings and seals. It does not come with all of the correct paper gaskets though. I had to get some of them from the dealership. I will try find what ones it didn't come and update this thread later.