717.4 transmission, the rear cover have original the 0,17mm gasket at both end and middle. The end is replaced with 0,25 and WIS says apply sealent on the surfaces, is it normal to apply sealent + gasket? And the reverse shaft locking bolt, do you need to remove it to get the middle section out?

For transmissions in general, this might be to increase end play or perhaps the surfaces are not smooth / flat so a gasket with more crush ability + sealer is needed.

Its machined cut these parts, i dont know seem strange to me. Dont see any other manual or people using sealent on gasket for this and do the gasket handle sealent stuff well? Original its thinner gasket and they didnt use sealent, lastet for 30 years.