My 49 3/4T has the carrier bearing, so I would guess the 58 will as well. Behind the transmission will be a short drive shaft with its rear end held in a bearing mounted to a frame cross member. There will be a u-joint, then the longer drive shaft to the rear axle. If the bearing or its rubber mount is weal, it could cause jumpy starts, but I would think an oily or worn clutch is the more likely culprit.
The reason to check the bearing, it is easier to change than the clutch.
The bell housing pan comes off with a few slotted screws. There is a small hole drilled in the bottom of the pan to let it drain. If there is much dripping from there, you probably have a dirty clutch.

Current fleet (subject to change w/o notice)
\'49 GMC 3/4-Ton , 60 Austin Healey Frog-eye Sprite (some assembly required), 2011 Dodge Avenger, 2015 Jeep Cherokee. No, they don't all run.
My other ride is a (B737)no, (B767)no, A320.... Update... was Embraer E190, now Boeing B787.

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