Replace tranny front (input) bearing?

If the bearing is noisy, then yes, but it takes either special tools and/or special techniques to change that bearing without taking the whole transmission apart. I would suggest changing the front seal for the transmission, but you have to careful not to move the input shaft to far so that you don't allow the needle bearings inside the input shaft to fall out.


Buy one of those "mainshaft repair sleeves" to have on hand?

Not a bad idea.



Is the original style seal felt? Ok to use that type(for 50k miles)?

Yes, they do work fine as long as the engine doesn't have a lot of blow by.



Is the rubber seal housing an upgrade like the cam cover?

Yes, Volvo started selling the rear kit, housing, seal and gasket as an upgrade a long time ago. FYI, it is not uncommon for the pan gasket to tear while replacing the rear housing. We use a patch to replace the missing gasket and oil resistant silicone like the "Right Stuff" to try to seal it up. However occasionally it still leaks so you might consider removing the engine to replace the entire pan gasket and possibly upgrade the front seal cover at the same time.


Anything else to consider? Have a new driveshaft.

I have seen more than one M40/M41 leak oil from the gasket(s) for the rear transmission bearing housing and/or O/D adapter front gasket. This is usually due to loose bolts. And when this happens the gasket(s) are almost always torn and in need of replacement. And to replace those gaskets requires the removal of the rear bearing housing which requires the removal of the rear bearing at the same time and that is a big job which has to be done without moving the mainshaft to far or it will also cause the needle bearings inside the back of the input shaft to fall out or to dislodge the front shift dogs and retaining spring.

If you are changing your clutch, make sure to change the pilot bearing and to get the flywheel properly surfaced with a step. See the picture below where you can clearly see the step. If you have an early B18 flywheel that doesn't have the locating pins, you may have to have the center opening machined to make room for the outer set of rivets on the clutch disc. These rivets will make contact with the flywheel about half way into its life. The result will usually make the clutch slip. This clearancing is already done on later B18 and all B20 flywheels which are all interchangeable. See the picture below.

And BTW, I usually stock all of the parts you will need including the front and rear crankshaft repair sleeves.





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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502