tgorbett

I just replaced the older style upper gearset with the newer style that has the thicker floors. The gearset came with a new set of needle bearing sleeves (races). These are the races that are pressed onto the bearing chimney in the drive shaft housing and top cover. The new races are actually shorter than the old ones and needed to be pressed on to the chimney further than flush with the top of the chimney. All of this according to Merc. Service Bulletin 2001-17. I realize that the gears have thicker floors, hence the need for thinner shims. What I don't understand is why the bearing races are shorter. The picture in the service bulletin shows a pre-1999 drive which is what I have (I believe this to be true) and a 2000 and beyond drive. It looks like Merc took the flat ridge off of the top of the chimney which essentially shortens the chimney, The bearings inside the gears must be shorter as well, yeah? Can someone shed some light on this?
Thanks a bunch.

Griswald

the new race will in fact press down past flush on the tower. if memory serves, this distance is about the new thickness of the gear floor. If you don't press the bearing al the way, the top cap will not seat

tgorbett

So can anyone confirm if the bearings are shorter in the new style gear?

Mr Gadgets

Yes.. the bearings in the old gears is a 3216 and the new ones are 3214's. There is about an 1/8" difference.
You can get the 3216's all day long, but getting your hands on the 3214's is difficult. Only place I know of is Imco. Merc has ownership of that bearing..
You also need to use the new cone clutch with those gears, fyi.

Hope that helps.
Dick