Engine Missing and causing hard shifts in Tranny on 2001 Silhouette

:banghead: My '01 Silhouette (137,000 miles) is in the shop as I type. I have been told that it is missing badly on 2 cylinders and this is causing the hard shifts in my tranny. It has been shifting hard in low gears and also in OD. What could cause the missing in the engine? Also, I am concerned that this will cause damage to my tranny. Should I consider replacing the tranny? I am willing to pay for this option in order to eleminate any future problems that may arise because of these "hard shifts". Is this a good plan, since I have read about so many problems with the tranny in this van?

do you have coil packs?

It is possible one of your coil packs have failed.

You have a 6 cylinder engine and therefore there are 3 coil packs. 1 coil packs runs 2 cylinders. This is a fairly easy fix and isnt too much money...

I would start with checking that and the plugs and plug wires....