Rep Power: 265

A friend of mine just gave me an S40 with new koyo bearings, which he calls rebuilt. It doesn't grind, but it's difficult to put into gear sometimes. It's got loads of slack and a little backlash which is between the final drive and the countershaft. That's why I swapped transmissions, because my old one did the same thing. It feels like the transmission wants to bind when going down hill in gear because something in the transmission is shifting depending on how I drive, hard or soft. The harder I drive, the more normal the transmission feels.

Summary:
Hard shifting
Gear clashing
Excessive transmission slack
Some sort of bearing noise but the bearings are new. Could be differential, gear clash...

This seems to by a typical problem with these transmissions and I think it's caused by the driver putting too much strain on the trany over time such as not depressing the clutch over speed bumps, or not depressing it when a bunch of trany load will be anticipated.

So my question is, how do you fix that excessive slack present in all gears? Is it the open differential gears wearing down? Is it as simple as re-shimming the differential and mainshaft, or are the gears themselves worn? There must be a way to tighten it back to spec so that you can truly call it a rebuild.