I started on some modifications on my unit today. This is basically to change the lower section of my 06 unit to be like the older 04 unit.
Here's what the 06 unit looks like with the lower bushing removed. Man, those 3 channels are quite big. They travel up and come out right above the top of the bushing. One thing though, they were bone dry, and my unit has 60k miles.
Here is a shot comparing the 04 and 06 lower bushings. The 06 is about a quarter inch longer
The lower bushing was wasted. And the wear was very uneven. On the bottom where it meets the gear, it was out two and a half thousandths and eggshaped. On the top, the wear was a little less-it was out about a thousandth.
On the shaft, on the area where it meets the bottom bushing, the scoring went in about a thousandth and a half. At the top bushing area, the scoring barely went in-about half a thousandth. Here is a shot of the shaft repaired, all welded up and polished. Just like new. This is the same shaft as the one from the bottom picture (the shaft without the groove)
Here's the weird part. The top bushing in the unit was ok. We mic'd the bushing top, middle, and bottom, and it looked good. So I'm going to re-use it.
This weekend, we're going to cut the flat spot and drill the hole in the unit lower. We also need to fab up a new lower bushing which will be the same length as the 04 bushing. The one thing that I will change from the 04 design is that I will groove the lower bushing instead of grooving the shaft. The machinist thinks that this is the better move, and should be more efficient.
I'll post more pics as I finish up.