T56 Magnum - Front plate possibly not straight?

[Zachalanche]

Hi all,
Once again, I'm hoping to tap the knowledge of someone who knows more than me.... which covers 99% of you.

I'm in the process of shimming my throw out bearing for a new clutch (switching from a single to twin disc). When I measure from the throw out bearing to the front plate of the transmission (where the bellhousing mounts), I get quite a bit of variation in my measurements, and they are consistently lower on the upper passenger side and consistently higher on the lower driver side.

I must admit, that using calipers and a straight edge (piece of square aluminum tube) against a bearing that does allow for some small movement is not going to produce the most repeatable results, but the measurement on one side is always around .050 larger. Out of curiosity I rotated the throw-out bearing snout 180* just to see if it wasn't straight, but the measurements did not flip, so that doesn't seem to be the cause. I also put a dial indicator on the throw-out bearing to see if there was a high side, but to my surprise it only had about .001" of runout.



It seems to me that there might be a dimensional issue with the front plate of the transmission, and 0.050" would create a massive misalignment (I think). this would be enough to make the average bellhousing mis-alignment insignificant. I would also expect this to impact functionality. However, years ago when I first installed this transmission I only measured in one spot when I shimmed the throw-out bearing, and I guess ignorance is bliss, because the transmission has not had any issues shifting in any of the gears.

So, maybe I am crazy, maybe my tools or my methods are to blame, or maybe there is something I should be concerned about. Which is it? what would you check next? I don't want to get into having my bellhousing or transmission machined to make everything perfect just for the sake of making it perfect........ unless there truly is a problem here.