Look at the trans on the right 904
Then look at the overdrive trans on the left at how much longer it is than stock.
View attachment 1715721665
Being your overdrive trans is longer, you end up with a shorter driveshaft and in the process it steepens your driveline angles.
What is the tailshaft angle right now, car sitting level, and no shims at the tail shaft mount? 2° Negative ????
Now measure the rear pinion angle, what is that, 2° Positive ???
This is the senario you want with Negative degrees at the tail shaft and Positive degrees at the pinion shaft.
Raising and shimming the trans tail higher is going the wrong way, giving you too sharp of a driveshaft to tailshaft angle.
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Let's see what your angle degree measurements are to start with.
