Auto transmission specs??
 

Where can I find the gear ratio specs for comparison between a 1984 190D auto trans and a 1988 190E auto trans?

Well it's me again PJ. Transmission gear differences will be very minor if any. I know you will be able to live with either trans if you can get it to fit. It might well be that the rear axle ratio shows a greater difference, and probably not much there either. But that is where the difference would show up.

The transes might have different setups in the valve body for different shift points, but the gear ratios are the same. The difference in gearing is done with the rear end.

-J