If the transmission was recently removed/reinstalled to replace the B3 friction discs, the bowden cable/upshift delay actuator would also have been disconnected/reconnected. If during that process the adjustment was altered, that would have an effect on your shift points. This is fairly easy to fiddle with, might be worth a try before committing to a transmission swap. Another possibility is that the upshift actuator on the transmission end of the cable is not properly installed. There is a hook that must engage a bellcrank on the inside of the transmission case. It is possible to install the actuator without properly engaging the hook. (ask me how I know this......) Also, the actuator receives a vacuum signal to delay upshift on a cold start. A defect in this part of the system might also cause adverse shifting......

You can test to see if the hook is engaged by removing the cable at the throttle actuator end. Pull slightly on the cable, if it "springs back" the hook is engaged.....

I attached a picture of what this bowden cable/upshift delay actuator looks like.

Keep in mind that I am just a hobbiest mechanic........

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles