1995 E320 Transmission stuck in 1st - no upshift

[eurosport]

I just had a shop install a used tranny from my other mechanic's 95 E320 sedan into the same year E320 wagon.

Had the shop that was doing the install replace the filter and filled it with Dex III (although generic brand).

Picked up the car today and it will not upshift (just stuck in 1st)

Any ideas? The mechanic that sold me the tranny said that I should do a hydraulic pressure test as maybe the shop did not position the TC correctly.

Any help would be appreciated - just drove it 4 miles (under 20 MPH) so I am hoping there was no damage done