Frank - I'm relatively new to this forum. 1985 300TDT wagon (California) Same problem - upshifts to fourth before 20 mph. Had fluid, filter, modulator, changed. Valve body removed and checked. Bowden cable is ok. Was told that it could be governor. Did not check vacuum yet. Have you figured out your problem, fixed it yet? Was told that rebuild would be way to go if I drop trans to check and/or fix governor.