yo Chris,
Please confirm that you have a 1990 Bronco; add engine. transmission type too and any major modifications.
pc by Chris A
E4OD have 20 pan bolts; P-R-N-D-2-1 shifter pattern
I see in your first post here you did post a 35 Code;
can you test for codes again, for at least KOEO?
The leak Most likely has nothing in common with the starting problem, but could cause the "floor it to move" due to low trans fluid level if reddish E4OD trans fluid is most likely the pump seal; check for rear main leak on engine as well
Read this & More by Ford for a 06 E4OD, but applicable to your 90;
Leakage at the front of the transmission as evidenced by fluid around the converter housing, may have several sources. By careful observation it is possible, in many instances, to pinpoint the source of the leak before removing the transmission from the vehicle. The paths that the fluid can take to reach the bottom of the converter housing are as shown in the following illustration. The following five steps correspond with the numbers in the illustration.
http://www.diesel-dave.com/vehic/manual/stj/stj71a22.htm#extract_1031
Was the replacement ECM from same year, same engine and same Calibration Code?
Read this by Ryan M
http://web.archive.org/web/20130409093505/http://oldfuelinjection.com/?p=17
And Diagnosis by Symptom Index @
http://www.diesel-dave.com/vehic/manual/stj/stj71a24.htm#extract_1037
Look @ Engagement Concerns
•No Forward Only
or
•No Forward and No Reverse Only
Can always check the connector pins to ECM for what Ford describes as "terminal back-out"
Read & See this by Ryan M
http://web.archive.org/web/20130506231607/http://oldfuelinjection.com/?p=74
Did you check all battery to frame, engine and firewall Grounds as well?
As well as those on radiator support and bother inner fenders?
Locations in a 90 from 90 Bronco EVTM; "...G100 LH side of Radiator support; G101 RH side of Radiator support; G102 RH side of Radiator support; G103 LH rear side of engine near knock sensor; G104 LH rear side of engine compartment, near electronic engine control (EEC) module, on the left fender close to the firewall; G105 LH Side of engine; G106 RH fender apron, near voltage regulator; G107 RH fender apron, at starter relay; G108 RH fender apron, at voltage regulator; G109 RH fender apron; G201 LH rear side of I/P (looking at the diagram it is at the bottom of the driver's side dash assembly. Screwed to the bottom edge, just to the left of the steering column. It is the ground for the instrument cluster); G202 Behind RH cowl panel; G203 RH rear side of radiator support; G204 On steering column; G205 Behind Center of I/P (Dash); near speed control amplifier; G400 LH side of cargo area; near rear light assembly; G401 Below LH side of cargo area; near crossmember; G500 Inside driver's door; near left door speaker"
Source: by BroncoJoe19 (Joe) at Ford Bronco Zone Forums