2001 Ford Explorer Swap - Transmission Help

[mynameisjonas]

I have a customer's '74 Bronco that another shop did a 5.0 Explorer swap on that I am trying to troubleshoot a number of problems, but the biggest one the transmission. I was told the engine, trans, ecu, harness, exhaust, etc. was from a 2001 Explorer that was used for the swap. When you put the Bronco in gear it is like the computer is not getting any information from the transmission and the transmission is engaging and disengaging. In order for the Bronco to move you have to put your foot into it. I have not done this swap, but it seems like the transmission is missing a sensor input. It appears to be the factory Explorer ECU and harness. There is a speed sensor connected to the Dana 20, but that is going to the Dakota Digital cluster for speed input.

I have tried to find information specific to the transmission for this swap and what it might be missing, but I can't seem to find the info. Any help would be much appreciated.

 

[Broncobowsher]

Check fluid level. And condition since it sounds like it was run low and may be burning up from lack of oil.

 

[MD]

If the wiring looks original, it probably is a complete swap. The obd connector is possibly missing, but the codes will tell you if a sensor is bad, so the best place to start is letting the computer tell you what it thinks is wrong. Wiring the connector back in and connecting a scanner is your best bet to start diagnosis.
If the trans doesn't move until you give it throttle, it sound like the forward clutch is not fully engaging. The piston seals can be damaged from age or sitting. The drum can have tiny cracks which leak and the clutch can be worn (which is also caused by low pressure from the previous issues). By increasing rpm, you increase the fluid volume and the pressure to overcome the leak. So if the codes check out, I would check the pressure in the forward clutch circuit next.

 

[mynameisjonas]

If the wiring looks original, it probably is a complete swap. The obd connector is possibly missing, but the codes will tell you if a sensor is bad, so the best place to start is letting the computer tell you what it thinks is wrong. Wiring the connector back in and connecting a scanner is your best bet to start diagnosis.
If the trans doesn't move until you give it throttle, it sound like the forward clutch is not fully engaging. The piston seals can be damaged from age or sitting. The drum can have tiny cracks which leak and the clutch can be worn (which is also caused by low pressure from the previous issues). By increasing rpm, you increase the fluid volume and the pressure to overcome the leak. So if the codes check out, I would check the pressure in the forward clutch circuit next.

Thanks for the feedback!