No Crank No Start After Transmission Swap?

  • 3.0L
  • V6
  • 4WD
  • 270,000 MILES
So, I swapped out a used automatic transmission on my vehicle listed above, automatic, 4x4, SR5, 6v, 3.0, with the hopes of keeping it from getting towed. It is in my buddy’s shop still. We kind of messed up by removing the wrong bolts on the starter and put it back together after it came apart.

It seemed to be fine, but after the tranny swap the starter wouldn’t engage.

1. We replaced the starter, and it still will not engage.

2. I took off the shifter link to see if it was not in park due to improper
install, but no matter where I put the shifter it still will not engage
the starter.

3. I have radio, window and lock action, the dash lights up bright and the
battery tests full.

4. On the starter wires I have continuity between the two connecting

5. All the wires seem to be connected, functional, and the battery is well

6. I have not tested the alternator, but everything worked fine before the
tranny swap.

I don’t know much about transmissions, which is why I took this leap of faith. So, does this troubleshooting process lead me to a sensor that is not working in the transmission? Is it the shift position sensor? What other sensors would cause this problem? Did I miss anything but the alternator in my diagnosis leading of to the transmission? Everything worked fine before, and the starter was replaced, so if the transmission swap changed that then must it be the transmission? Please help.
Do you
have the same problem?
Tuesday, March 14th, 2023 AT 7:43 PM

1 Reply


I attached the starter circuit wiring schematic below, so you have a reference.

Here is what I need you to do. In relay box 2 (engine compartment) check to see if the alternator fuse is getting power or if it has failed.

Here is a link you may find helpful:

If it is good and has power, check the AM1 fuse the same way (confirming there is power present).

If all tests good, remove the starter relay from the same box and switch it with a different one having the same part number. If there isn't one, here is a link that explains how to test a relay:

If that tests good, have a helper turn the key to the start position while you check the black wire with a white tracer at the neutral safety switch for power. If it's good, confirm there is power out via the black wire with a yellow tracer.

If that checks good, go to the starter motor. The heavy gauge black wire should have B+ at all times. Confirm that for me. If it does, we need to check the lighter gauge black wire with a yellow tracer. This wire should only have power when the key is in the start position, so you will need a helper for this as well.

If you have questions, let me know. Also, let me know what you find or if I can help in any way.

Take care,


See pics below. Note: In pic 3, I highlighted the main FL. That is the fusible link and is at the battery. If this fails, nothing electrical will work.
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Tuesday, March 14th, 2023 AT 9:28 PM

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