Transmission not working properly after swapping a 4.3l engine to a 5.3l engine?

1998 CHEVROLET SILVERADO
195,000 MILES • 5.3L • V8 • 2WD • AUTOMATIC
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STEVENHHH
  • MEMBER
  • 1 POST
I swapped engines from the 4.3l v6 to the 5.3l v8 and used the transmission from the v6 and torque converter. I got a new wiring harness, changed steering column, PCM and BCM, it will not go into gear, cranks and runs fine.
Jul 20, 2022 at 7:23 AM
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STRAILER
  • ✓Experienced Mechanic
  • 55,273 POSTS
Nice work, the first thing I would do is check the transmission fluid level, also was the torque converter completely installed (three steps) if not it has ruined the front pump of the transmission. here is a video to show you what I am talking about:

https://youtu.be/ZC7xHVMKLRw

Also, we should run the codes to see what comes up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Let us know what happens and please upload pictures or videos of the problem.
Jul 21, 2022 at 4:46 AM
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