Transmission swap for towing

Hi everyone, looking for advice. I've been using my 95 wagon to tow my race car around for the last year and a half. Coming back from my last race, it started slipping going uphill. I want to swap in something stronger.

Going back and forth on my options.

4L80 - affordable, should bolt up with repinned or reprogrammed ECM. Need deeper rear end gear. Late 90's/early 2000s 2wd van seems like a good swap candidate

T56 - should bolt up, common enough swap. Will definitely need gears (4.3+). Harder to find, but more fun

NV3500 - Truck transmission, shouldn't sweat towing. Less information available, probably look to dodge trucks for the wide ratios

Appreciate any input.

Thanks

Did you post on the facebook group a few days ago with this exact question? If so I'll skip reposting my response.