That's Automatic Transmission Fluid and not the regular oily  types you may associate with ( b(atf)e)    but I believe the level of customer service comes out to about the same. Ok maybe Isuzu won't shoot you for not buying their cars, since there would be a load of  bodies littering the highways in AZ ,but  given the way they  set up their  transmission  servicing I think it's not that they have decided not to  , just they've not had the chance.

Justification

We have a 99  Rodeo ( also known as a Honda Passport) which has a GM "inspired"   automatic transmission.    Even if you don't do any work on your vehicle you probably know that there's many specialized fluids that need to be monitored to keep you shifting , steering and  seeing  ( washer fluid for those slow folks)    Not asking you to change anything, just take a look  and then take it to the shop if it needs more.   So you can see the brake, steering and water pretty easily, oil via dipstick and  in most cases the same applies to the transmission.  

Unless you are  a southern belle and have never pumped gas ,( oh they exist ) read on.

Here's how you check a rodeo. 

Start it up,  let it run a bit, ensure you are on level ground and then  get under the car,  there's no dipstick, there's no viewer,  Oh no we have to loosen the overflow bolt and then  see if anything comes out. If not  then to fill  we have to   pump in  new atf until it's level with the hole.  Ah and do this while the engine is running above you.   That's a part that's in their manual to inspect every  few thousand miles  it's an act of hostility on par with the sparkplug removal on some  80's Honda bikes.

This is about unfriendly a tranny to service as you can meet without attending a Rocky Horror show and telling them their Frank impersonation was out of sync and about as convincing  as Bob the Builder in the role, I digress.

So is this a smart engineering choice  to increase reliability  ,  e.g  stop  people overfilling or sticking in the wrong fluid and causing hideously expensive damage,  OR  a way to  keep dealers happy?    I know  that it's not making me happy and   the only happy bit about the story is that should you want to buy an Isuzu  made SUV today  you are going to get a Chevy Envoy , or Colorado pick up with slight style changes .