Hi AVB,
To me it looks as though the transmission has to be dropped so you can reach up between the battery box and the outside frame paneling. I'm tempted to hand it back to the customer to see how long the belt lasts in its current state. If I adjust the tensioner further back the pulley is going to hit the RH brake mount. So any more adjustments will require a shorter belt.
I find the same problem working on more modern cars and even tractors. So much has to be removed to get to the part you need to replace. For example, some cars require the engine mount and bracket to be removed to change the fan belt! This means a 15 minute job turns out to be a 3 hour job.
