Radiator hose transmission flush on old trans

My Volvo 240 transmission has been flushed every 30,000 miles through a hose you can connect to the radiator it's not really a power flush, I would say, but it's still a flush. It's time to do it again and I'm about to drive the car down three states so I figured I'd do it this weekend. However at what point is it safer to drop the pan and clean the filter instead of a flush as the car ages. It has 300k miles. Dropping the pan on these is a giant PITA. Researching it I've seen a lot of people saying you're fine with a radiator flush, while some would argue.

We generally recommend changing the filter every other fluid flush, before the flush is done. Especially on an older unknown trans, we'd rather find out that half of the clutch material is sitting in the bottom of the pan BEFORE wasting 13 quarts of fluid on a flush.

Ah, yea that's a good point. Fluid is expensive. Local shop wants $250 to drop and clean pan.

My shop used to charge $60 for a pan drop/filter. It was proportionally more if the filter was expensive or if it required a fancy fluid.

"flushes" are a crap shoot. If you have good, healthy clutches, flush away. After 60k miles, though, who knows if the clutches are great or on their last legs. Fresh fluid can dissolve things pretty quickly for the first 100 shifts or so. If you have 90% of your clutch material and a flush causes 2% more to scrub off, its worth it for the trade off of having all fresh fluid. If your clutches have 4% clutch material and you do a flush.... time for a tow truck.

I will only do pan/filter on my vehicles for that reason.

In reply to curtis73:

The company that made our flushing machine (T-Tech) has a warranty - if doing a flush wrecks a trans, they cover the repairs.

Haven't needed it yet I think the "changing fluid = wrecked trans" might have been true with purely-hydraulic transmissions, where the valve body was just plain worn out but varnish kept fluid going to where it needed to. Clean the varnish out, and you lose pressure to clutches and pistons, and you burn the trans out. Maybe.

Haven't encountered that problem yet, either.