Doesn't the TC fluid circulate round through the tranny oil cooler etc?

 

That's really interesting because I've done this 3 times now on three different cars and that's definitely not what I was told by the guys operating the BG flushing machines. Level 10 transmissions in Hamburg NJ did my Q45 several years ago and they used their own set-up. I had the same impression from them. I mean that was whole point of using one of those machines.

Here's a description of one of the machines from their website:

BG Big Dawg®
High Capacity Power Flush and Fluid Exchange SystemJust like its predecessor (BG PF20), the BG PF20-500 Big Dawg® High Capacity Power Flush and Fluid Exchange System is the ultimate solution to effective automatic transmission maintenance. It’s built tough for large vehicle transmissions and handles small vehicles in a snap. The BG Big Dawg® cleans all internal transmission components including torque converter, valve body assemblies, lines and cooler vanes. Then it thoroughly flushes the old fluid and cleaner and simultaneously installs new fluid. It can easily handle the exchange of 14 gallons of ATF at 280 PSI IN LESS THAN ONE MINUTE!

The PF20-500WO is sold without fittings; both light duty and heavy duty fittings are available individually or in complete kits.Part No. PF20-500WO


Bob S.