From: Crawley, west sussex
clive, you are right that the additional transmission cooler is run in series with the stock engine coolant radiator, there are various schools of thought about doing it that way or just piping to the new cooler, I figure that GM think that their design is OK so I run mine in series.
Important points to remember are that you get the flow to and from the radiator/cooler/gearbox the right way around otherwise you get no benifit as the transfluid is the same temp as the engine coolant (which is what you are trying to cool down)
Mount the new trans cooler in a place where it will get maximum air flow, and make sure it is spaced away from the A/C condenser radiator by at least 1 inch, otherwise the air cannot pass thru the cooler itself.
Route the new hoses away from hot or sharp areas to aviod damage.
when finished, run the engine for about 15 mins before driving off, just to check for leaks as everything warms up, then take a test drive and check it all again when you get back.
when towing I found that it was better and easier to select D drive rather than OD overdrive, because in overdrive I noticed that the torque converter was locking and unlocking (hunting) and also that the gearbox was shifting between drive and overdrive at the slightest gradient or increase in speed, cruise helped, but all those uneccesary shifts just build heat and wear your box out.
using drive rather than overdrive returned about 17-18 mpg on a mixture of motorway and A roads.
Just a question to chevydancer, do later astrosafaris have engine oil coolers as standard?, new one on me if they do!
Former owner of "Lone Star" 93 Astro Tintop.
Now Van Less, but still love the hobby and the people in it.
CLEVERLY DISGUISED AS A RESPONSIBLE ADULT