I just spent $3969.28 on a 4t65e transmission rebuild for my daughter's 04 Lesabre with 182K on the odometer. This car has been in my (BITOG) care since purchased in 2010 with 27,152 miles on it. The engine burns/leaks nothing, the P/S turns like butter, the A/C and heat work well, numerous window regulator replacements, wheel bearings, brake pads, radiator, etc., but EVERYTHING
on that car functions. Yes, I know, the car is worth maybe $2500-$3000....But in today's market, it would take me in excess of $10K to REPLACE
the dependability I know and trust in this car, so the repair was worth it TO ME.
I also participate in a face book page for Lesabre fans https://www.facebook.com/groups/148514530744628
and I've seen odometer pictures of 3,4,5-600K on 3800 engines.
You may be in a similar situation.