I bought a rebuilt tranny off of Ebay last year for 925 out the door with auxillary cooler, rebuilt torque converter from Ronnie Smith Transmissions. 2 year, 24,000 mile warranty. installed myself in a gravel driveway (which was fun) and haven't had one lick of trouble with it. I have 10,000 miles on it and I got 2mpg better mileage and they use new rebuild kits from GM with updated parts, sunshell etc. AND! No core! They soak the price of a rebuildable case into price, so you can rebuild your own and sell or have as a back up or whatever.
It shifts like a dream and I have thrown a lot at it when driving.
2000 GMC Yukon SLE 2wd
5.3 4L60E
157,000+ on the clock.
They told me that the 4L60E's already have the vette server in them and the tranny you get is basically a 4L65E in a 4L60E case.....
Look em up. The price may be higher but at the time, it was great and they dyno every tranny they rebuild.
Ronnie Smith Transmissions.