After 125,xxx miles I am going to go though the tranny. Any ideas on a good setup? Would rather buy a rebuild kit, and have it put in locally.

 

Go to https://www.pro-built.net/index.cfm?...t&productid=48 check out what comes in this kit, it should be more than enough in most cases. I would add the GM HD sunshell to this, as for the reverse input drum and low/reverse planet, only if they are questionable and need to be replaced. Do not cut corners, as you will pay in the end.

 

Minor note: I need it for 4L6O and what is the difference between HD and Street/Strip?

 

The Street/Strip 700R4 will allow you to shift the gears or leave it in drive or overdrive for full automatic upshifts. It has a cleaner 3-2 downshift & a better 2-3 upshift mainly because of the Trans-Go Performance Shift kit & Hi-Rev springs. The S/S uses Kolene steels in the 3-4 clutch pack. It can handle up to about 550 horsepower (HD 475-500 horsepower max) safely as long as you use a 10" or smaller diameter torque converter.