Hey Hooter, I can’t seem to find anywhere in this thread or any thread you’ve been in what engine you’re running. Small block or big block? How much power are you producing? Rear ratio? Posi, hooking good?
The 700/4L60 transmissions really aren’t all that strong. Good torque and traction and you’ll break it.
It’s easy to upgrade to the 4L65E level, it replaces the input and output gear set with five pinion gears. There’s also hardened input/output shafts, thicker clutch housings, more clutch packs, etc. Even better sprags and stuff in the converter. Plenty to do BUT it’ll be costly. When it comes to transmissions, you get what you pay for. A fully beefed up unit will cost beyond $4,000.00.
OR you could go one better, get a brand new GM 4L85-E. They can be had from http://www.crateenginedepot.com/store/Transmission-Assembly-4L85-E-2WD-24227618-P834C0.aspx This baby's got the five pinion gearsets also making it better than the TH400 or 4L80-E.
OH yeah, go get your money back from those guys who sold you on their poor workmanship.