ok so im scared to upgrade my truck performance wise because of the stock tranny' the thing is tho is i don't have enough for a built tranny...so i was thinking about putting a shift kit in...how secure in the tranny could i be? Right now its just a stock 5.3 reg cab. What kit would y'all recommend

 

Transgo HD2 is what most guys are running in their stock transmissions. I have one on order right now. Combined with a Trucool 40K transmission cooler...should help extend the life of the trans.

 

Unless you are doing a cam, headers, tune, nitrous, big tires with stock gears, etc...the tranny will be ok. There is Torque Management to help save the life of it.

In all honesty a shift kit may be hurtful on stock trans. You are putting more shifting force to the stock clutches, stock bands, and the extremely weak Sunshell Gear.

As above, a bigger cooler will help save the life of it along with proper fluid level. Too much fluid is bad for a trans.