as long as you remember to unlock it when you come to a stop, there shouldnt be any issues. it may improve acceleration a slight amount as well as a firmer shift at low speeds. the factory stall on the convertor is 1800. it will also reduce trans temps, which is always a good thing

 

If you have a well modified engine, locking it under acceleration could benefit you. I have a hydraulic lock up kit installed, and I HATE IT! The TCC catches on top of 3rd gear, I was told it would come in on top of OD, and by placing the shifter in 3rd I would be able to lock it out. From a dig, she screams like a bat out of hell, slams into second and breaks the tires loose, hits third, jumps forward, then bogs down when the torque converter locks. 65-85 is a DEAD spot. If I let it hit 6 grand before I shift into third, it seems to help because once it the TCC locks, it's in the power band. If I shift while in the power band (about 4500 RPM), it bogs terribly.

What I've noticed, is this hydraulic lock up seems to be tough on things at lower speeds. It kicks in at about 35, but sometimes it won't disengage until 20 mph. It seems to be tough on the drive line (U joints, rear end, ect.) and also bogs the engine down at slow speeds.