My transmission is very much on its way out. 2nd and 3rd gear crunch if I shift fast, and the bearings are so loud that in 1st gear I hear more tranny than engine. Anyway...

I really want to install a urethane shift bushing set to clean up the shifting slop a bit, but will the harder bushings accelerate the death of the transmission? Or will it actually be better for it? I know the transmission needs to be replaced, but I can't afford it just yet. Any opinions? thanks