I have 1974 Jacobsen Gt-14 garden tractor (Same as Ford Lgt-145), It originally had a 14hp Kohler K321, but because of the broken rod, I re-powered it with a 12hp Kohler K241. I flushed out the filter and replaced the transmission fluid and it still makes an awful whining noise, especially when going up hill, in reverse or pulling a cart. Going down hill or on a level surface it evens out slightly and sometimes goes away completely. It seems to go normal speed. I dumped a gallon of the fluid in but I have a slow leak by the hydraulic cylinder so It is about 1/4" low. My main question is, can this be fixed or is the tranny shot? I towed it (in gear) for a short distance, could that hurt it? I also shifted from high to low while driving a few times, but I learned that that's not good though it didn't effect it, at least not enough that I noticed. Could it be normal? Did the repower effect it any? Any help is appreciated, I want to put this machine to work. Thanks