Dave85zxt 0 #1 Posted April 28, 2009 Hi Guys, I just picked up an 8 speed transmission last night to replace my 4 speed. It has a much larger input pulley on it than my 4 speed. I have also noticed from pictures that tractors with 8 speed trannies have larger PTO pulleys on the engine. Can anyone tell me the recommended pulley ratio or the pulley diameter on the engine and transmission for an 8 speed setup? Thanks, Dave Share this post Link to post Share on other sites
kpinnc 14,587 #2 Posted April 28, 2009 Dave, the size of the tranny pulley should not be as important as the ratio between the tranny pulley and the engine drive pulley. You are correct the newer 8 speeds have larger pulleys, but they are used on tractors with larger pulleys on the engine as well. The early 8 speeds used the same size pulley as those used by 4 speeds, because the "high" range on the 8 speed is basically the same as the gearing in a 4 speed, and because it was still common to have a very small diameter pulley on the engine output shaft. Later, when the Wheel Horse PTO setup came out, the engine pulleys used were larger simply by the design of the PTO. In short, if you're using the 8 speed on a tractor with a small pulley in the front, the tranny should use the same diameter as what was on the 4 speed. If you go larger, you'll have much slower ground speed as a result. Kevin Share this post Link to post Share on other sites
Dave85zxt 0 #3 Posted April 28, 2009 Thanks for the info. I understand what your saying. Share this post Link to post Share on other sites
