to make your top speed faster ,you need to take out the idler shaft and put smaller sprokets on the input OR larger sproket on the output, do you run double fifty chain or something else ??? ,do NOT change the sprokets on the axles or you will have to do ALL of them to match, the only options you have to change sproket ratios is either the trani sprokets or the idler sprokets, i did the idlers on one of my 6x6s and it now does almost 50 clicks and that is nearly insanely fast, ive had many of the tranis apart from the early eighties to the late ninties and never seen a gearing difference but the tooth sizes were changed several times by the engineers trying to adress a weakness in the trani of all argos ,i believe that is why they have re-engineered the entire trani in the new ones , if you need more specific help in this let me know, i can calculate the sproket sizes for you, each tooth on a sproket decreases or increases the overall ground speed by a specific percentage ,but you need to watch chain clearences as well
He who has not cruised the back country in a 6x6 , has not lived life to it's fullest
A Mans level of mechanical education directly corresponds to the level pain suffered while getting it