Im in the process of putting a zetec into my mk4 escort estate and i was going to use a mk4 escort xr3i gearbox for it but after taking the 4 speed box out i was wondering if it would make any differance if i took the diff out the 4 speeder and put it in my 3i box ? Ive got my 3i box in bits any way rebuilding it so it will just be a case of taking it out the other box and slotting it in.
cheers mark.

 

Do you wan't to exchange the diff or the final drive ratio? The diffs are the same and the final drive ratio is the ratio of diff crown wheel teeth count divided by the mainshaft driving gear teeth count. If you want to change the ratio, you need to exchange the mainshaft and the crown wheel. The problem is that your other mainshaft is a 4speed one.

 

sounds like alot of agro i think ill just leave it as it is.

 

4 speed mainshaft will not go into 5 speed box as mentioned above , I think you will be better off with the 5th gear as it will be pulling a lot harder aswell , and would thingk the 2 diff ratios would not be that far apart anyways

 

it was just a thought good job i asked then and didnt just do it