Options for overdrive

[palmtree]

My car needs to lower it's highway RPMs. Is the easiest fix to swap in a tranny with overdrive. It now has the stock 3 speed auto. The car is a 1980 265 D24.
Thanks

[Jason]

A M46 or M47 would be the easiest manual trans options.. The ZF22 that was in the turbo diesel wont work since the bellhousing will have the wrong angle. I'm not very familiar with the later D24 2xx series cars, but I thought they had a 4 speed auto. I could be wrong though.

Jason