[Lanemac]

I just recently purchased a 89 f-350 7.3 2wd crew cab dually, it has the c6 transmission and 4:10 gears in the back. I got this pickup for 1600 which I think is more than fair considering it only has around 120xxx miles.

When I'm driving down the highway at 55 the truck runs around 2500rpm and about 2700+ at 65. I hear the c6 is a good transmission and is good for towing, which I will be pulling a horse trailer in the summer time, but I don't like driving with my truck wound up so high just driving down the road. I've looked into an aux overdrive unit but not looking to spend quite that much just yet. If I pick up a cheap zf5 or 6 how hard of a swap would it be and what would my rpms be at crushing speed? And will I loose my towing capability if I swap?

Thanks

 

[tjctransport]

a zf will drop cruising RPM's around 500 RPM at 55MPH.
my 88 7.3 with C6 and 410 gears will do 80 MPH at 3300 RPM governor shut off..

 

[aussamdad]

maybe re-gear the rear end instead.