Fuel economy for 89' IDI. (Transmission)

[TorchMadness]

I am currently running a 3 speed. What would my best swap be for fuel mileage?

 

[sjwelds]

ZF5

 

[riotwarrior]

I went from C6 3 sp to ZF 5sp...my rpm and speed changed immensly as did drivability...

 

[franklin2]

I also swapped from a c6 to a zf 5 speed. No other changes and I went from 12mpg to 15mpg. And It's so much quieter going down the interstate.

 

[Clb]

Add a brownie to that 5 gear, get more versatility to boot.

 

[icanfixall]

Many of the suggestions are correct but changing your rear gear ratio is another good way to change what you want.

 

[riotwarrior]

He likely has 3.55 @icanfixall already so ....E4OD and its inherent headaches of a swap...or ZF 5SP swap or add an overdrive or brownie of some sorts....

 

[jwalterus]

just spring for a GV

or yank a 3.00 D44 rear from a '70 f-100

 

[TorchMadness]

I went from C6 3 sp to ZF 5sp...my rpm and speed changed immensly as did drivability...

What all did you need to change from the C6 3 speed transmission to the ZF5

 

[OLDBULL8]

About a $1000 dollars. Clutch, flywheel, ZF4 or 5, drive line shafts, brake clutch assembly, firewall mod. Someone else besides yourself, add another $800 to $1000. Then another $250 to $500 for Hydro brakes.

 

[riotwarrior]

F 250 or f 350 2 wd 4wd what?

 

[TorchMadness]

F 250 or f 350 2 wd 4wd what?

1989 F250 7.3IDI 4x2

 

[TorchMadness]

I went from C6 3 sp to ZF 5sp...my rpm and speed changed immensly as did drivability...

Would you happen to have a full swap parts list and brands my ZF5 arrives wednesday

 

[riotwarrior]

Would you happen to have a full swap parts list and brands my ZF5 arrives wednesday

Pretty straight forward....

Trans tunnel cover and shifter boots

Pedal assembly for std trams

Clutch master slave and line...year appropriate

New plug for std trams to use back up lights...

Std F350 zf crossmember a d brace

If u had a c6 likely drive shafts same length

Since a brick nose @freebird01 firewall brace so no problemo later on.

Std column if so inclined.

New pilot n throwout bearings

New.clutch and pp and flywheel.

I used all my own parts so no numbers sorry. I have a lot of used stock here.

 

[catbird7]

What year is the ZF? I think 1992 and up didn't use a speedo cable rather a sensor on the rear axle. Your 89 truck has a cable. Possibly the ZF (if newer than 91) can be adapted for the cable??? Someone on here will likely know........