I am looking at a 1985 F350 4x4 Diesel. Which manual transmission came out in this truck? How much work would it be to convert it to a ZF5? Is the ZF5 even an improvement over the original 4 speed? Any and all input welcome!

 

with the 6.9 Diesel, i believe all f250/f350 came with the Borg Warner T19, its synchronized in all 4 forward gears, very smooth shifting and strong. It depends on when and where you drive this truck. if its mostly off road, or at city driving speeds you probably dont need an overdrive gear. A good friend of mine owned an 86 F250 4x4 with the 6.9 and T19, and it drove great. had enough power, and with 3.54 gears, it had plenty of top end speed. An F350 just might have lower axle gears, maybe 4.10's, and then the OD might be really nice, especially if your gonna be spending a lot of time on freeways

 

Yes, the 460's and the diesels came with the t19. A lot of the f250/350's did come with 4.10's less with the 3.54. I swapped to the zf5 in my truck and it's great. Even with a 4 inch lift and 35 inch tires, I still get 15mpg. I have the 4.10's.

 

I don't know that the OD (5th gear) would run at any lower o a RPM than the T19 Borg Warner. I have a 94FF350 4x4 with the ZF5. It is a Piweestroke. In 5thgear, with a ZF5 Tranny, I am taching 2000 rpm's at 56 mph.

 

*** Powerstroke not Piweesyroke. Sorry

 

The truck I am looking at has the C6. If I get this 85 F350 I am definitely doing a manual transmission swap. Will a 460 Donor truck work just as well as a 6.9L Donor truck then? Thanks.

 

T19 in 4th gear is 1 to 1. The engine turns 1 turn, the output of the tranny turns 1 turn. The zf in 5th is something like .76 to 1. The engine turns .76 turns, the output of the tranny turns 1 turn. It usually drops the rpms of the engine down 400-500rpm. It makes the drive much quieter, and really saves fuel. I gained 3mpg when I swapped mine in.

 

The 460 bell pattern is different than a diesel.
The ZF5 gearbox has an integral bellhousing just like the automatic.

Also, the diesel and 460 have different first/second ratios, because the diesel is torquier.

 

Sounds reasonable. So my donor truck will need to be a 83-86 F250- F350 4x4 with a 6.9 for the manual transmission conversion. ....

 

And if you want a Zf 5 spd, rather than a BW T-19 4 spd, you will need to find an 87 or 88 or newer, they didnt offer the 5 spd in 83-86.........

 

And, as stated the t19 behind a 6.9 had a slightly higher first gear ratio than the one behind a 460........As i recall, the diesel t19 was sort of a close ratio box, while the 460 was more of a true "granny" gear

 

Will a 2wd donor truck get the job done or will it need to be 4x4?

 

It was only the 4x4 460's that got the 6.32:1 first.

 

T-19's came either way, but you need to get a 4x4 gearbox if you want to bolt up the transfer case adapter.

 

I think it will be easiest finding a 83-86 6.9L 4x4 donor truck so I will have everything I need. After just rebuilding the ZF5 in my 94 I am definitely ok with going with the original Borg Warner for this 85. Those ZF Transmissions are costly!