My boss has a 1996 7.3L diesel F350 5speed manual dumptruck and the transmission crapped out on us, it has the less commonly found ZF transmission that's all I know.
I am wondering if a 1989 7.3L Diesel F450 5speed manual transmission also a (ZF variant I how ever don't know which ZF it has). I'm more of wondering if it's possible to swap between those two years.

My boss has called a couple of his mechanic friends as well as a local junkyard, and they've all said it can't be swapped and say it has to be one from 1991-1997.

I've however have been reading different on the internet that either ZF 5spd manual transmission doesn't matter the year is able to be swapped. Hopefully someone can give me some insight.


This is the plate off of the 1989 transmission

These have been the only markings I've found on the 1996 transmission

1996

1996

 

Can it not be rebuilt? Even if you find one, it probably has potential to be worse than the one you have. Sorry I can't help with the 89 question.

 

It'll cost more then the truck is worth, sycro is ****ed, pins are none existent for 2nd & 3rd had to hold the shifter in, 3rd & 4th where grinding really bad, occasionally youd have to skip 3rd all together because it wouldn't go in no matter what you'd do.1st didn't exist for atleast a year and a half now. Currently the shifter is in Neutral but the fork is stuck in either 4th or 5th.

 

Also the 1989 F450 that has this other transmission in ik it was a solid tranny back when it had been parked, the owner could no longer work construction because of a injury. However worst case scenario in order to get the F450 running again it needs new injectors, bc somewhere it's leaking nd letting air in, and the bottom of the cab & rockers will have to get patched. Idk is it even worth the fight to pull the transmission and put it in the other truck if it's swappable or is getting the other truck running more worth my time?

 

Split the case on the 96 and find out what actually failed, not what you think failed. I rebuilt mine, so I can point you along the way.

96 has stronger case and better gear ratios (especially reverse) plus I am with the other guy... installing an undocumented, used trans that is over 30 years old from an F-superduty is foolish at best.

Those trucks were built to work and work hard.

 

I am just not of fan of my labor being wasted. You may think that other tranny is fine, but it might not be. That means you have to swap again. Maybe both, try to diagnose the 450, and tear into the tranny on the 96. Who knows, you might end up with 2 decent trucks for less work. But at least you will know where you stand.

 

Whoever told you it can't be swapped is both wrong and possibly kinda right. The bell is the same pattern, the input shaft has the same dimensions, cluch slave cylinders are in the same place and so are the shifter towers, so the IDI and PSD transmissions should physically interchange.

But the F-Superduty transmissions are actually 4x4 transmissions with a driveline brake bolted on the tail flange instead of a transfer case - if that F350 is a 2wd truck you'll have to use the F-Superduty AND its driveline brake setup (you don't need to hook up the brake cable etc) which is altogether much longer than a 2wd ZF and so the F350 will need the its driveshaft shortened and the front U-joint replaced with a 1350-1410 conversion one.

If the F350 is a 4x4 truck then the F-Superduty trans is a direct swap, you don't need the driveline brake as you're using the 350 transfer case in its place.

Gears will be a bit different, the early ZFs have a very steep reverse gear which kinda sucks in a 2wd truck, if it's a 4x4 then you just low-range the t-case while backing up and life is good.

Case strength is whatever, if you drive like a Jamaican trucker you're more likely to break stuff than if you drive nice and gentle. Obviously there are exceptions, but generally it's driver activities that lead to catastrophic failures.

Unknown condition of the F-Superduty transmissions is the main concern I think - can be good or can be screwed and you won't know for sure till you pull it and wiggle the input shaft at least to check for bearings play/wear. You can however pop the PTO covers and take a peek at the gears and such, and obviously if the fluid that comes out looks like Wolverine's blood then clearly there's something odd going on there. But at the same rate transmission swaps on these trucks are fairly quick and easy jobs, so if the F-Superduty one looks alright inside visually it may be worth dropping it in the F350 and getting it back on the road and making money while its original trans is torn down and inspected and possibly rebuilt. Time is money, how much time can your boss afford to be without a truck? Alternatively can he recover the truck easily and cheaply if the "new" trans dies and leaves him on the side of the road with full load in the bed or trailer?

 

the main difference between the F-Superduty and F-350 trans besides the mentioned park brake is the 89 trans will be a ZF-42, and the 9 is a ZF-47. the 96 is a little stronger trans designed for 470 torque compared to the 89 420 torque rating.
and i don't know who told you the "less commonly found ZF trans" thing from, but they were wrong. i bet there were many more diesel trucks built with the ZF trans than with an automatic.