I have an 86 f250 6.9 t19 4x4
i have a zf from a 90 f350 dually 2x4 7.3idi
I know the guts stick to tailshaft housing, will any tailshaft housing work? i dont haul much so would ether gear ratio work? will gas job guts/tailshaft housing go in my 2x4 bellhousing? I know i need the smf conversion (ebay $480) HELP!

 

You would need a ZF 4x4 rear housing. The main shaft end play has to be measured, and a shim added behind the front case input shaft bearing race to pre-load the main shaft pocket bearing and rear case caged needle bearings. I read that it was possible, but a lot of work, and not for a novice mechanic. Small parts kit and seal kit needed, should consider full rebuild while it's open. You would probably be time and money ahead by selling your 2x4 ZF and buying a 4x4 one... especially since finding a 4x4 rear housing at a nice price won't be easy.

On a brighter note, you can use your 6.9's SMF. You just need to get the specific 1987 6.9L ZF pressure plate and clutch disc... and be prepared to deal with gear rollover noise. From what I've read Amsoil full synthetic 50 wt ATF for semi trucks is the best solution. Hope this helps. Here is a thread on how to rebuild a ZF, including how to measure the end play and select the right pre-load shim if you decide to go that route...
ZF5 (S5-47) Rebuild - FSB Forums

 

Gear ratios for the 6.9 T19 and 7.3 ZF should both be the narrow range (non-granny 1st) gear set. If for some reason you ended up with a wide ratio ZF with granny 1st, you should still be able to start out in 2nd as long as you have at least 4.10 axle gears. With 3.55's you might have to granny start every time which would be a little rough.

 

What exactly are you asking? I can't make a lot of sense of your post.

If you're looking to turn a 2wd ZF into a 4x4 ZF...?
The mainshaft (output shaft) are different. There is no tailshaft, I think you're thinking of the rear housing. So what you really need is a 4x4 rear housing, and a 4x4 mainshaft.

You're better off finding a 4x4 ZF. Or find one out of an F-superduty (F-450). They use a 4x4 ZF with a parking brake bolted on the rear where a transfer case goes.

 

I have the other way around, do you have the ZF for the 1990?

anyway my question is I just bought a 86 ATS turbo IDI 4x4 that the engine is 124 k miles and great shape from a friend who bought it from father in law original owner 20 years ago. This engine starts fast on one battery. The body and interior are in horrible shape so got it cheap.

I own a 1990 ATS turbo IDI dually 2x4 ZF. That needs a new engine and clutch job. Can I use the single mass flywheel from the 6.9 and buy a clutch kit for a 6.9 to save me significant money on the ZF in ridding the dual mass flywheel? From above it looks like it, but do I have to shim too, i am keeping my ZF trans, so no shimming? and use the 87 clutch kit specifically?

Is it as easy as it sounds? If so is there one clutch kit that stands out from the rest?

And do I change rear engine seals while doing this and or more?

 

The shimming was if you are REBUILDING the ZF. AKA, splitting the case, replacing bearings. If you are swapping engines, and leaving the current transmission as is, you don't have to worry about any shimming.

I don't know too much about different brands for clutch kits, except the Luk SMF kit I put on my truck has been great. It reduced the pedal effort tremendously so the truck is comfortable to drive. The newer truck I bought supposedly has a Southbend SMF kit, and the pedal effort is horrendous, feels just as bad as I remember the DMF being. As I haven't torn it apart, I can't say for certain its a Southbend, but there's a very good chance it will be getting a Luk kit at some point in time before or shortly after I put it on the road.

You could change the rear main seal while you're in there, its not too bad too do. I'd recommend getting the Ford teflon seal that comes with a sleeve and the install tool if you decide to do it.

 

yes in the 1990 I am keeping the ZF transmission, and putting the 6.9 engine in. So I understand I do not need to shim. and will do the suggest engine seal. Thanks.

I just want to be crystal clear as I can not return parts easily, I have to get them from the USA 1000 miles away. I live in baja. I am taking the SMF from the 1986 4WD and putting it in the the 1990 ZF to rid myself of the DMF. And at the same time I am putting in a clutch rebuild kit you are suggesting( Luk). So is the only thing I need to buy is a 1986 Luk 11" clutch kit 07026 and I am done with parts? I assume it is a 11 inch not the upgrade 12 inch? Or can i use the 12 inch one without doing anything else.

from rock auto:
LUK Part # 07026
4 speed trans.; equipped with Solid Flywheel
LUK Part # 07065
4 speed trans.; equipped with Solid Flywheel, 12" Clutch Upgrade