Sorry to repeat: 4speed to zf5

KevSrFord · Feb 16, 2020

I haven't been on in awhile and can't find the thread explaining the 4 speed to zf5 swap. And search didn't show it either.
I'm getting a zf5 for my 85 f350 2wd 6.9l.
I know the transmission is a direct bolt in but do I need to switch drivelines as well or will my driveline work?
Also should I step up to the heavier clutch? I am doing the clutch while I have transmission out anyway.
I am loving my truck. The thing is a work horse. I hauled some gravel a few weeks ago (6 tons) and my truck, trailer, and load scaled out at 24000lbs and my truck didn't hardly know it had a load on it. Granted I only went about 12 miles that way but still not many trucks could handle that kind of thing.

IDIBRONCO · Feb 16, 2020

I'm not sure what you mean by heavier clutch, but the clutch disc for the 4 speed won't work with a ZF5. The input splines for the ZF5 are bigger in diameter than the ones for the 4 speeds are.

Randy Bush · Feb 16, 2020

You will have to change drivelines, have one build the right length and mounting. Clutch ZF 5 clutch pack.

KevSrFord · Feb 16, 2020

IDIBRONCO said:
I'm not sure what you mean by heavier clutch, but the clutch disc for the 4 speed won't work with a ZF5. The input splines for the ZF5 are bigger in diameter than the ones for the 4 speeds are.

basically I was talking about 11" vs. 12" clutch. I believe the 12" is considered heavier.

IDIBRONCO · Feb 16, 2020

It's up to you, but this would be the time to do it if you want the bigger clutch.

KevSrFord · Feb 16, 2020

Randy Bush said:
You will have to change drivelines, have one build the right length and mounting. Clutch ZF 5 clutch pack.

Can I just use the driveline that originally was with the zf5 as long as the wheel base is the same?
Sorry for all the questions. This is my daily driver and I want to try to have everything in place when I do the swap as to limit down time.

KevSrFord · Feb 16, 2020

Thanks also for the help. I got the transmission for $500 that is in good shape and is the only major modification I plan on doing to my truck. It only has 71000 original miles now and runs perfectly. I'm just wanting to step up the fuel mileage a bit even though it is doing real good as it is right now. I've never checked it with a load on it but I'm getting right at 18.5mpg as a daily driver as long as I keep my foot out of it.

Randy Bush · Feb 17, 2020

Yes I would get the ZF5 drive line if you can, but may still have to have it sized which is no big problem . Just have to get things together and take measurements, made sure the rear wheel are on the ground though.

KevSrFord · Feb 17, 2020

Randy Bush said:
Yes I would get the ZF5 drive line if you can, but may still have to have it sized which is no big problem . Just have to get things together and take measurements, made sure the rear wheel are on the ground though.

Thanks

Knuckledragger · Feb 17, 2020

Check the U joint sizes, some early have 1330 and later have 1350. There are double sized U joints available, but are sometimes special order.

I am getting ready to do this swap on an 87 4x4, but need to rebuild the ZF first. Got it for $150, but is a question mark. If anyone has a manual for them, I am very interested.

How about the flywheel? Double or single mass?

Randy Bush · Feb 18, 2020

http://www.vaglinks.com/Docs/Catalogues/ZF.com_S5-42_47__47M_Service_manual_.pdf Maybe this will help you. Also single mass flywheel setup.

KevSrFord · Feb 18, 2020

Knuckledragger said:
Check the U joint sizes, some early have 1330 and later have 1350. There are double sized U joints available, but are sometimes special order.

I am getting ready to do this swap on an 87 4x4, but need to rebuild the ZF first. Got it for $150, but is a question mark. If anyone has a manual for them, I am very interested.

How about the flywheel? Double or single mass?

My understanding is the single or double mass flywheel depends on springs on the clutch.
The clutch kit I planned on ordering I believe comes with a flywheel but I was going to verify that with the manufacturer before I ordered.

JAKRANCH · Feb 19, 2020

When I swapped my 85 the original driveline worked

IDIBRONCO · Feb 19, 2020

It did in both of my 1985s too.

KevSrFord · Feb 19, 2020

JAKRANCH said:
When I swapped my 85 the original driveline worked

Thanks. I will get some good measurements when I pick up the transmission on Tuesday.

Randy Bush · Feb 19, 2020

KevSrFord said:
Thanks. I will get some good measurements when I pick up the transmission on Tuesday.

Other then doing a side by side comparison of the drive lines, just make sure the rear end is sitting on the ground if measuring for the drivelines in the truck, makes a big difference.

Sorry to repeat: 4speed to zf5

KevSrFord

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IDIBRONCO

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Randy Bush

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IDIBRONCO

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Knuckledragger

blowing chunks and grabbing porcelain

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IDIBRONCO

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