Drive shaft length questions

Hey so here’s the deal I’m doing a e4od to Zf5 swap. Had it in mind d ever since I baught the truck but only recently was able to find an idi 4x4 in the junk yard. I have one week to get this job done. No biggie. Can do the swap in a day. Butttt. From my understanding I will have to have my drive shaft lengthened. And that will take 3 to four days for the guy to get around to doing it for me So my plan is to take the shaft off first thing and run it up to him. And then work on the rest of it in the mean time. My question is this. Can I simply take the length of my Zf5 and subtract it from the length of my e4od, and have him ad that much material to my shaft? Sounds logical but don’t know. My truck is a 1990 f250 extended cab long wheel base. Does anyone have an exact measurement of how long the shaft should be for the Zf5. Just to know it is a split shaft with a carrier bearing Kinda goes unsaid but I’ve read that it can very. Any info would be appreciated so I can know what to tell him and get it done as soon as possible. Thanks in advance

I would do the tranny install and then measure it for the driveshaft. You might have to move something during the install and that would mean your initial calculations would be off. "There is never time enough to do it right, but there is time to do it twice"

I went to Autozone and plugged in your truck. The front driveshaft for the E4OD is a Dorman 938-066. I did a google search on Dorman 938-066 and Dorman says this driveshaft is 40.5 inches long.

Went back to Autozone and selected the manual transmission front driveshaft. It is a Dorman 938-185. Dorman says this driveshaft is 38.875 inches.

They also sell some of the rear driveshaft parts also. How do you like those prices?

Man the prices of em new are terrible haha. I looked before that’s why I’m havin mine extended. I did get the front drive shaft from the donor truck. But it was a standard cab and somebody had cut the rear shaft so unfortunately getting the back shaft wasn’t an option.

DaveBen said:

There is never time enough to do it right, but there is time to do it twice"

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Sound advice. May end up doing it that way just for safe measure. Just curious if anyone who has done this swap on an extended cab had a measurement Meaby

Fwiw +1 on davebens post

My driveline guy has built probably 3 sets for my high articulation rock crawlers as well as modded several along the line.
His pearls of wisdom are...
At static ride height measure tween output and pinnion flange in 3 spots
Top middle bottom...
Measure full stuff and full droop ( on bumps) same way...
Leave 1" of compression travel stattic before it is collapsed...
Leave 2" engagement at full droop MINIMUM...
You dont need angle # onna road truck so we will leave em out...

I would think the donor front shaft would work. Once the swap is done you could have everything installed except the rear shaft. In all these parts, if you had a extra slip in yoke for the rear output of the transfer case, you could slip that in place and then just run around on the front end driveline with the truck in 4x4 till you got the rear shaft.

franklin2 said:

you could slip that in place and then just run around on the front end driveline with the truck in 4x4 till you got the rear shaft.

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Interesting idea. Hadn’t thaught of doing that. The trouble is. Is we sold our shop and have to be out by October 1. So can’t have my truck down waiting on the shaft. How far could I go on my front diff if I went pretty slow without doing any damage. Now I’m just kinda curious Could I go 8 or 9 miles without damaging the truck you reckon?

My local speed shop builds these axles from scratch for 375$ with a 2yr warranty. They suggest bringing the truck to their shop so they can measure the truck, build the shaft, and install it. Took about 20 minutes last time I did a E4OD to ZF5 swap.

You can drive on your front end for ever if the oil stays it it.

ISPKI said:

My local speed shop builds these axles from scratch for 375$ with a 2yr warranty. They suggest bringing the truck to their shop so they can measure the truck, build the shaft, and install it. Took about 20 minutes last time I did a E4OD to ZF5 swap.

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Do they do two piece shafts as well? I'll be needing one eventually. Dennys driveshaft only does single piece and I've heard bad things about our local fleetpride here.

typ4 said:

You can drive on your front end for ever if the oil stays it it.

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Yes, like he said you can drive with it normally, even going high speed down the highway. Only thing you have to worry about is that yoke that you stuff into the rear output of the transfer case working it's way out. Like he said, that is there just to keep the oil in it till you get the new rear driveshaft.

If you slide the rear yoke in all the way, and then have to take a rubber mallet and drive it a little more, it might stay in there by itself. Or possibly apply some thicker wheel bearing grease to the splines and stick it on there. The suction of the grease my help it not fall out.

You only get one chance to do it right the FIRST TIME...

It's possible to drive on just the front axle, it'll run the whole load and all. Ford actually did a joint effort with another company and made the Boaterhome, which was a bull noze van with a 460, ran on front wheel drive. Was a crazy contraption.

Till the slip yolk falls out.
Yes it will work, till it dont

There are plugs you can get that slips into the transmission output and keeps the oil contained by the original seal. 4-wheelers sometimes carry them in case the rear drive shaft breaks and they have to limp home on front wheel drive.

You could inert one of these, then still zip-tie a bag on top to prevent it slipping out while you drive: