Drive Shaft Length After 4 Inch Lift

[aiyana7.3]

So awhile back, I posted about some drive shaft problems I was having after lifting my 92 f250 regular cab 4 inches. The transfer case was leaking fluid, the u joints were shot, and the differential needed to be shimmed, after shimming the axle it still looked like this.

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After being told that the drive shaft is too short and needs to be extended, I took my truck down to a drive line specialist, they recommended I extend it by 2 1/2 inches. I had the drive shaft extended but now I cant get it back in the truck. I tried jacking the frame up in order to extend the suspension and get a little more distance between the diff and the transfer case but it still seems too long.
Here are some pictures of the drive shaft while the suspension is fully extended.

This is a picture after I took the transfer case seal out and pushed the shaft in until it was maxed out.

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Transfer case seal next to transfer case.

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This is where the drive shaft is lining up with the differential. Its a little hard to make out due to the tap I have on it to keep the U joint caps on but as you can see it still too long. The shaft wont go in any further than this.

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So is this drive shaft too long or is there something I am missing? If it is too long, how much should it be shortened?
Thanks again for everyone's help!

 

[Clb]

A general rule is flange to flange minus 1"
It looks like the shop "oopsed" I'm on my ifail and cannot see to well.
It looks by photo #1 ya needed 1-1 1/4" more, tae seal could be shot, or runnin on a rough spot now???

 

[aiyana7.3]

Ok, so i need to have that thing shortened by 1 ½"? Which would give it an overall inch extension?
Not sure what you mean by running on rough spot, but the transfer case seal and the bushing is new and nice and tight if thats help.

 

[Clb]

Dont quote me to the driveline shop!
Ask the where the problem lies and make em fix it.
Its not clear on my end and in no way could I set it up blind from here.
In order to add 2-3 inches the shop should have replaced the entire shaft using your yolks.
Hope this helps, I was trying to give you some idea of the process.
As for the seal, the metal surface tends to wear under the lip seal and reduce the tension of the seal allowing a leak.

 

[aiyana7.3]

Its not clear on my end and in no way could I set it up blind from here.

I figured that haha i was just trying to make sure it needs to be shortened by some amount.
Do you usually need to lengthen drive shafts after a 4 inch lift? I keep being told it isn't necessary until over 6 inches of lift.

 

[IDIoit]

is this a 2 piece or a 1 piece driveshaft?
if its a 1 piece, its too long.
if its a 2 piece, do you have the carrier bearings loose when trying to install?
is the intermediate slip yoke bottomed out?

my 89 frame has a 4" lift on it, and uses the stock front driveshaft.
the rear is the same length as my 87, but i relocated my rearend about 60" so it dont fit no more..lol
the truck ran with these in before i tore it down

 

[Clb]

Every job is different, the shop owner is your go to guy!
I had to do both on my yota , 3" lift, add doubler in rear lost 8" the front needed a couple inches added ( on same pickup points.
As idiot said.
Seriously whats the shop saying?
You spent cash make him earn it!
Or did joe schmoe do it for you?

 

[aiyana7.3]

Its a one piece shaft on a regular cab long bed. Everything is completely maxed out. Looks like its another drive to get the shaft cut again haha

Here's there deal with the shop. I took the truck down to a local drive line shop. we decided they were going to order a longer slip yoke instead of having the drive shaft extended and install it when they are replacing the u joints. When I took the truck down the next day, they told me that the only option was to lengthen the shaft. Because they weren't able to lengthen in it themselves, they would need to drive it down to the only place that can, (hour and half away) drop it off, and pick it up the next day. That means the truck would be sitting in the shop taking up too much space for too long. So they just couldn't do it. I asked the manager to at least tell me how much longer shaft needs to be. He told me 2 1/2 inches so I took the truck home, took out the shaft, and drove it down to get it lengthened. The manager did tell me the wrong amount but I didn't pay him anything so I doubt he is going to do anything about it. Worth a shot though haha
Its the repeating story of shops just not wanting to deal with this truck

 

[IDIoit]

the way i measure driveshaft lengths
is to install the slip yoke all the way.
clock both U-joints so that there the same on the slipyoke(not the one connected to the driveshaft) and the rearend.

measure from THE BACK (the rear part closest to the rearend) of the U-joint on the slipyoke.
then run the tape to the yoke on the rearend. so that it will clear the front of the yoke.
this will give you center to center U-joint measurement.

also, lengthening your driveshaft cannot be done without a new tube, or a longer driveshaft cut down to your specified length
i usually go to the junkyard, find the same u-joint measurements, then have it cut and welded while on a big ass lathe.
ive tried to do it myself, but without a lathe, its a pain in the ass.

 

[nj_m715]

I can't help you deal with the shops, but I can offer this advice. Make sure you get it sized correctly before running it. If you install a shaft thats too long and then hit a bump and bottom it out you'll be shopping for a new trans or transfer case.

 

[Black dawg]

how did you lift the rear, dont usually need to shim? Factory pinion angle on these trucks is usually 1.5 degrees lower than t case output angle (angles equal under heavy load). If you measure so that the shaft has 1.5 inches before it bottoms out, it is usually pretty safe.

 

[franklin2]

My 89 is a regular cab f250 with a 4 inch lift. The rear shaft is stock and has never gave me trouble. It was a c6 and now it's a zf, and when I used the rear driveshaft from the zf(it was about a inch shorter), it had larger u-joints, so I used the rear shaft out of the donor, same year truck, same wheelbase, and it worked fine also with the 4 inch lift.

The problem I have since I bought this truck is the front driveshaft. It has had a bad vibration all the time I have had it, and I have played with a longer shaft for it, and it also has a shim under the driver's side spring. I am still working/brainstorming on that whole situation though. I did make the front shaft 2 inches longer, and it did help with the spline engagement.

P.S. It just dawned on me, if you have a zf and you could find a driveshaft from a c6 equipped truck, that might give you what you want.

 

[Clb]

To the op.
I am being serious here!
You got screwed by someone who is not(NOT) a driveline shop!
Could be miscomunication??? But a long yolk is cutting corners'PERIOD!
As they do 't seem to be adle to ballance the setup you should take the drive line to the REAL driveline shop down the road.
The equipment is not in your regular machineshop nor midas type wrench!
My guy does a 24 hour turnaround, strips all the road grime and repaints them before you get it back!

 

[Clb]

To the op.
I am being serious here!
You got serviced by someone who is not(NOT) a driveline shop!
Could be miscomunication??? But a long yolk is cutting corners'PERIOD!
As they don't seem to be able to ballance the setup ,you should take the drive line to the REAL driveline shop down the road.
The equipment is not in your regular machineshop nor midas type wrench!
My guy does a 24 hour turnaround, strips all the road grime and repaints them before you get it back!
He only does differentials and shafts has the equipment to ballance to a gnats *** and knows how to use it!
I second the dont drive it till its right!
Fwiw

 

[aiyana7.3]

the way i measure driveshaft lengths
is to install the slip yoke all the way.
clock both U-joints so that there the same on the slipyoke(not the one connected to the driveshaft) and the rearend.

measure from THE BACK (the rear part closest to the rearend) of the U-joint on the slipyoke.
then run the tape to the yoke on the rearend. so that it will clear the front of the yoke.
this will give you center to center U-joint measurement.

After I take this measurement, how much do I take off for suspension travel? I was told an inch or 1 1/4 inch.

And yea, the shop did mess up there but since I didn't pay anything it'll be hard to get something back. One of the lesser things about living in a small town is the extremely limited amount of people who know what they are talking about.
some of my favorite quotes are;
"Trucks don't have leaf springs on the front axle. They have something called coil springs,"
"Check the computer"
"It will cost about a lot of money to test all 8 of your injectors because we would have to take your valve covers off to get to em. then we ship them to a third party for testing."
Also the countless times people have thought it was a powerstroke.