'95 F350 4x4 5.8L/Auto
This is kinda strange I didn't see anything posted previously but when I was under my truck replacing the rear fuel tank I noticed one of two rear drive shaft u-joint straps that secure the u-joint to the axle yoke was tore off on one side. I could move the u-joint back and forth in the mount.

I replaced both straps with kit from Advance Auto and they were noticeably thicker and held the u-joint snug. I don't drive it much but after few miles estimated less than 20, I checked the straps and see now they are both stretched which is causing movement in the u-joint within the yoke again. Of course the yoke has the retainer lip that it fits in so it don't slip out but I'm afraid to drive it like this!

I might see if I can get a pic but does anyone know why this is happening? I replaced that u-joint about 3 years ago and it's been fine even though I am not sure when the one strap broke.

 

Are you sure the nuts aren't backing off? I have a hard time picturing how the u-joint retainers can be "stretched".

 

I would look at the yoke, especially where the strap had broke. Perhaps it's wallered out and allowing the u-joint to not actually sit tight, causing the new strap to stretch.

 

Yes, carefully check that your U-joint bearing cups fit tightly into the yoke - they make different sized U-joints, and if by chance the one you installed has slightly smaller caps (could be too-small of diameter by only 1/16" for example), the U-joint will not sit tightly and will move around in there and that could possibly cause what you are describing.

Just thinking out loud here - I can't imagine how those straps are getting stretched besides the above, unless something is seriously bound up in the rear axle (brakes stuck on?) which I would think that you would notice while driving.

 

Try a strap kit from orileys. For some reason they are a lil bit smaller and it lets you tighten them down more. I have gotten others that fit snug aganst the yoke but it wasnt good enough. The one from orileys sits off the yoke a lil.

 

Thanks for all the suggestions... sometimes these things just need a little extra thought. I think this here might be it... there is slop when drive shaft u-joint is just sitting in the yoke, with no straps or if you don't snug down all the way. You are confirming it should fit snug in there, which it doesn't. Not sure how or why these auto parts stores fail to give the right parts but I will need to get this replaced with the correct u-joint with the right size needle bearing cups.

 

unless you got a hybrid joint, there is only one size joint that will fit in your driveshaft. . .so take a bearing cap with you when sizing the straps. there are a few different sizes for the fords, and lookin up parts in general for these trucks takes a slight amount of competence from the guy behind the counter. . . albeit slight, most of them have none. i wouldnt put it past them to mess it up. ive driven mine under the worst of u-joint condition, and even shattered an ear off the yoke one time i broke the rear 4wheelin. . .that bein said i have never had a strap issue and im still using the yoke that has a partly chunked ear.

you should be able to look at the profile of the yoke and make sure the strap makes a perfect circle with the yoke. if it doesnt, its a) the wrong strap or b)its the wrong joint, or c)its the wrong yoke

if youre unsure post a pic

 

You could also replace the straps with a "u-joint girdle" Summit sells them, cups the whole cap rather then just a strap. run bout 25-30. Had to use them on my 78.

 

Apparently I do have a hybrid joint! After buying a Precision 232 @Napa (with 1-3/16" bearing caps) I found it fit the yoke snugly but it was too big to fit the drive shaft. I figured out I need a combination U-joint and ordered a Neapco 2-3050 from Advance Auto for $32. This should do it...

Combo Joint 1330 to 1350
Outside to Outside 3-5/8 X 3-5/8
w/ 1-1/16 X 1-3/16 Bearing Cap Diameter

Part numbers:
Precision 448
Neapco 2-3050
Spicer 5-648X

On another note, I am not sure if this is supposed to be like this from the factory or if the drive shaft is from a F250 - not sure if there is a difference but was told when I bought the truck the engine & transmission had been swapped out. I know the engine is from a '96. Maybe they couldn't use the original drive shaft with the swapped in transmission? Who knows...

1995 Ford F350XL
137" WB, A.T., 4x4, E4OD
10.25" Sterling rear

 

Don't feel bad, it's really easy to miss the slightly different sizes of the U-joint caps if you're not looking for it. I have had so many vehicles that I have done the driveshaft U-joints on that I can't remember which ones had what, but I have definitely come across this same issue before, and had to make a trip back to the parts store (this is where a good parts counter person is worth their weight in gold, and there aren't many of them left).

It's always good to get things fixed right - having a driveshaft come loose is a serious issue.

 

yea its most likely from the engine/trans swap. the hybrid joint is a cheap and easy fix for mix and matched drivetrain/driveshaft combos. my guess is he swapped in a trans that wasnt the original type that was in there, changin his driveshaft length. . .and he used the shaft from the donor which had the different u-joint. ive used hybrids a bunch in the past when swappin drivetrains or doin solid axle swaps in IFS vehicles. now that ya know, just buy a bunch at once and have them handy. theyre not always readily available.