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'99 & up 7.3L Power Stroke Engine and Drivetrain Discussion of the '99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

Thread: Rear axle pinion yoke question, '99 7.3L F250 Reply to Thread
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  Topic Review (Newest First)
05-26-2016 03:12 AM
klhansen Closest I can suggest is see if the yard has the build date on the trucks you're getting the yoke from. The closer is is to your truck, the more chance it has the same yoke.
05-25-2016 10:23 PM
FloorPoor One more stupid question.
Is there somewhere I can find out if my rear axle is the long or short spline variety by using the axle tag #? My rig being a very early production 99, it's most likely a long spline, but I would like to be sure.

I've located both yokes at a local salvage yard, but I prefer to have all parts on hand before I tear stuff apart, rather than making a parts run in the middle of a job. That lessens the possibly of loosing parts and/or, my dumbass forgetting how stuff goes back together.

Thanks.
05-17-2016 12:17 AM
FloorPoor It could just be cup wear, the play is mostly end to end on the u joint. But I'm still thinking that running it loose for a few thousand miles is what caused it.

I won't be able to get to it for a week or so (no fun tickets) and I'll have to drive the truck, but I definitely won't tow anything until I fix it. I got pretty good at babying the drive train when the clutch would slip every time I spooled the turbo up good. But the new Luk disc and flywheel, along with new clutch hydraulics feels great. I want to really get on it, but I don't want to break more stuff.

And thanks for the tip on just pulling the axle shafts, I forgot how easy it is on the 10.5
05-16-2016 10:18 PM
klhansen
Quote:
Originally Posted by FloorPoor View Post
"Sprung" is when the twisting force of the driveline spread the yoke a few hundredths of an inch wider than it should be, causing the u-joint to have a little play even when the straps are tight, just like when you apply too much torque to an open ended wrench.
It may just have been wear at the posts that locate the cups within the yoke and control the end play of the cross within the cups. I had that happen with my front axle yoke. Fairly simple replacement, but kind of a bear, because I had to tighten, unbolt my back up wrench, check preload, reinstall backup wrench, tighten, (repeat 4 or 5 times).

You're right on the preload spec, I didn't have the book in front of me when I posted before. I believe you can also use a specific inch-pound range (lower for used bearings and higher for new bearings) if you don't have the initial preload torque measurement. I think pulling the axle shafts is easier than pulling wheels and calipers. The idea is to remove extraneous drag from brake and wheel components so you can get a consistent reading.
05-16-2016 08:22 PM
FloorPoor
Quote:
Originally Posted by 69mach1377 View Post
OK, I'll bite...What does 'sprung' mean?
Stupid smart phone, post #5 is for you.
05-16-2016 08:19 PM
FloorPoor
Quote:
Originally Posted by klhansen View Post
There should be a number stamped/cast-into the yoke. I would get that and be sure you get the right part, which should be available from about any driveline shop.

And yes, you can replace the yoke without messing with the crush sleeve (unless you get it too tight, then you need to replace the sleeve). The seal has no real affect on preload, whether you replace it or not, but it makes sense to replace the seal. What you need to do is remove the axle shafts (at least far enough to disengage them from the differential) measure the differential bearing preload with an inch-pound torque wrench while turning the yoke. Then when you reinstall your new yoke (and seal), return the preload to the same value or very close to it. As mentioned, if you get it too tight, you'll need to disassemble, remove the front bearing and crush sleeve and start over. You'll also need a very sturdy tool to prevent the yoke from turning as you tighten the nut. It takes well over 200 ft-lb to get it tight, but you need to go very slowly and check preload frequently.

Quote:
Originally Posted by kcastle View Post
I've gotten to really like using a race spacer (RA Tech 4105) instead of crush sleeves.
A spacer IMO would be way more trouble than a crush sleeve to set bearing preload. The recommended procedure is to use a new nut each time, and with putting shims in with a solid spacer, you'd be removing the yoke multiple times. The preload is measured in inch-pounds of turning torque, not end play. Even if you used pinion shaft end play measurement, you'd still be installing - removing - reinstalling the pinion yoke at least once to make a measurement.
The manual I have states that the pre-load should be measured by removing the wheels and brake calipers and turning the yoke with a torque wrench before disassembly, then set it no more than 5 inch pounds tighter on reassembly. It also says to count the exposed threads before disassembly to have another point of reference for reassembly.

And I decided after I posted last night I will definitely replace the seal while I'm in there.

Thanks for the input.
05-16-2016 08:08 PM
FloorPoor "Sprung" is when the twisting force of the driveline spread the yoke a few hundredths of an inch wider than it should be, causing the u-joint to have a little play even when the straps are tight, just like when you apply too much torque to an open ended wrench.

I'm sure it got that way because the driveline was missing a bolt up front, and the u-joint straps were loose

I was swamped busy last fall, so I had to take the truck to a shop when the front axle seals started leaking badly. I had them replace all the u-joints while they were at it.
It WAS previously the only shop I trusted, but I had to take it back because the seals started leaking again within about 100 miles. He made it right for no extra charge and even replaced the axle ends because he wrecked the splines on them, but I should have inspected the other work more closely. After discovering the loose driveline, and the front driveline u-joints installed with the grease fittings facing the wrong way, and one of the u-joints in the front axle a cheap non-greaseable one, I won't be taking anything else to that shop.
05-16-2016 02:07 PM
klhansen There should be a number stamped/cast-into the yoke. I would get that and be sure you get the right part, which should be available from about any driveline shop.

And yes, you can replace the yoke without messing with the crush sleeve (unless you get it too tight, then you need to replace the sleeve). The seal has no real affect on preload, whether you replace it or not, but it makes sense to replace the seal. What you need to do is remove the axle shafts (at least far enough to disengage them from the differential) measure the differential bearing preload with an inch-pound torque wrench while turning the yoke. Then when you reinstall your new yoke (and seal), return the preload to the same value or very close to it. As mentioned, if you get it too tight, you'll need to disassemble, remove the front bearing and crush sleeve and start over. You'll also need a very sturdy tool to prevent the yoke from turning as you tighten the nut. It takes well over 200 ft-lb to get it tight, but you need to go very slowly and check preload frequently.

Quote:
Originally Posted by kcastle View Post
I've gotten to really like using a race spacer (RA Tech 4105) instead of crush sleeves.
A spacer IMO would be way more trouble than a crush sleeve to set bearing preload. The recommended procedure is to use a new nut each time, and with putting shims in with a solid spacer, you'd be removing the yoke multiple times. The preload is measured in inch-pounds of turning torque, not end play. Even if you used pinion shaft end play measurement, you'd still be installing - removing - reinstalling the pinion yoke at least once to make a measurement.
05-16-2016 12:21 PM
kcastle Being a 99, it is most likely a long yoke.

Short Yoke = 3.125 inches
Long Yoke = 3.500 inches

I've gotten to really like using a race spacer (RA Tech 4105) instead of crush sleeves. The pinion seals are cheap. Why not replace it while there.
05-16-2016 11:00 AM
69mach1377 OK, I'll bite...What does 'sprung' mean?
05-16-2016 12:52 AM
FloorPoor
Rear axle pinion yoke question, '99 7.3L F250

I was under my 99 f250 7.3 this weekend replacing the clutch. While removing the rear driveline I dicovered that the rear pinion yoke is sprung. I didn't have the part available, and limited time to use my friends shop and lift, so after the clutch install we buttoned everything up and drove it home.

My question is this. The rear pinion seal is not leaking, so is it possible to remove the damaged yoke, leave the seal intact, and install the replacement yoke? I'm familiar with the proper way to pre-load the pinion bearing, but I'm not sure if using the old seal with a different yoke will cause issues with the pre-load process, or if it's even possible to r&r the yoke without wrecking the seal. I'll probably put a new seal in while I'm in there, but I'm just curios.
Also, Ive been looking online for parts and I can find yokes listed as short spline, or long spline. How do I figure out which one my differential needs before I remove it? I would prefer to do the r&r in one shot, rather than remove the yoke and wait for parts. This truck is my work rig and I need to keep the down time to an absolute minimum. And if any of you have a spare yoke (used) lying around that is NOT sprung, I'm interested in purchasing it. I need to keep cost to a minimum as I've totally blown my maintenance budget with the new clutch and hydraulics, as well as some stuff I had to do last fall. And the poor old beast needs tires in a bad way too. I love this old truck, but the maintenence costs have got me seriously considering going back to a gas pickup or commercial van.

I appreciate any input, thanks.

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