Driveline vibrations

Correct mine is the one on the right and I bent it.


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yes, they use a crush sleeve.

if your going to do it, new bearings, races, and crush sleeve.

slide axle shafts out a bit.

drop out carrier, replace inner and outer pinion bearings and races.

put new crush sleeve in, new nut, and tighten it down to I think it was something like 25-35 in/lb of drag, which is a fk load of torque, if your looking for that spec. well into the high hundreds of pounds. we just cranked up the line pressure on the impact to like 175 or something and still almost didn't get it. depending on your situation, you might need to slide the axles back in, push on the brakes, and put a very long cheater bar on a 3/4 breaker bar. note i said very long cheater bar. if you need to do it that way, you will be surprised just how fking tight it actually is to get to the required drag. make sure you slide the axles back out of the carrier before you do your drag check. the spec is for just the pinion and the carrier, not pinion, carrier and axles etc.

when you get your in/lb of drag, take a hammer and punch, I used a 3/4 piece of round stock so as not to fk something up and crack both the yoke and the inside of the rear end on the pinion shaft and recheck your in/lb of drag.

repeat that last step over and over till you don't get a change in the drag. you will beat the new races in, they will feel totally seated, but they wont be. you preload that race, and crack it, it will seat more. i think when we did mine we ended up tightening and cracking it like 5 or 6 times before we didn't get a change in drag.

On new bearing and races, try to shy towards the higher end of the drag, if your reusing bearings or races, stay towards the middle of the drag.

this would also be a good time to put in a tru-trac if your haven't already, and for chits and giggles, replace your carrier bearings. just make sure to NOT get the koso bearings. get good old timken bearings, or don't bother.

randy's ring and pinion is where i got all mine from. They have a complete kit, if you go that far. or pieces of a kit.

I've done an old Dana 35 in a jeep, and it was a pretty good challenge getting enough torque on it, but overall not a bad job. I don't have any 3/4" drive stuff so it may really be a challenge to get this one tight enough. I usually do all of my own stuff, but what does a shop charge to do something like this? I might save myself the hassle and let them have at it.

Harbor freight had a 3/4" drive set for $65. I've gotten lucky and not had to buy it so far but I might go pick it up one day just in case I ever need it.

There is different rear ends in for instance like my 99 F350 if it had the Dual rear tires it would have the Dana rear end single F350 rear it has a in-house Ford rear end one has Crush sleeves one does not

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Mine is the SRW and is the Sterling 10.5". Crush sleeve is likely in there. I'd like to be able to just tighten the yoke down and call it a day, but i'm concerned about the bearing. I've got 230k on the truck, so it's probably time to do it all.

kleake said:

Mine is the SRW and is the Sterling 10.5". Crush sleeve is likely in there. I'd like to be able to just tighten the yoke down and call it a day, but i'm concerned about the bearing. I've got 230k on the truck, so it's probably time to do it all.

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Mine has 267000 miles and the rear end shop used a used yolk for $40 and installed for like 20 bucks.
I would imagine they at least replace the seal but I did not confirm and Ten Thousand Miles later still works great no leaks.
Since this was a well-known rear-end only shop I put full faith and trust in them. I was going to do it myself but just the yoke was like $120 new and obviously I was a little scared to do that. last thing I want is rear end problems


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Good to know it was a simple fix and still going good. I'm in the same boat, and my luck I would have a failure while towing and really be up a creek. I'm going to try and inspect it this weekend. If all looks good and the bearings feel smooth, i'll just tighten and monitor. If there is any roughness at all, I'll have to go in deeper.

When I had my 6.4,I had a pinion seal leak. I spoke to a Ford tech about the crush sleeve and he said you can just tighten it down and it should be fine. Once I started, I found that the yoke nut was a bit loose. Replaced the seal, tightened it all down and had no trouble to the day I traded it in (about 35k).

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Wizbangdoodle said:

When I had my 6.4,I had a pinion seal leak. I spoke to a Ford tech about the crush sleeve and he said you can just tighten it down and it should be fine. Once I started, I found that the yoke nut was a bit loose. Replaced the seal, tightened it all down and had no trouble to the day I traded it in (about 35k).

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Good to know, thank you! Hopefully that is what I will find as well.

Well, the saga continues........ This shouldn't be this difficult!

I pulled the flange, inspected/felt the bearings and all checked out good. Put it back together and I still have driveline vibrations at 65-75mph. Anything below that is smooth. Took the driveshaft back to the shop, they adjusted the balance but say it is perfect and no more than .002 runout on the whole shaft. I put it on the truck and i can see approximately 1/8" runout towards the rear half of the shaft. I put it on jack stands and run it up to speed and right at 65-70 you can definitely feel driveline vibrations that were never there before. After 75 they slightly diminish, but remain up to 100. They aren't 'bad' but enough you can slightly see it in the mirror and you can hear it as a drone is there. I'm not being picky and I am sure this will work, but over long term I don't like it especially since those are the speeds I drive every day and it's going to cause other issues. Per the driveline shop, they say the only thing at this point they can do is go back to a 2-piece shaft.

Any other ideas of what might be happening?

Questions:

1. Both small weights are at the ends of the shaft, but could they need to move a weight to the center of the shaft?

2.Could the slip joint be flexing at speed?

3. Why does he not see any runout on his machine, but I can see it on the truck, and both flanges have zero runout?

4. Should I just have him build me a complete brand new shaft? Aluminum for lighter overall weight? Or just go back to a 2-piece and fix the carrier height to fix the low speed shudder.

Video of what I am seeing on the truck. I move around on the shaft, but I see the most runout in the very center: https://youtu.be/draBgtzSnDg

If the runout on the shaft is .002 while on their lathe, then you've got to have something else wrong. I'd suspect it's not mounting up correctly to the yoke or the yoke itself. That's very strange.

The flange is what i'm wondering as well, but the odd part is it didn't have that vibe before, with the same flange. I didn't get it in the video, but if you look at the flange while it's running, they 'appear' perfect and you can't see any runout at all. Unfortunately you can't really check the slip yoke end as it's all cast steel and it looks all sorts of out of whack. By the time you get to the tube, it's definitely got the runout there.

Welp, still having issues. The shop re-balanced it, no difference, so they re-tubed it and,,,, same issue. No visible runout on their machine, but definitely visible on the truck. Front looks perfect, rear end of tube right before the slip joint looks to be 1/16" or so off, but the yoke on the axle looks perfect. He is suggesting going back with a 2-piece, but wants to keep the truck for a day to go over everything. We are both kinda at a loss since everything looks perfect until it's mounted up. Gotta figure out how I can leave the truck with him for a day and see what he comes up with.

I had a one that the yoke had to be bolted to the flange in one certain position otherwise it would vibrate. But that was flange mount yokes on each end instead of a slip. Not sure if you could try putting it on the splines in different positions or not. Or that flange on the axle side.

That's what I have is a flange on both ends with a slip joint in the rear portion of the driveshaft. The flange had never been removed, but was found to be loose. (probably from the 235k miles that are on it). We tightened it and had vibes. I pulled it off, inspected everything and put it back on, likely in a slightly different position but no change. I might try marking the driveshaft as it rotates, then move the yoke 180 and see if it changes. That would tell me if it's the yoke or the shaft at least.

so the flange on the axle is fine, no run out, but the shaft right on the other side of the u-joint as some run out, but only when on the truck?

how old is the u-joint?

you probably said, but I'm not flipping back through a few pages looking.

and all 4 bolts that mount that flange to the yoke are useable in any position, meaning you can rotate that shaft 90* and use each of the 4 positions. one of those 4 should fix you.

New joints when they did the shaft. And yes, the flange has 0 runout. The rear portion of the shaft is cast and is the slip joint so it's impossible to check runout there. Just in front of the slip joint at the start of the tube (~12" in front of rear joint), there is a small amount of runout.

I just marked the shaft as it rotated, then turned it 180 degrees on the rear flange and marked the shaft again. The marks are in exactly the same spot telling me it's the shaft. Now I have to say this one LOOKS better than the first time, but it actually has more vibration. There is about 8 marks on the shaft where he was testing the runout on his machine and it was within .008 over the full length, so nearly perfect.

Starts vibrating on jack stands at 67mph, is strongest at 73mph, then tapers off a little but remains up to about 85mph where I stopped testing. There is no mistaking, it's definitely driveline vibrations for sure. Maybe it's simply out of balance even though it was checked a total of 4 times?

I'm at the point that it's got to be something with his machine, but it's really odd that it is perfect on there but vibrates on the truck.

I'm pulling the yoke and verifying bearings and a new seal while I'm in right now.

All back together, no change at all.... What about the balance weight on the rear flange??? Could it be out of balance and I never felt it before, until the 1-piece shaft transmits the vibration to the transmission? No driveshaft and it still vibrates, I just don't feel it? I'm grasping, but that weight isn't rotating perfectly like the flange itself is. It doesn't look bad, but it is rubber mounted. I'm lost as to what else it could be.

FIXED!!! The rear flange on the axle was to blame! There is a balance weight on the flange similar to a harmonic balancer. It is rubber mounted and I guess over time had moved somehow. I put hose clamps around this balancer and was able to get rid of about 90% of the vibrations. I debated just taking the balancer off with a press, but I was able to hunt down a new one on ebay for $50. Put it on and all vibrations are gone. Best I could tell, it's likely been vibrating for quite a while explaining why my pinion seal was leaking and the flange was a little loose to begin with. I couldn't feel it due to the two piece driveshaft, but with the 1 piece it was transmitting that vibration a lot more. Glad to finally have this fixed, and now I can say that the 1 piece shaft is MUCH better all the way around. In case anyone else runs into this issue, the PN is 8C3Z-4851-A