Is my slip yoke shot?

[tjl006]

As posted before tailshaft seal popped out due to the bushing and or seal being defective. The slip yoke looks dicolored but feels smooth still. Do you guys think its shot?

[Stranger in the Black Sedan]

You could try lapping it with some 400 grit emery strap and see if the deposited bronze and the blueing comes off easy. If it comes off very easy, I would be okay re using it. If it does not come off with very light pressure lapping it, then I would be looking for a new yoke. The tail bushings get wallowed out from high speed use with higher ratio gears that spin the shaft too close to critical speed, from what I have read. Do you have 4.10 gears and a stock DS?

[tjl006]

I have an aftermarket high speed balanced driveshaft and an aftermarket tailshaft housing with forced lube mod. I also have 4.10 gears. I bought the tailshaft housing and driveshaft so I wouldnt have to worry about replacing them down the road. Guess I was wrong:o

[Stranger in the Black Sedan]

what aftermarket shaft do you have? They are all "high speed balanced"

[tjl006]

4in aluminum from darrin b.c automotive

[TAKEDOWN]

4in aluminum from darrin b.c automotive

Oh boy... I also purchased this driveshaft. I'll be keeping a a close eye on this thread.

[Krytin]

That should clean up fine - I would use a little finer grit than 400 for myself but if you don't go hog wild on it the 400 should clean it up pretty fast without removing too much of the shaft. Just don't stay in one spot for too long. Work your way around using a "shoe-shine" motion.
+1 on the bushing - looks like alot of it is on the shaft!
Your gonna need a new bushing.

[FordNut]

The yoke is probably salvageable, but it isn't very expensive, so I would get a new one. Maybe Darrin will send you one.

Good luck with your high speed balanced shaft. There's more to it than balancing, there is material science involved.

[Stranger in the Black Sedan]

4" 6061 aluminum has just about as high of a critical speed as 3.5 MMC shaft so as long as that shaft is not bent and balanced properly that shouldn't be the problem

[tjl006]

Cleaned up yoke majority of bushing material came off. No tangible ridges or scratches. Darrin atributed the failure to defective tailshaft housing bushing. I doubt the problem was the driveshaft. Darrin also offered to replace the slip yoke if I felt it was damaged. At this point I think its okay.

[Stranger in the Black Sedan]

defective bushing sounds like a sketchy explanation, but I guess you will find out soon enough if it fails again, that you need to check the straightness and balance of the shaft. Ford has a TSB for the bushing and seal failing, as a result of driveshaft vibrations, on the CV's

[Darrin]

defective bushing sounds like a sketchy explanation, but I guess you will find out soon enough if it fails again, that you need to check the straightness and balance of the shaft. Ford has a TSB for the bushing and seal failing, as a result of driveshaft vibrations, on the CV's


It isn't a sketchy explanation. There were several of these bushings that were out of spec for their outer diameter and have done this and I am not the only one who has seen it. I had 3 in the last month and found them to be just a couple of thousandths small in diamater. The vendor was already aware of the problem when I called them and has sent out replacement bushings. I am replacing anything that was damaged as well.

Also, that shaft was definitely doing some very high rpm and that one failed much differently than any of the others. The others just spun loose and popped the rear seal. On that one you can clearly see that it was getting hot and the bushing tried to become part of the yoke. None of the others had anything like that. I haven't yet gotten an answer to how fast the car was going, but it wasn't the speed limit that's for sure. LOL

I have never had a lube modded vehicle have that kind of damage before actually and some have been WAY fast. I really do want to know how fast the car was going.

But, even though that definitely doesn't loiok like damage caused by vibration, it could be. The only reason for that would be that the shaft might have been damaged in shipping. It's a long shaft and something could have happened. These things are built by a VERY high quality company and are balanced to the nth degree. There is no problem with the craftmanship or materials.

To eliminate the possibility of damage or imbalance I highly suggest taking it to a reputable driveshaft shop to be checked out. If it's out of balance I will pay to have it balanced. If it's bent then it's trash and we need to make a claim on UPS for it.

Darrin