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Discussion Starter · #1 ·
Welp, as the title says, my drive shaft is extremely hot. as well as the front of my rear diff. I know this cause I had to pull my drive shaft ( I have a double cardane with an SYE) because of a bad vibration that turns out to be ( I think) a bad rear ujoint. After removing the drive shaft I also found a seized slip yoke. Not good. I spent an hour hammering that damn thing apart. Yes I greased it, like a year ago. lol. Once apart it looks like the spline coating is melted. Which could be possible since it was hot to the touch when I removed it. Pinion bearing seems OK. I haven't checked the diff oil today but I did recently. I will check it tomorrow. The exhaust was hot and I had only driven it a few miles prior to removing the DS. My questions are, Could my Cat be plugged causing the exhaust to heat up and also heating up the DS? Did the DS get hot enough to melt the spline coating and cause the slip yoke to seize causing the ujoint to fail. Or did the ujoint fail and the vibration cause slip yoke to heat up??? Or, captain obvious, it failed from a lack of lubrication???

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:unsure: I'm thinking your driveshaft u joint probably started the cycle and then the vibs took over to finish the rest.
 

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Spline coating is news to me, I don't think I've ever seen that before. Definitely looks melted I guess.
Replace u-joint, grease, and reinstall. Go for a drive and then recheck the shaft. If its hot then you know it aint the ujoint.

Depending on how much money you have to throw at the issue, you could try one of those spintech high flow cats and see what that does if you really think thats a possibility.

Where does your exhaust exit? Mine is cut off and a turn-down welded to it so it exits right in front of the axle, probably heating my axle tube a bit too much.

I'd have to believe the slipjoint was stuck because the grease had melted out of it. Maybe keep it lubed more often or find a way to cool it down.
 

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One other thing that can cause a hot cat is a miss. Mine turned red once and caused lots of stuff to melt and get smoke coming from the carpets. But a hot diff is normal, they get real hot. It is normal to have one hot enough to not be able to touch it. As far as the blue coating goes, it can get worn. The question is: Are the splines tight or loose now. That would cause some vibes in itself
 
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Discussion Starter · #5 ·
I already ordered a new Adams drive shaft. And difficult as it was to get that yoke apart, I don't think I can get it back together, without grinding that Teflon coating off. And I learned my lesson, grease, grease grease.
Once I get the new drive shaft installed I will check the cat temps.
Fwiw, I measured the distance between my tcase and rear diff yokes and got 31". Adams needs that to custom make the DS. Btw, Tom woods are delayed because of supply issues. Thanks guys.
 

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Discussion Starter · #6 ·
I guess I should have mentioned, the pinion side of the diff was hotter than the back of the diff, leading me to believe the heat is not caused by the diff.
 

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Good luck with the new drive shaft. I have gotten two 1350 D44 yokes, one from China I think and the other from Adams. The Adams yoke was much nicer
 
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