BLOWNBLUEZ06

I had a custom built driveshaft done at the Driveshaft Shop. It's a 3.5" with billet ends and I'm also using their Urethane couplers.
I was taking the torque tube apart to replace the bearings for the heck of it and discovered some very strange wear on the couplers.
Wondering if anyone has ever seen this before. What baffles me is the uniform wear 120 degrees apart from one another and the fact that the wear is so close to the bearing support. I have never felt even the slightest vibration from my car. Considering the prop shaft spins the same RPM as the motor (unlike a driveshaft only spinning a fraction of the speed), I would expect enough vibration to throw me out of the car if anything was off by the amount of wear shown. I am measuring 4.410 across the coupler and 4.340 across one wear spot. That's .070"!

The only thing I can come up with is the couplers are getting hot and distorted at high RPM and wearing this way. This coupler material is very hard. Not soft like rubber though.

Ideas welcome!





See the flat spots every 120 degrees??

TT Z06

Is there a spot in the tube that out of round?

BLOWNBLUEZ06

No way. The bearings are in perfect shape. Nice and smooth. No flat spots in the torque tube. They wore all the way around the inside of the tube too. See the partial piece I peeled off?
This is the kinda weird stuff I lose sleep over.

TT Z06

That is weird. I would call the DSS and direct them to this thread. See what they think might have been the issue. Possibly a molding issue with that coupler.

Mike04

I'm assuming you have metal spacers inserted in the coupler, are they all the same exact length? The coupler could be pinched together in areas causing the area to be slightly more dense throwing the balance out.

Just my shot in the dark.... Good luck!

HP_Addict

The couplers will deform under load and rub the inside of the torque tube. I had to scrape the remains from the inside, when mine failed. My wear was uniform though. I have no idea why yours are at 120 deg. Strange. I want to know why.

BLOWNBLUEZ06

Yep. These are the ones that RPM sells. They have metal sleeves in them, so you can't crush them.

There's a pic of them about halfway down.

http://www.rpmtransmissions.com/drivetrainparts.html

95wht6spd

IS there 3 spots or just 2?
I am guessing the spots are where the whole assembly is the heaviest, and when spinning this moves enough to throw it against the inside of the tube?

Z06wanted

Maybe ist's the load of the bolts on the coupler. See what happens when you have nothing better to do.

BLOWNBLUEZ06

It's 3 spots. and alternating every 60 degrees on each end.

I measured the OD of this coupler. It's 4.410".

Here's my couplers



and here's a stocker



Now I mentioned that mine are worn ever 120 degrees and 60 degrees off from each other at each end, so that means that every 60 degrees, there's a flat spot on one end or the other. Got me wondering if GM flattened these on 6 sides for a reason.
Things that make you go HMMMMM.

BLOWNBLUEZ06

I might agree except there's some metal sleeves in there to keep any crushing from going on.

golfinz

Place a stock coupler on yours to see if the flat spots match up

CamminC5

If you want to verify against a stocker but don't have it I'll send one via next day in the AM, but only if you swear on your LIFE to send it back. :

outlawdart

looks like it's just deforming the coupler from the torque.

BLOWNBLUEZ06

Thanks man. I got my old stocker up in the attic. I think we got it figured out

I agree Doc. It makes perfect sense when you consider where the pressure is applied. That's exactly where it's getting squished and rubbing. Thanks

Z06wanted

Maybe you need that ECS torque tamer?

Its Bruce

In relation to the 2nd picture, the torque is transmitted clockwise, right?

slow ride

Looks like the couplers are winding up under torque load as others have said. Looking at the back of the engine the drivetrain would turn counter clockwise and the load from the drivetrain is trying to stop it and it wads up the coupler just a bit under peak torque conditions.

one fast zo6

your ride is to fast, better put it back to stock and be safe!

Chris Stewart

Did you hear/feel anything during accel/decel/turns? Maybe it's time for this: