Bob@BruteSpeed

iTrader: (16)

I've had a couple customers who after buying a nine inch from me, and go with using their stock length driveshaft, end up with a driveline vibration, which was cured when they went with a longer driveshaft. It doesn't happen very often, but it does happen.


Thanks, I appreciate it. Bob

BADD SS

iTrader: (4)

Not to sound like an ***, but Ive done a bunch of 9" Installs, every one needed a 1" longer shaft. If the slip yoke is 3/4 shorter than stock, he could be in reality 1 3/4" short of what he SHOULD have... That being said, it's up to the installer to verify, and if the thing is barely in the trans, common sense should dictate not to run it. I'm not a fan of spohns customer service though either fwiw...

heymoej

iTrader: (67)

with what bob from brute speed said........his application needs an inch longer.

so its already an 3/4 shorter than the stock shaft in the pic + it needs an extra inch over the stock shaft....

so the one he ordered from spohn is 1" 3/4" to short?

good luck!

litle88

iTrader: (20)

If you guys look at the links I posted from the ws6store or lmp (who I don't blame because they are just selling it the way Spohn is advertising them) Spohn is selling them this way! They don't say to measure they are seeking it as a bolt on as long as you choose your transmission type and rear end! I ordered the one that applied to me. Read their email to me, they say that that is the right one from the looks of the pictures. If they would of said to measure anyways on their link don't you think I would have?
Thanks for the input so far guys.

cantfind2nd

iTrader: (24)

always measure . its up to the end user to verify fitment of any aftermarket part .

litle88

iTrader: (20)

Let me ask you this do you think guys that order from TEA TFS AFR LPE WCCH AI and ask for a certain CC chamber actually measure the cc's? Or take a valve spring off and check to make sure they put the correct spring with the correct spring pressures? NO BECAUSE THEY ARE ON TOP of their game!

CLRD4TO

iTrader: (4)

A CNC'd product is going to be the same everytime. Just like if you ordered another shaft from the ws6store, its going to be the same length as yours. When it comes to an aftermarket head, the installer needs to verify things like PTV clearance and pushrod length. Just like the shaft should have been measured with the rear end.

I think your next step is to get that shaft on a balancer machine. If it is way off, spohn should warranty it. I dont blame them for not doing anything if the only issue is length.

BADD SS

iTrader: (4)

While Im on your side partly, your analogy is flawed. Because you should check the springs, you should cc the head. Nobody is perfect, check EVERYTHING, it saves you from problems like this.

25thhawk

iTrader: (3)

Whoever put that driveshaft in should have known it was too short. 1 3/4" short, it was prolly barely in the bushing. It may have cocked in the housing and broke the output shaft or the output could have broke first. Tough to tell. Sorry to see the damage. Best of luck

Ryan

litle88

iTrader: (20)

I didn't think I needed to bud, I just ordered a stock length d-s for an M6 with 1350 ujoints.
It even had it written on the box they sent me so I just took it out and ran with it.

Demonicbird00

iTrader: (17)

not to hijack, but i had a similar headache w/ spohn a few years back about there "drag sway bar" they blamed the fitment issue on everything else.

hope everything works out....get a PST DS or Dennys well worth the money

-Brandon

thedudeZ

iTrader: (14)

Guess its a good thing spohn fed me lines of BS for 4-5 weeks about shipping my driveshaft and ended up having to argue to get a refund on a part they claimed was custom made and hadn't even been started on.

Ordered a 3.5in alum pst through speedinc.

Would also use denny's or strange.

litle88

iTrader: (20)

I have my plans but here's the carnage!
Broken output shaft in fricken 2!

BlackLS1Bird

iTrader: (2)

I agree. If anything it should have messed up the splines before it broke your entire output shaft. I had one of the WS6 store Spohn driveshafts when I swapped in my T56 and had the stock 10 bolt. Worked great. When I got my 9" I decided to get the PST 3.5" at the same time. Got it all from Bob and it fit awesome.

litle88

iTrader: (20)

Help me understand how you would think its the splines first?
That thing was not all the way in as it should be and it was not riding on the bearings the way it should have been and it was vibrating like crazy and once it got too stressed the shaft broke! It broke because of too much stress on the tip of the shaft! Come on maaaan

BlackLS1Bird

iTrader: (2)

I'm saying that with less contact area on the splines, they would be the most likely place to take damage and not the portion of the output shaft inside the tail housing. Your output shaft was probably stressed from previous hard use and just happened to be the weak link in this case. Does it negate the fact that the driveshaft wasnt correct for the application? No. But I dont necessarily think it was strictly the driveshafts fault.

25thhawk

iTrader: (3)

I gotta disagree. I bet that thing was wobbling so bad that it destroyed the output bushing. Once that was gone it had nothing to keep it lined up straight. If I had to guess, I would say it broke when the dyno operator lifted off the gas. The pinion drops a couple degrees, shorting the ds even more. The yoke got bound up on the output shaft. Then the inertia of the dyno wheels broke it.

Ive seen it before on the dyno, where you finish a pull and the inertia from the rollers snaps the tailhousing. Thats alot to go wrong all at once, but under acceleration with the splines lined up, it would have twisted the splines then. Were the spline twisted in the yoke?

BlackLS1Bird

iTrader: (2)

While that is possible, that slip yoke was only about 3/4" shorter than the other. There still would have been a good 3+ inches on the output shaft. And a change of 2 or 3 degrees of pinion angle as you come off the throttle isnt going to change the slip yoke travel enough to matter. People lift trucks 6 inches and use stock driveshafts a lot of the time. But I guess anything is possible. If it was the drive shaft I wouldnt put the blame on the slip yoke, but rather on it not being balanced correctly, not tightened to the rear end properly, or a messed up u-joint. Either way, if it has a noticable vibration, dont put it on the dyno. Just asking to break something.

BlackLS1Bird

iTrader: (2)

The splines look straight in the pics. Just sheared the shaft off clean way up in the tail housing near the bearing. No matter what the cause, it sucks and I feel bad for the OP. Trying to do an upgrade and something bad happens. Best of luck with the repairs and hope to see it alive and well soon.

litle88

iTrader: (20)

Thanks fellas, when the tuner was on the dyno for the first time he was only accelerating looking at the fuel tables, when he finally put it on 4th gear is when it started vibrating so he put it in neutral and coasted with no vibration from only like 4k. He did it again to show me and then when he let off is when the **** broke so 25thHawk you are correct sir. The guys at the shop said the same thing 25thHawk said about the bushing and they have seen it many times.

Here is a zoomed in picture of where it was making contact, do you see the spohn ds on the left and stock ds on the right. Can you see where the rear seal is riding? Clearly not enough is it?