[falcon11998]

I have a 2005 M6 GTO making a little bit above stock HP, when I purchased it there was already a one piece 700 hp driveshaft installed. I broke that one at high speeds due to it not being balanced(I think) and replaced it with a DSS 1000hp single piece with their billet 4 bolt pinion. I still get bad vibrations above 120 and I don't dare push the car past 135, i've been chasing the vibration for the past year with various bushing etc but nothing helps so I bought a DSS 1000hp 2 piece that will mate to the 4 bolt pinion I already have. Problem is I never had the original center support bearing bolts and i cant find out what size they are.

In a nutshell-
Need to know center support bearing bolt sizes
Why is my car shaking at high speeds
Does anyone want to buy a lightly used 1000hp DSS singe piece? Part number is GTOSH3-A

 

[Nothubertjfarnsworth]

you might want to check the driveline angles to make sure both u-joints are going to be at the same angle, so that their motion cancels each other. trans and differential centerlines should be parallel, even though they are offset.

i would get a thread detective from a hardware store, climb up under the car and start trying it out on the bolt holes for the center support bearing.

 

[falcon11998]

Excuse my ignorance but how do I do that?

 

[Nothubertjfarnsworth]

The Driveshaft Shop | Angle Calibration

The Driveshaft Shop

www.driveshaftshop.com

they do make a variety of tools to accomplish this. they make angle finders specifically for checking this sort of thing, and some guys on here have used apps on their cellphones to do it, too.

 

[LS2-GTO]

Tremec makes an app that has a Driveline Angle Finder function. I have not tried it yet but it guides you through the process.

 

[falcon11998]

Thanks for your responses. I got the tremec app and I will try it tonight or this weekend.

 

[GTO44]

The Bolt size for the center carrier bearing is 10mm - 1.50. I had to tap one of the holes years ago when I installed my DSS 1000hp 2 piece. One hole was stripped from the 5 different driveshafts i've had in and out over the years lol. Found a pic of the tap I used and it was 10mm-1.50.

That brings me to your vibration problem. I tried a 1000hp 1 piece. No matter what I did I couldn't get the vibration to stop. It was down right scary past 120mph. Doing high way pulls with my buddies in "mexico" was a no-go with the 1 piece. Felt good at lower speeds though, with how connected it felt vs the stock 2 piece and the two other after market 2 piece stock replacements I tried and blew up.

I finally went to the best driveline shop in my area and had them take a look. They said everything was great with the pinion angles and the driveshaft was perfectly balanced.... So I gave up, sold the 1 piece, and bough the DSS 1000hp 2 piece with the aluminum/chromoly combo. One of the best upgrades I've ever done. Has the solid connected feeling like the 1 piece but has the smoothness of the factory 2 piece. Has held up great with 4,500rpm launches on drag radials at the track and super sooth all the way up to 155mph where the factory governor kicks in.

Here's a couple pics comparing the stock ds, vs the 1 piece, vs the DSS 2 piece... and a couple close ups of the bad ass heavy duty center carrier bearing on the DSS 2 piece

 

[falcon11998]

Awesome reply. I feel a lot better considering that’s the exact 2 piece I purchased. I would be downright angry if I spent 2k on driveshafts and never solved the problem.
Thanks man.

 

[falcon11998]

I installed the two-piece driveshaft and immediately the problem was solved. Doesn't feel any different than the 1 piece and I can go 155MPH with little to no vibration.

For the record the stock threads for mounting the center support bearing are 1/4-20.

GTO44 i read your post wrong and didn't realize you tapped the holes to 10mm-1.50 so when i tried to use the bolts obviously it didn't work. I still have the exhaust off so i might go ahead and drill and tap them for that size anyway.

Thanks for the help

 

[Sacrifice]

hmmm. ill have to find my bolts and check them. cant remember where i placed them. they shouldnt have been standard thread though.

Edit: Cant find them and not a clue where i would have put them at this point