Fresh RXT & Magnum t56 set up=strong vibration at high rpm

[KilledbyKenne]

I toasted something in my stock t56 and instead of rebuilding, I decided to buy a magnum. I found a used one for a great price and bought it. Previous owner said he had about 800 miles on it before I decided he didn't like the gear ratio. This is the one with the 2.97 first gear. So he bought another one and had this one for sale. I picked it up and bought a brand new RXT clutch and McLeod billet flywheel. Brand new clutch fork along with TOB. Replaced the pilot bearing too.

I did my clutch break in and other than what seems like an abnormally loud TOB whine I didn't notice any issues. Yesterday I took it higher in rpms than I had been during break in and that's when I noticed a strong vibration starting around 3500 rpm. It shakes the whole car. I am trying to think about the possibility of me missing a step along the way. I followed a write up on here that showed all the appropriate torque specs which I followed. I had my driveshaft shortened the required amount and the shop balanced it.

With it being rpm based and not speed based I doubt it has anything to do with the DS.

Any ideas? I'm racking my head and I'm just really hoping I didn't get hosed on the damn Transmission.

Thanks for any help you can provide and I'll answer any questions to help get some ideas flowing. Let me know what you can think of please!

 

[xtreme_exploder]

If it's not speed based then it's probably a clutch or flywheel issue. Does it do it in neutral when you rev the engine up? What about revving with it parked, in gear with the clutch depressed? This way you can single out anything from the transmission back from being the issue.

 

[KilledbyKenne]

I did test it in neutral and it had the same vibration. I forgot to mention that in the original post. I assumed the flywheel/clutch were good since I bought them brand new. Any ideas specifically what the issue could be with either of them?

Thank you for the response.

 

[xtreme_exploder]

If you do this enough, you'll learn to never trust even new parts lol. Everyone messes up. McLeod has good customer service if you don't see anything obvious when you take it apart, give them a call. It's gotta be clutch or flywheel related. Check your work first. Did you install a new pilot bearing? If they forgot to balance the clutch or flywheel, that'll vibe bad too.

 

[KilledbyKenne]

Pilot bearing is new. With the vibration still happening in neutral, I am leaning towards something with the flywheel. I'm done with the car for this year. I don't have a heated garage so I'm not going to lay on the cold concrete to tear it down again. I'll wait until Spring.

 

[xtreme_exploder]

Oh man sounds like you need to throw a heater in there lol. I put a Mr. Heater natural gas heater in my garage and makes it nice and toasty even down to the single digits out. Doesn't use much gas and my garage isn't even insulated.

 

[oldmodman]

Under the test circumstances you mentioned it is in the flywheel/clutch/pressure plate assembly.

One way to be absolutely sure is to fire up the engine again after you pull the transmission again. If you fell the same vibration it's definitely the clutch assembly. If the vibration is now gone it has to be something related to the trans.
And I HAVE ABSOLUTELY NO IDEA WHAT THE HELL THAT COULD BE! But.............

Did you change the bellhousing too? It could be mounting the trans out of alignment. Did you test the bellhousing for concentricity when you installed it?

 

[KilledbyKenne]

Thanks for the reply. I used the stock bell housing.

I was watching a few videos on YouTube about balancing and found someone that said they had their clutch and flywheel balanced together. Is this a requirement with these cars? Both the clutch and flywheel are mcleod, but they were not purchased together. There was no marking on the flywheel to show where the clutch needed to be mounted either.

Thanks again for everyone's help.

 

[KilledbyKenne]

Thought I'd update this for any members that have this issue in the future. Turns out my passenger front shifter bolt was just barely making contact with the trans tunnel. Pulled the tunnel away from the trans a little and no more vibration. Good day yesterday.

 

[Trenton_Brock]

McLeod's customer service sucks! I have the RXT and its made a noise since day one and its getting worse. Called them and they said I could buy another one and send the other back. But if it checked out ok I would own 2 clutches and they wouldn't credit my card back.

 

[Stage 4.6]

McLeod's customer service sucks! I have the RXT and its made a noise since day one and its getting worse. Called them and they said I could buy another one and send the other back. But if it checked out ok I would own 2 clutches and they wouldn't credit my card back.

I don't like bashing companies of just one experience, but when you pay for a product as expensive as these RXT setups (clutch, flywheel, TOB, etc...) The company should have some good customer service available. had a professional speed shop install mine I called Mcleod Customer service in reference to my TOB issues and the guy I talked too sounded like he didn't have a clue about cars period.. pretty much said their is nothing he can do?