# Shuddering under hard acceleration



## batmans (Aug 16, 2007)

Just noticed it this morning under hard load in the higher RPMs that I'm getting shuddering symptoms in the back.

This is in straight line acceleration.

Does this mean that my Torco SG-1 with Ford friction modifiers needs replacing after 30k miles?

Or is there something else I need to worry about?


----------



## svede1212 (Nov 1, 2005)

Check your drive shaft donuts (rubber couplers).


----------



## batmans (Aug 16, 2007)

do tell me more.....


----------



## batmans (Aug 16, 2007)

It sounds a little like this, but only at mid to high RPMs.


----------



## batmans (Aug 16, 2007)

But if I upgrade the driveshaft to something like this: The Driveshaft Shop | PONTIAC 2004-2006 GTO 3.5" Driveshaft 800HP 1-Piece Shaft - Pontiac - Domestic Driveshafts

Then do I still need to replace the donut or does it come with the kit?


----------



## svede1212 (Nov 1, 2005)

That driveshaft replaces the donuts with old school Spicer universal joints. I have an older 550 HP DSS shaft. I know if you have torn donuts they are ridiculous to replace with OEM. I've seen them on eBay for over $100 each.


----------



## batmans (Aug 16, 2007)

are there any aftermarket solutions? Like pedders?


----------



## motoristx (Apr 27, 2010)

i replaced mine with a 3.5" carbon fiber drive shaft... it eliminated all the donuts in the shaft and replaced them with the universal joints. I get very smooth acceleration now, no vibes under the car at all, also reduced wheel hop quite a bit (I was surprised at that fact).


----------



## batmans (Aug 16, 2007)

motoristx said:


> i replaced mine with a 3.5" carbon fiber drive shaft... it eliminated all the donuts in the shaft and replaced them with the universal joints. I get very smooth acceleration now, no vibes under the car at all, also reduced wheel hop quite a bit (I was surprised at that fact).


Got a make and model?


----------



## svede1212 (Nov 1, 2005)

No Pedders doesn't make the couplers. I'd check out gForce 1320. He has a nice selection of drive shafts. The Drive Shaft Shop also carries some.


----------



## batmans (Aug 16, 2007)

Turns out it was my worn out plugs after 30k miles. 

I replaced them with the Iridium NGKs.


----------



## svede1212 (Nov 1, 2005)

Where those stock plugs? They should last 100,000 miles. If they went bad that quickly you either got ONE with a manufacturing defect or if they were all kind of bad something wrong with the engine/tuning.


----------



## batmans (Aug 16, 2007)

No, are not stock plugs.

I'm running a colder copper plug with 8.5psi of Maggie.


----------



## Gotagoat (Jan 6, 2006)

Slightly off the subject, I've never removed the plugs in my '05. Is it advisable to move them after six years and apply some oil to the threads?


----------



## svede1212 (Nov 1, 2005)

batmans said:


> No, are not stock plugs.
> 
> I'm running a colder copper plug with 8.5psi of Maggie.


That sounds reasonable then. You should swap those out every 20K or so.


----------



## batmans (Aug 16, 2007)

Gotagoat said:


> Slightly off the subject, I've never removed the plugs in my '05. Is it advisable to move them after six years and apply some oil to the threads?


yes, and I always apply grease to the threads. Usually the grease from Amsoil.


----------

