Greetings,

I just got a 2004 C5 Corvette with an automatic transmission, and it has 24K miles on it. It is a one owner and it is in really good shape. It also appears that the car was well maintained and it was not hammered on. I have been looking into some simple mods so I contacted a local Corvette shop. In a conversation with a very experienced and reputable Corvette mechanic the topic of the torque tube and the rubber couplers (guibos)? came up. I was told that it is a good idea to change them out because if they are not already bad, it is just a matter of time before they will be.

He said that even if the car was not driven hard to create a problem, that time can be an issue for them too as they crack and become brittle. He stated that it is a known weak link with C5 Corvettes. For mods I will not be increasing the stock HP, as I am only interested in doing some suspension mods, and some new wheels and tires. I for-sure am doing new cat backs and an cold air intake.

At this time it seems like I have no apparent problem that I know of concerning the rubber couplers. I like being proactive, but when I learned of the cost and labor to do this work I almost passed out. I guess if you are going to the trouble of replacing them you should just rebuild the entire torque tube. Should I be proactive and have something repaired that isn't broke yet? Is this just an accident waiting to happen and I will be doing these repairs down the road?
If the rubber couplers fail what sort of damage will happen to my Vette? I will be retiring next year and I have more disposable income now. Please advise, and thank you in advance.

Thanks, Edgemere

 

As you noted, expensive.

Mine on my 2002 are apparently fine at 189k miles. Knock on wood.

 

My 2001 C5 Auto has 117,000 miles, 23 track days with 6,000 upshifts at wide open throttle from 2nd to 3rd on it.

Stop worrying.

 

I would absolutely not pull the powertrain JUST to replace guibos that aren't giving you any issues. They won't just catastrophically fail and destroy anything. If you start noticing weird noises at idle or vibrations under load then it's time to look at them. If you pull the 4Lshitty out when the clutches land in the bottom of the pan, you might as well put new ones in while everything is out.

 

Similar to above, if there are not any unusual noises, I wouldn't take apart jut to inspect. Not exactly the same thing, but when I did my clutch a couple years ago, I inspected mine (while I had the TT out) and they looked like new.

 

Here's how mine looked when I replaced the clutch with around 130k on them




The guy at the shop who pressed in the new TT bearings said these guibos were in pretty bad shape

 

OP has an auto trans. Much easier on the couplers than stick shift cars.

Not sure why this mechanic would even mention replacing them unless he was just fishing for easy money.

 

It about $800 labor to remove and replace your driveline, so it makes sense to add additional work items where that is part of the job to begin with. I should add that while I had my 2004 27k coupe out for a clutch, I had them check the torque tube couplers. They were not found to be cracked, but the rubber was rock hard from age, so for $100 in parts I had those changed.

If you plan on addressing this, I would recommend the following for your consideration:

In addition to the torque tube, replace the trans seals. Not a rebuild, just the seals. The rear crank shaft seal is another item to check.

Change rear end gears. Probably the best bang for the buck, and 3.42s will wake up performance without adversely affecting daily use.

A higher stall converter. Not a race high stall, but something around 2000 rpm so “when” you decide to add a street cam, you won’t have to worry about creep while idling. You won’t even notice that level of stall daily driving, but it will give more power off the line.

I know you stated you only wanted suspension mods, but that’s what I said before…😁