I have noticed that I have a little bit of slop in my drivetrain somewhere, and it is most noticeable when I let off the throttle and coast, then get back on the gas. There is a slight clunk, not really a sound so much as a feeling.

Anyway, I've been reading up on the symptoms of a loose driveline support beam and had a few questions. First, one of the symptoms was being able to see the shifter move sideways when throttle is applied. I checked that on mine, and it moves a little, but it's not a drastic amount or anything. Possibly an 1/8" or so, and it isn't a sudden movement either. How much movement is normal?

Secondly, will I be able to check the torque on the beam mounting bolts without dropping the exhaust system? When I had my catalytic converters removed, they welded straight pipe in their place. In other words, there is nothing to unbolt. The only place to disconnect the exhaust is at the collector flange of the exhaust manifold; otherwise I will just have to remove the exhaust manifolds.

Lastly, do these symptoms sound like something that could be caused by a loose support beam? There is no audible clunk from inside the car, and the shifter only moves a minimal amount. Is this just gear lash in the transmission or differential, or could it be a U-joint?

This is a 94 with 6-speed, 41k miles.

Any opinions would be greatly appreciated :cheers:

 

I have a 94 with a LT1 nd a 6 speed and it sounds like mine does the same thing. I don't think its the beam though. Have you been to the ZFdoc.com site? He has an explanation of what happens when the I beam is loose and it's more of an under acceleration thing. If you can't find the article on there email me and I'll point you to it.

How smooth is yours at 75 mph. I have new tires, balance, alignment, shocks and it seems like there is still too much vibration. At 75 if I'm holding it steady with the throttle, as i increase the throttle there is a strange noise. Not very loud and I hear it only when the radio is off. Something is not right and I can feel a slight vibration. I think it should be smoother. What about yours?

 

Mine is fairly smooth at 75 mph, about as smooth as a sports car can be I guess. I had the front tires re-balanced and that got rid of a lot of vibration I was having (front tires have approximately 10k on them). I'll try your experiment tomorrow and see if I notice anything you've described.

I've seen the article you mentioned on the ZFdoc website. I'll have to go back and read it again. I really think that most of the slop is in the transmission and differential. Or I may have a U-joint starting to go bad. I'd still like to check the support beam just to be safe. The part about the shifter moving a little is where most of my concern is. A friend of mine with an LT4 said he didn't notice any movement in his. I wonder if I'm seeing the symptoms of something else? Who knows.

 

Make sure the motor mounts ar ok and tight. That's another area that will cause movement in the shifter.

 

So can anyone tell me whether or not I will need to drop the exhaust system to inspect/tighten the driveline support bolts??

 

This is running off my poor memory but it seems like you can get a torque wrench on the rear bolts but the exhaust is in the way on the fronts. I think I just used box end wrenchs on the front and got them "good & tight".

 

:iagree: and I have a case of CRS once in a while.

 

Oh. one more thing. Does your drive train have a whine in it? Usually, too much lash or slop, will produce a whine. There's also an aftermarket product out there for beam supports. Do a search for them.

 

I've got a little bit of whine, by I'd heard that was normal. Also, the ZFdoc website seemed to indicate that a little gear whine was normal.

 

Well, I've got a 96 auto so I don't know how much help I'll be. I had a clunking sound moving from Park into Reverse or Drive and also on low speed deceleration. The dealer retorqued the C-beam bolts and the clunking is gone. I do not believe they removed the exhaust to do it as none of the bolts holding the exhaust up look to have been wrenched on....