Ok, I'm well aware from the many posts I've read on here, that the mid 90's Z's seem to be prone to driveshaft related vibrations, noticeable mostly at high vehicle speeds. I see a lot of guys swapping to different driveshafts.
After I had my 95 for a few weeks I took the driveshaft & differential to what I believe to be a reputable shop. They replaced both DS U-joints, spun it up & balanced it & rebuilt the diff to OEM specs (just "consumables" replacements, like making sure everything was shimmed to spec & that the gear tolerances were good)
After that the vibration was about half what it was before, so I've lived with it since then. My question is, if I want to eliminate the vibration, what actions should I take next? I'm guessing the source is most likely a sloppy tranny tailshaft bearing, anyone support that idea? Is it possible/feasible to tighten up a tranny tailshaft without pulling the tranny? I would have thought the shop would have caught a problem with the diff input shaft, so I'm inclined to look at the forward end....
TIA,
Ian

 

It could be that bushing, but it could still be your vibeshaft as well..

I had mine balanced at a reputable shop, and it got marginally better...

I then called one of the premiere DS builders in the US (Denny's Driveshaft here in B'Lo NY) and talked with him for probably 1/2 hour about my situation.. very cool and knowledgable guy...

Basically GM designed the worst DS they could for our cars, the LS1 shafts aren't any better...

He stated that he was lucky if he could get them to balance to 7K rpms, and typical was ~6K. He gets the ones that he builds/sells to 10K with no problems... I've actually got one of his shafts on order now, because I have spent over 1.5 years and close to $5K trying to figure out my vibration...


The easiest way to check for the bushing is to see if the front DS yoke has any slop in it when it is installed, if there is some slop then the bushing is crap and needs to be replaced.

 

Good info thanks man!

Maybe I'll revisit the driveshaft issue (once I eliminate the tranny tailshaft bearing).

Anyone wanna reccomend a good aftermarket DS? Not looking to spend too much ya know....

 

Well... To add some more fuel to the fire.. I found out yesterday that my bushing/seal is shot as well...

I'm going to call Jason Cromer on Monday and see what he can do for me on a price, MSRP is ~$40 per GMpartsdirect.com.

It looks to be able to be repaced while still on the car with a slide-hammer and a pair of crow's feet pullers. We'll see how that goes when I get the parts in, I'm going to swap that when I get the new DS to put in.

As for driveshafts, I'd start out by finding out how fast your place balanced yours, then if you can go without your car for a week or 2 (some people use them as daily drivers, I don't know if you are one of them) send you DS to either Denny's Driveshafts, or Dynotech for Balancing.

Dynotech does a good turn-around and I've heard good things about their products.

Denny's does some GREAT work, but due to that fact, he's got about a 2 week backup just for balancing.