Is this what fails?

[Haitian_King]

Is this the thing that fails/wears out on the driveshaft and causes the vibrations?Is it possible to just buy the replacement part or is it best to remove the entire shaft? I just got a very good deal on a '92 driveshaft, but I'm wondering if it's worthwhile. If that's the part that wears out before the design was changed for 94, would it just be best to just get a later driveshaft? Can that thing be replaced on my current driveshaft, or should I just take it out?

Is this a DIY type of thing? Or is it a shop job?

[Q45tech]

The problem is how to disassemble the two piece driveshaft and maintain or rebalance to spec.Foam is used inside the shaft to stablize the actual driven core, eventually gravity and rotation takes its toll and the shaft should just be replaced.

Even the improved 94 just prolongs the eventual demise instead of 100k life the new one goes 150-200k.

When things are only designed to last [stay in spec] for 100k you get to rebuild and rebuild.

The problem is/was that the shaft had to be able to survive ~~ 6900 rpm [1:1 in 3rd gear] very few lux cars had that high of a limit.

My 2nd new shaft is approaching 200k and the telltale signs are starting and I had it on car strobe rebalanced at 100k, I try again but unlikely I can get it to hold for more than a year or two.

[96Qowner]

I'm getting a vibration in the 20mph range, no matter the gear. It feels like driveshaft - does that sound right? Any other likely culprits? It seems worse when it's really cold outside. At highway speeds it's gone.

[Haitian_King]

The problem is how to disassemble the two piece driveshaft and maintain or rebalance to spec.Foam is used inside the shaft to stablize the actual driven core, eventually gravity and rotation takes its toll and the shaft should just be replaced.

Even the improved 94 just prolongs the eventual demise instead of 100k life the new one goes 150-200k.

When things are only designed to last [stay in spec] for 100k you get to rebuild and rebuild.

The problem is/was that the shaft had to be able to survive ~~ 6900 rpm [1:1 in 3rd gear] very few lux cars had that high of a limit.

My 2nd new shaft is approaching 200k and the telltale signs are starting and I had it on car strobe rebalanced at 100k, I try again but unlikely I can get it to hold for more than a year or two.

So, a shaft from a 92 with 10k (I think) would be just fine and last problem free for the next 90k?

So I can't replace the shaft in the driveway then right?

[Kiven422]

So its the driveshaft causing all the vibrations?

In my 93 its pretty noticable unless i play tricks with the gas.The 94 does it occasionally... usually depends on how i am on the gas

Is a DIY replacement tough?

[Haitian_King]

Keith Van Meter told me that it was a common replacement item when he worked at the dealership. He said it was covered by warranty back then so he never thought twice about ordering 3 or 4 at a time. From what I've read, the vibrations come from worn driveshaft bearings and worn transmission mounts.

[lino]

Check out this thread:

zerothread?id=201042

and this one:

zer...32006

[Haitian_King]

Thanks lino. These are the threads I had read and learned about the driveshaft issue. Will a worn driveshaft result in less than optimal transmission performance?

[lino]

I think so. My car shudders once it hits around 45mph while going up an incline. I usually have to let off then back on the gas to get it to stop. It's quite the balancing act. It has gotten worse this year. Before it would happen only in one particular place and now it happens more often and in more places. I pretty much know when and where it will happen. The shudder makes the steering wheel shake pretty bad. I think in my case it happens when I let off the gas and then back on while going up an incline.

[Haitian_King]

That describes exactly what my problem is. Sometimes it seems that the shaft will seat properly and I have no issues. Other times, first gear will shift to 2nd by 2 or 2.5k RPM's with a hard jerk. I'll be at >20 MPH. Then when it's behaving, I'm able to watch the RPM's go to 4k before it shifts. In both cases, my pressure on the throttle is the same. I don't floor it. Hopefully the shaft replacement will get rid of this.

[Kiven422]

The shudder makes the steering wheel shake pretty bad. I think in my case it happens when I let off the gas and then back on while going up an incline.

Okay so the steering wheel shakes for you too... 2 weeks ago my car was smooth as a rock then I did an oil change and the absolute first drive after that was when it started... whats up with that!

[T45]

Carrier bearing failure is one of nissan's biggest flaws. Yeah it's great when it is new but they fail a lot and they're pretty expensive to replace.

A lot of truck and car guys just install a one piece to eliminate it alltogether. If nobody makes one for the Q you can just find a local driveshaft shop and they can make one for you from your stock 2 peice. Most charge under $200 for this and they can be dynamically balanced just as good as OEM. A good one piece will drive just as smoothly as a 2 piece.

As an added bonus you'll probably lose 15lbs in rotating mass from the drivetrain. That can mean a little more acceleration, stiffer launches and better economy. Add a good electric fan for another 10-12 hp and some good synthetic lubricants to the trans and rear end and you'll have a much more efficient drivetrain gaining you acceleration and fuel economy.

[Haitian_King]

Is that right? I was just going to replace the entire shaft.

Hmmm. For under $200 you say? Something I need to look into. Now, by driveshaft shop, did that include transmission shops? I keep passing one called Mr. Transmission.