Anyone with a 1 piece driveshaft? D I have a problem or is this normal?

[Jonb42]

Just to give a quick overview of my ? Or problem. I have a 99 gs with. 2jzgte vvti IPT race built trans. T67 single trd lsd rear diff lowered with d2 coilovers megan rear lover control arms toe arms and traction rods. I have poly diff mounts and poly upper rear control arm bushings. I have a 1 piece driveshaft with forged isolater couplings attaching it to the flange on the trans and the diff. All this work was done at the same time when we swapped the motor from my old gs (crashed) to this one. The problem I have which I'm not sure is a problem or if its a semi normal thing to have with a solid driveshaft Is on the highway doing between 80 and 90-95 there is a vibrating sound similar to a wheel bearing sound but not as intense. It's a low pitched rumble. I'm wondering if there is a problem or if anyone else has experienced a similar issue. I like the idea of never having to replace the rubber isolators. Before I go through that headache of buying new rubber isolators (the one ones I have are cracking) and swapping in my old driveshaft to see if the problem stops I was hoping for someone to tell me it's normal. I don't cruise between 80 and 95 anyway. I either blow through that speed range or am not in it at all so it doesn't bother me besides the fact that idk 100% if the driveshaft is the problem. Thanks for the input if any.

[dnegative]

No

Sure its not diff/wheel/tyre/bearing related?

[George]

I have single piece shaft and experience the same problem. In my case, it's unmatched in|out angles and the use of U-joints instead of CV joints but I don't have enough time now to fix it. In general, it can also be unbalanced and/or unaligned (off-center) shaft.

Any shaft has a number its own resonance frequencies; you hear vibration if shaft's angular speed corresponds to any of these frequencies, and the frequency itself is within audible range.

some further reading:
http://www.classicchevy5speed.com/fi...roc_111606.pdf
http://www.markwilliams.com/driveshafttech.aspx

[LittleRedSpirit]

One piece shafts are in general more suitable for lower cars for this reason.

[Jonb42]

I thought it might have been the wheel bearings but the noise doesn't change when turning left and right. I'm pretty sure that wheel bearing noise would. The diff was just 100% rebuilt and all the bearings were changed so I know that's not it. The trans was rebuilt by IPT setup for full race but before I had the accident in my old car. Last night I had a rear seat passenger and I noticed that the noise didn't start till 85 or 90. George. I was wondering how I can change the alignment of the shaft? Is it possible. Thanks guys.

[Jonb42]

Sorry. Didn't read the links. Thanks for the info.

[Celica RA45]

does the car come out with a 2 peice tail shaft from factory .if it does then you need to go back to it .you have lowered the car and the diff angles will be wrong ,but a 2 peice will fix this problem

[Jonb42]

Yes. It does come with a two piece but I'm going to try raising the rear up a inch or a inch and a half. If that doesn't fix the problem then I will revert back to the factory d shaft.

[dnegative]

does the car come out with a 2 peice tail shaft from factory .if it does then you need to go back to it .you have lowered the car and the diff angles will be wrong ,but a 2 peice will fix this problem

If its IRS it doesn't matter how low/high you go, diff center is mounted to the body. It will fuck with your CV's but not overly.
Even if it was live, chances are the JWA will still be alright even if you lower the car a bit. Universal joints like some angle, they hate being dead straight.


A properly made single piece driveshaft shouldnt cause undue vibrations or noise, you will get a little but nothing like you have.

[Celica RA45]

since you have lowered it ,is it pushing on the center carrier at all .like pushing into the back of the gear box .just a thought

[Jonb42]

D you think that it could be a bad axle. This is the first rwd car that I have owned. I know what a fwd axle feels like when they go bad. I did get into a accident and hit the rear left corner of my car on a median. I know that the hub was slightly bent. Could it be possible that one of the cv joints is causing the vibration? Wat would the symptoms of a bad axle in a rwd car be and how can I tell if one is bad.

[George]

lift that wheel and see how it goes @90km/h. Make sure you don't alter car's ride height when jacking the wheel (i.e. put something under suspension arm)

[mullett]

There's a reason that the factory use 2 piece shafts: They're quieter/smoother etc. A GS is a very long car, so you'll need a BIG tube diam for a 1-piece shaft to keep resonance/vibration in check.

[Jonb42]

So I raised the car last night. About 1.5". I found one problem. The rear left wheel bearing is toast. I hope that that is the cause of the vibration but I have a question about the direction of the driveshaft mounting. I have a 3 bolt flange on the trans and diff so the driveshaft has the slip yoke built in. Do I put this in front behind the trans or in the rear by the diff? I'm wondering if its installed backwards! I have the slip portion in front by the trans. Anyway I have the bearings already. I just didn't have time to get that involved. I finished what I was doing at 4am. And it's such a pita to press the old bearings out I wouldn't have made it home today. Lol. Gonna go at it after a short break/nap. Or curiosity is gonna kill me. Lol hope everyone had a good weekend and thanks for the suggestions and help.

[George]

your setup is ok, slip part goes to the trans