Driveline Vibration

[eighty6gt]

How many seconds in the 1/4 do you get by ditching the stock driveshaft?

 

[AnotherS197GT]

Just bumping this back up... After a few weeks of driving, the vibe is mostly gone with the stock DS, but still lingers at high speeds. I'm getting a quote on a 3.73 install and I think I'll be swapping gears. I really like the punch the 4.10s pack, but the vibe is irritating when I want to put my foot, and I'm kind of tired of hanging at 2800 RPM driving to work.

 

[thump_rrr]

What app is that you're using?

After 4 rear ends including a Truetrac and a wavetrac I went to a 9" and couldn't be happier.
Buy once cry once.

 

[AutoXRacer]

After 4 rear ends including a Truetrac and a wavetrac I went to a 9" and couldn't be happier.
Buy once cry once.

Which one did you get? I want one...its my last mod. Was it completely bolt-on?

 

[AnotherS197GT]

What app is that you're using?

After 4 rear ends including a Truetrac and a wavetrac I went to a 9" and couldn't be happier.
Buy once cry once.

This is a CAI/tune street car. 9" is overkill to say the least lol. It's an iphone app called iAngleFinder. I like the Tremec app much better though.

 

[thump_rrr]

Which one did you get? I want one...its my last mod. Was it completely bolt-on?

I got the old banjo style Currie housing because JDM had one for sale here at a discount and I ordered thei Currie 35 spline axles with ABS rings and a set of their brackets to bolt the factory brakes on.
The only other thing required was a BMR panhard bar relocation bracket.

I ordered a Moser center section because I had a Wavetrac 8.8" which is a POS because of the clips that hold the axles in.
Moser is the USA/Canada distributor for Wavetrac and they gave me a full $995.00 credit towards the new center section.
I went with a 9" wavetrac which doesn't have the retention issues the 8.8" does since the axles are held from the outside.

If I didn't have the credit I would have ordered the whole 9" from Currie already put together. Just add oil and bolt it in.

 

[thump_rrr]

This is a CAI/tune street car. 9" is overkill to say the least lol. It's an iphone app called iAngleFinder. I like the Tremec app much better though.

I know what you're saying but the first 2 times I did the diff I was N/A also.
The problem is you tell yourself that this will be the last time.
Next thing you know you break a pinion gear so you buy all new bearings again and you then add a Truetrac so there goes another $1100.
Then you go forced induction and blow that up and you're at the same place but this time you put a $1000 Wavetrac in plus all the other parts and you just spent more than the whole 9" setup.

 

[AutoXRacer]

I know what you're saying but the first 2 times I did the diff I was N/A also.
The problem is you tell yourself that this will be the last time.
Next thing you know you break a pinion gear so you buy all new bearings again and you then add a Truetrac so there goes another $1100.
Then you go forced induction and blow that up and you're at the same place but this time you put a $1000 Wavetrac in plus all the other parts and you just spent more than the whole 9" setup.

The whole 9" rear setup is not expensive at all when you consider the cost of a T-56M XL, blower/turb setup, etc...

You can pick up a whole bolt-on ready 9" from Moser and Strange for a little over $2,000; a bolt-on ready for 05-14.

 

[eighty6gt]

I thought they were more like $3000? The differential alone will be 8-900.

It's a bargain either way. I really don't like the 8.8 that much.

 

[thump_rrr]

The whole 9" rear setup is not expensive at all when you consider the cost of a T-56M XL, blower/turb setup, etc...

You can pick up a whole bolt-on ready 9" from Moser and Strange for a little over $2,000; a bolt-on ready for 05-14.

You'll be a lot more than $2000 with a limited slip in a 9 inch.
My pumpkin alone cost $2200.
It was another $700 for the axles with the brake backing plates and the oil.
And it was another 750 for the bare housing.

There have been fitment issues with the Mozer reruns several guys on the forums have tried it and it did not like it.
Born to run returned his Moser 9" and was charged a 15% restocking fee.

The problem with the strange 9" is that they are narrowed.

 

[AnotherS197GT]

I know what you're saying but the first 2 times I did the diff I was N/A also.
The problem is you tell yourself that this will be the last time.
Next thing you know you break a pinion gear so you buy all new bearings again and you then add a Truetrac so there goes another $1100.
Then you go forced induction and blow that up and you're at the same place but this time you put a $1000 Wavetrac in plus all the other parts and you just spent more than the whole 9" setup.

I also don't have a bunch of cash for a 9". I'll do the gear and if this car manages to survive the next few years, I might consider one if and when I build it up. For now its staying with an 8.8.

 

[DiMora]

I've got a solid spacer in there already, and I just drive it on the street with street tires.

I did some more driving today and it seems that the vibration has moved itself to 90+. I'm not sure if I should bother having the rear end taken apart and the gear done again. With my luck it will come back 10x worse. Maybe I'll just trade it in for a 5.0


I really think that its a gear issue and the DS amplified the problem being that it takes up more slop. Unfortunately, I think I will be selling the 1 piece and sticking with the clunky shitty stock DS.


I have been emailing back and forth all day with Coast, and I'm very impressed with their level of service. I came right out and told them I bought the DS second hand and I want to check the balance, and asked for a price. He's been asking me questions all day about my driveline angles instead of just throwing a number out there.

That Coast driveshaft is perfect. I ran it on my car at triple-digit speeds and it was smooth like butter. The problem you are having lies somewhere other than the driveshaft. If you had vibrations before the DS went in, it is clearly not the DS.

 

[AnotherS197GT]

I definitely agree with you. I tossed the stock back on and it definitely cleaned it up a bit though. It masks the vibes a lot better since it's so squishy.

 

[Yuslowgt]

I am having the same problem after 90mph+ I get a vibration. I just purchased the car at a dealer it's a 07 gt 5 speed. I noticed it has rear lower control arms, paftermarket pan hard bar , aftermarket swaybar, aftermarket and links, they all have polyurethane bushings. And I'm guessing it has gears because my miles per hour gauge is off by like 15 to 20 mph. And it's lowered. Anyone find the reason? Btw just check I have stock 2 piece driveshaft

 

[AutoXRacer]

I am having the same problem after 90mph+ I get a vibration. I just purchased the car at a dealer it's a 07 gt 5 speed. I noticed it has rear lower control arms, paftermarket pan hard bar , aftermarket swaybar, aftermarket and links, they all have polyurethane bushings. And I'm guessing it has gears because my miles per hour gauge is off by like 15 to 20 mph. And it's lowered. Anyone find the reason? Btw just check I have stock 2 piece driveshaft

You should not be getting vibrations if you have the stock driveshaft unless, you are lowered very low and your pinion angle is off. Thats where I would start.

 

[Yuslowgt]

You should not be getting vibrations if you have the stock driveshaft unless, you are lowered very low and your pinion angle is off. Thats where I would start.

It's pretty low. Not slammed.

 

[07 Boss]

Maybe this is a shot in the dark but seems like it might be worth mentioning. I don't have currently have any vibration and once had an unbalanced 1-piece that ended up with the bad slide thingy too, but that's not where I'm going. I do remember a long time ago I pulled a couple of useless pieces of metal bolted to my axle. If I remember correctly they were there as vibration dampners of some sort. I had to pull them off to install something like relocation brackets or something. I'm just wondering if maybe swapping gears induced a frequency that maybe these things were supposed to dampen. Does anyone know what I'm talking about? Do you guys have these dampners still attached to your axle?