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Hey I put in a 8.8 kit last year that I bought used off a member on here. It's got the one piece aluminum driveshaft with on u-joint in the rear and a cv at the front.
I have a vibration that is more like a buzzing at 140 km/h it's really bad. At 100km/h I can just start to feel it. It's not the typical driveline vibration where it pulses. It's a buzzing vibration and with the clutch in or out, on power or off its the same.
No it only started when I installed it at the end of last summer. Was parked all winter. Finished my ls3 swap with new motor and transmission mounts and still does it.
You sure the diff was set up properly?
I have a light vibration on my 8.8 but I have a 2 piece. Went to a local drive shaft shop. They checked out my drivrshaft and said.it was perfectly balanced. Ended up my diff gears where not set to the proper tolerances.
Originally Posted by BlackSS/SC
No it
only started when I installed it at the enwashet summer. Was parked all winter. Finished my ls3 swap with new motor and transmission mounts and still does it.
That's a possibility but they don't howl at all and it's great until over 55mph. I've seen and heard what wrong gear setup sounds like and this isn't it. I work at a garage and we do gears here. This is a very violent buzzing that makes the dash sound like it's going to fall off.
The previous owner never had a vibration supposedly.
That's a possibility but they don't howl at all and it's great until over 55mph. I've seen and heard what wrong gear setup sounds like and this isn't it. I work at a garage and we do gears here. This is a very violent buzzing that makes the dash sound like it's going to fall off.
The previous owner never had a vibration supposedly.
That's a possibility but they don't howl at all and it's great until over 55mph. I've seen and heard what wrong gear setup sounds like and this isn't it. I work at a garage and we do gears here. This is a very violent buzzing that makes the dash sound like it's going to fall off.
The previous owner never had a vibration supposedly.
Also did you try the speed in different gears 4 5 and 6?
I did reinstall the shaft different than before when I put it back in and it did seem to help some. The gear it's in doesn't matter. Clutch in or out its the same. A constant buzz, not a pulsating buzz like a bad u-joint or driveshaft angle. I rebuilt the transmission last year too but it only started as soon as I put the 8.8 in.
check your angles between trans and diff... I suspect its the driveshaft and or driveline misalignments that your fighting.. I have seen a few with similar problems
Look into motor mount sag and tranny mount sag as well... some have changed mounts as well as shim.
Does anyone know the optimal angles? The u-joint at the diff pretty much has no angle at all. A small angle at the cv. Can measure and shim but what should I be shooting for?
I have a very similar issue with a CF driveshaft. Same deal, U joint at one end and CV at the other. I have chased rotating the driveshaft, replacing the sagging trans bushing, shimmed trans mount ect. With each the vibration has changed(gotten better or worse) but I have yet to completely eliminate it. Everything I have read points to driveshaft angles. Currently it is comes on about 90-100 mph ramps up and then goes away at about 120. Been waiting for winter to end to start tweaking it again. Supposedly the CV should be able to counter whatever angle the U-joint is seeing, but I read that they have since done away with the U-joint for dual CV's.......
Does anyone know the optimal angles? The u-joint at the diff pretty much has no angle at all. A small angle at the cv. Can measure and shim but what should I be shooting for?
We don't have these angles because we never measured them off a brand new car to establish baselines and we've changed these angles with various combinations of motor and trans mounts.
The front half of the driveshaft needs to be at the same angle as the output shaft of the transmission. The best way to measure this as far as I can tell is to get a flat piece of steel, drill 3 holes in it that will allow you to bolt it to the transmission driveshaft flange, bolt it up, measure angle, reinstall driveshaft and either shim bearing or trans mount until these angles are the same. The reason you make the plate is to get a flat surface to work off of. The output flange isn't shaped friendly enough to get accurate angle readings off of IMHO.
I have UMIs in mine and I had to shim the driveshaft bearing down a half inch to even everything up.
The rear part of the shaft doesn't seem to matter from an alignment standpoint as having cvs on both ends of the shaft will allow the shaft to operate properly at different angles on either end.
The cvs went south on my carbon shaft and DSS gave me a full refund including shipping!
You sure the diff was set up properly?
I have a light vibration on my 8.8 but I have a 2 piece. Went to a local drive shaft shop. They checked out my drivrshaft and said.it was perfectly balanced. Ended up my diff gears where not set to the proper tolerances.
My previous post would obviously be how you align a 2 piece.
In theory, there is no alignment required on a 1 piece with a ujoint on one end and a cv on the other. The cv should be able to compensate for any angular differences between the 2 ends of the shaft and work in unison with the ujoint no matter what the angles are.
This is however theory as explained to me by Frank at DSS. Wouldn't hurt i guess to get the angles as close to each other as possible.
Keep in mind though that a ujoint has to operate at at least 1 degree of angle in order to work properly. The ujoint can not be straight or the needle bearings in it will flat spot because they aren't being forced to rotate.
I haven't done an aftermarket driveshaft before, but I have tested engines on engine dynos. In that situation, you setup the engine in such a manner as to make the U-joints/CV "work a little," i.e. at a slight misalignment between the engine centerline and the driveshaft centerline. You want there to be a small angle between the two. That way, the bearings in the U-joints don't sit at the same location all the time while transmitting the torque. Too much of an angle is not desirable, I believe because of vibration.
Is the theory behind setting up a car's driveshaft and the trans output shaft similar?
I had an issue with the bolt on the inner cv joint hitting the subframe. This happened because the front bushing for the 8.8 mount were backwards. Had the larger (thicker bushings) on top and shorter on the bottom. Which is switch and should be the other way around. Energy suspension bushings. Caused a constant Vibration.
I had an issue with the bolt on the inner cv joint hitting the subframe. This happened because the front bushing for the 8.8 mount were backwards. Had the larger (thicker bushings) on top and shorter on the bottom. Which is switch and should be the other way around. Energy suspension bushings. Caused a constant Vibration.
Whoa! Not knowing the details about the 8.8, this makes a bunch of sense. Could it be this simple?
My 8.8" has made noise from the jump. I have done everything I know to quiet it down including dropping it and re-installing it a few times. The bushings I have on the front seem to be the same thickness. See below. Are yours different? IF so, do you have a pic? I would like to be able to go back to Max (who has been very helpful) with something concrete.
I'll try to mic them tonight to see if they are slightly different thicknesses.
Is the theory behind setting up a car's driveshaft and the trans output shaft similar?
The factory 2 piece has no joints at all on the front part of it. That's why they put the flex disc in it, to help compensate for SLIGHT misalignments.
If the trans and the driveshaft on our factory driveshafts aren't working together in a straight line, it'll be vibration city in theory.
Also have seen reports that as the factory flex disc gets old, it gets hard and therefore doesn't flex that well. Heard where replacing an otherwise good looking flex disc with a newer softer one has cured vibs for some. Based on that, I'll be replacing mine with a new Camaro unit at some point.
Op, email frank at DSS, he has been very helpful. Do a search and you can pm him from here.
04-20-2015, 03:38 PM
8.8 rear end vibration 
