ls1247

iTrader: (2)

Like the title says, for those of you with 8.8 conversions, who's is smooth and who's isn't.

Let us know what kind of driveshaft, motor and transmission mounts you have.

Myself, I've got an 05 with the complete 8.8 kit, CS cradle and motor mounts and a window welded stock transmission mount. I've got a 1 piece carbon shaft and I have vibes from say 100 and up.

I've installed shims under the front cradle mounts to change the pinion angle and the vibes were reduced and pushed up the mph scale but they're still there. The driveshaft is a major pain to install because it appears to me it is too long. The cradle is currently shimmed almost a 1/4 of an inch and I don't feel comfortable going any further and I frankly don't like having shims at all.

My car has 258k on it so possibly I have a transmission issue but it would be nice to know if anyone is successfully using this combination! It's time to start spending money on the car so I need to know a little more about what my options are....stay with the 8.8 or do a V2 cradle swap.

Thanks

Anthony Toal

Full 8.8 kit, 1 pc aluminum. Had vibes around 75, changed out motor and tranny mounts with CS, vibes are now around 80

ls1247

iTrader: (2)

I'm guessing you have a DSS driveshaft. Did you have to force it into the car or stretch it too bolt it in or did it fit right..

I've had 2 DSS shafts and the one I have now I have to compress the CVs to get it bolted in and the other was too short and I had to extend the CVs to bolt it in...

Anthony Toal

I do, I couldnt compress it enough to slide it in without having to drop the diff and the trans down to fit it in. It isnt compressed all the way nor stretched. I fit right in the middle with their tolerances at 5.5". I have tried turning the shaft and that has made no difference and it is speed related, not rpm so I know it is behind me, my next guess would be one of the axles. the driver side was a tight fit for clearance and has me concerned some.

ls1247

iTrader: (2)

I acquired my 8.8 already assembled through a cradle swap so I really don't have a feel for how the axles fit. Mine vibed at 80 to 85 before I shimmed the cradle. Shimming the cradle down in the front with 2 cradle bolt washers moved the vibes well up the mph range to a little over a 100 and they aren't as bad either.

That kinda rules the axles and transmission out in my mind.

Part of me thinks this happened because it changed the pinion angle, another part of me thinks I effectively lengthened the driveshaft slightly by nosing the pinion down and it unloaded the CVs a little which is letting them work better....

But as my 05 had 258k and is an ls6 car, I bought an 06 yesterday with half the miles for 9k on a salvage title in overall excellent shape. Now the questions is, do I swap out the 8.8 kit or let it go with the 05 and do a V2 cradle swap on the 06.

I could have sworn some have had good luck with the 8.8 kit but is it would be nice to confirm that.

ls1247

iTrader: (2)

So this was referenced in regards to 8.8 vibrations by CS over on the other forum.

http://www.cadillacforums.com/forums...-8-8-a-26.html

If you read the post on page 26, they also refer to a DSS Carbon one piece being avaliable. Unfortunately, there were no reviews of it in that thread other than CS's.

Anthony Toal

Well talking with Maxx at CS, he said that the CF has more success than the AL, what they believe is with the large diameter shaft, the mass and rotation is hard to balance compared to the smaller CF or stock shaft. I think by changing the pinion angle your only changing the characteristics of the vibes themselves. Looking at NAFs post about the actually angle, his -2 can be a problem for us 1 pc users, although I am curious what that angle is with the 8.8, it could be worse. When I get my car up and running (hopefully this Friday) I will see where my vibes at, I want to start at the transmission and see if the changes or worsens it. I think everyone is going to have a different issue, but this is a first for me dealing with a drive line like this, so I can only share my experience

ls1247

iTrader: (2)

One of the challenges I have is actually getting a good angle reading off the shaft. The CF has a rough texture and I've tried using a straight edge but it doesn't take but the slightest variations to throw them the angle off....

but im also concerned about having to "load" the CVs to get the shaft in the car. That's gotta restrict them and keep the from floating. And I know that my changing the pinion angle, I've geometrically changed the affective length of the shaft which, although slight, might have unloaded the CVs.

does your shaft have 2 CVs or 1 unjoint and 1 CV?

Anthony Toal

1 U and 1 CV

NIKDSC5

iTrader: (10)

No vibes here ahahahaha

UMI mm
CS trans mount
1 piece DSS carbon fiber.
CS 8.8 brackets.
Upgraded axels.
Self built diff
Tru trac
3.73
CS diff block
Urethane front diff bushings
Stock rear diff bushings (115k)
DPW cover

And I think that's about it as it relates to potential areas of alignment/vibrations.

Anthony Toal

is it possible the diff block is isolating the vibes? or even absorbing?

barrok69

I had vibrations initially but then called DSS and I clocked my driveshaft 90degrees and it resolved the vibration.

I'm currently running:
CS Motor Mounts
CS Trans Mount
DSS Stock Length 1 piece Carbon Fiber DS. (U-joint -Trans, CV -Diff)
DS to Stock Diff adapter
"Shorter" Stock DS to 8.8 adapter (Yes I'm using two adapters, I didn't want to buy a new DS)
CS 8.8 Brackets.
DSS 1K HP Upgraded Axles
Ford Aluminum Trak Loc 3.73
LPW Diff Cover
CS Diff block
CS Front 8.8 Diff Bushings
Stock rear Diff bushings (50k miles)
CS Cradle Bushings
CS Spherical Trailing Arms
CS Trailing Arm Bushings (knuckle end)
CS Toe Rods (non-spherical)

I didn't do Any alignment.

ls1247

iTrader: (2)

Thanks for updating us guys!

BudRacing

iTrader: (3)

One thing I noticed about Nik's build is that he has a TDP stage 2 trans.

Barrok, isn't your car low-mileage?

barrok69

Yep 50k miles. Stock trans, clutch and stock pinned engine balancer.

TorchRedRob

iTrader: (1)

Similar list to barrok69 with no vibes (different shaft setup, though):

CS Motor Mounts
CS Trans Mount
DSS 2-piece steel / aluminum DS. (U-joint both ends, support bearing in stock location)
CS 8.8 Brackets.
DSS 1K HP Upgraded Axles
Self-built Ford Aluminum Trak Loc 3.55
LPW Diff Cover
CS Front 8.8 Diff Bushings
Stock rear Diff bushings (90k miles) ...still have new green revshifts in a bag- couldn't muster the energy to deal with them when I was in there...
CS Cradle Bushings
CS Spherical Trailing Arms
CS Trailing Arm Bushings (knuckle end)
CS Toe Rods (non-spherical)

ls1247

iTrader: (2)

So it looks like some of us are running the CF 1 piece with the U-joint on the transmission end and others of us, me that is, are running the u-joint at the diff end...

I might try flipping mine and see what happens.

Nik, you remember which end you're running your u-joint on?

Anthony Toal

That is one I got done as well and from I have been told by Jason, 6th gear can be the cause of the vibes as well. I am not sure by switching to a 1 pc that the harmonics are felt more. I will find out here tomorrow if I made things better or worse

Sssnake

No vibes now up through at least 120 mph (had vibes initially then went with shorter adapter, went back to stock tranny mount, and had rear tires re-balanced - all seemed to help). I do have an annoying decel whine.

Revshift Blue mm
stock trans mount
2 piece stock with VooDoo carrier upgrade
CS built 8.8"
3.55 gears
upgraded outer CVs
CS diff block
Urethane diff bushings (CS Kit)

BudRacing

iTrader: (3)

I'm definitely interested in your findings. The common denominator I'm finding, in addition to approximate speed of 80mph, is that those with high mileage on their transmissions are feeling it the most. No matter what other suspect parts are thrown at it (at much expense), the trans is the source of the vibes. Only those who have had their transmission rebuilt have said their vibrations were fixed. This is also found across different platforms with the T56.