Cadillac CTS-V - Anyone experience a clunk with their CS 8.8 kit??

Hey fellas,
Anyone here running the CS 8.8 still dealing with a clunk? My car still has that driveline slop and im not sure why. My buddy who had the car before me installed the 8.8. I know he got his own diff to save some money but obviously ordered the coated brackets, axels, eatin tru-trac, 4.10, etc all from creative steel. His stepdad is a gm mechanic so they did all the wrench work. The rear of the diff with that bracket doesn't look like it would move. Only thing I'm seeing that could be causing the clunk are the two bushings in the front of the diff. He left them stock because max at creative steel said if they look good, don't replace em because they rarely wear out. I'm thinking this could be my issue though.

Anyone else experience this clunk?

I'm considering ordering some poly or solid aluminum bushings for the 03 cobra which would obviously fit this diff. They offer both for it. Anyone else replaced the front two bushing on ur 8.8 with some aftermarket ones? Any input?

I'd go poly over solid for sure. What's the rest of your driveline like?

DSS driveshaft ?

I have the poly bushings. I have a clunk. Not sure if it's the driveshaft or play in the ring and pinion

I think the kit really needs a poly coupler from the transmission output to the driveshaft.. You need some give.

Mine has ton of slop... Max initially told me its normal for the TrueTrac carrier... I'm waiting to hear back from him to see if it's adjustable

What kind of locker or limited slip do you have? I have an eaton true-trac in my 9" and i can spin the pinion/driveshaft anout a 1/4 turn before the helical gears in the locker grab. It is highly annoying.

My driveshaft is stock. Used an adaptor that worked nicely for the time being since the carrier bearing was still good. I'm waiting for a solid driveshaft to come out cause I'd like to get away from the two piece if possible.

Locker is whatever is included with the CS kit. Everything came from them new other than the diff casing itself. Pretty sure it's the eaton tru-trac 31 spline locker like yours since that's what they advertise is included on the CS website. Maybe the slop is in the locker then if yours does the same thing. My stock rubber diff bushings honestly look to be in good shape. Everything looks tight but I get a lot of slack in the driveline. Its annoying as hell but I've learned to drive around it for the most part. I'd still like to fix it though if there is a solution.

I have a stock carrier, used differential with 50k on it. Factory gear lash on mustangs is usually on the loose side

What kind of locker or limited slip do you have? I have an eaton true-trac in my 9" and i can spin the pinion/driveshaft anout a 1/4 turn before the helical gears in the locker grab. It is highly annoying.

That's about what mine has too... About 75 degrees of free play.

Damn... So it's not the bushings at all. It's the actual carrier. That's depressing. Any way to snug it up?

Yea I was warned by Max that it is a noisy sumbitch... I didn't much care I'm just concerned about the lateral up and down play in the axles... Seals aren't leaking and the locker works like a champ, but will the excessive lash result in an axle snapping? I put in a message to Max on the Caddy forum

Yeah... Mine solid and clean with no issues. Just that annoying clunk. I'd like to get rid of it and like you... I don't wanna tear anything up because of it.

I have the CS 8.8 with a COBRA Diff and I have absolutely no clunk. I have the poly bushing on the diff also.

Well I guess the poly bushing is worth a shot then before I go doing anything more involved to fix it. What brand bushing are you running and where did u order it?

I got them from Summit Racing.

These are the ones:

http://www.summitracing.com/parts/PTP-6-1609/Application/?prefilter=1

I have the CS 8.8 with a COBRA Diff and I have absolutely no clunk. I have the poly bushing on the diff also.

If you have the clutch style carrier then you probably won't have this problem...

I have the CS 8.8 with a COBRA Diff and I have absolutely no clunk. I have the poly bushing on the diff also.

If you have the clutch style carrier then you probably won't have this problem...

Yep, Cobra clutched chunk and no clunk here either.

Thanks for the link to the bushings. I'll try those before anything else. If that doesn't fix it, I'll just deal with it. It's solid... Just annoying.

Prothane front diff bushings and new ford trac loc w/ carbon clutches. no slop or clunk in the drivetrain. sounds like a completely different car from stock. diff whine is gone, pinion lash is gone at low speed and while shifting, best mod i have done so far.

going catless and getting a street tune.. cant wait

I think the kit really needs a poly coupler from the transmission output to the driveshaft.. You need some give.

what would be the pros? the flex coupler would make the driveline more reliable?

Do a google search in manual trans with tru-trac or 6 speed with tru-trac. I asked over in the drivetrain section of this site and got many confirmations of how the tru-trac is far better suited for an auto trans and can get brittle with relatively low power level due to the slop and constant loading and unloading of the helical gears in there.

Simple way to check and save yourself from a potentially pointless bushing swap is to get under your car when parked, parking brake on or off it doesnt matter, just have the car in neutral and try to twist the driveshaft back and forth. This is assuming your driveshaft cv joint attatched to the pinion is in decent shape.

Well... Although most of my issue is probably in the tru-trac itself like all you others, i got a chance to look at the bushings while the car was on the lift today at the exhaust shop having the cutouts installed and the bushings all look pretty shitty. I'm sure changing those will fix some of the problem but hopefully all of it. Fingers crossed!!

Is there a complete kit for all the bushings on the 8.8 in poly that can be ordered or do you have to order them all separately?

Hey fellas,
Anyone here running the CS 8.8 still dealing with a clunk? My car still has that driveline slop and im not sure why. My buddy who had the car before me installed the 8.8. I know he got his own diff to save some money but obviously ordered the coated brackets, axels, eatin tru-trac, 4.10, etc all from creative steel. His stepdad is a gm mechanic so they did all the wrench work. The rear of the diff with that bracket doesn't look like it would move. Only thing I'm seeing that could be causing the clunk are the two bushings in the front of the diff. He left them stock because max at creative steel said if they look good, don't replace em because they rarely wear out. I'm thinking this could be my issue though.

Anyone else experience this clunk?

I'm considering ordering some poly or solid aluminum bushings for the 03 cobra which would obviously fit this diff. They offer both for it. Anyone else replaced the front two bushing on ur 8.8 with some aftermarket ones? Any input?

Front Poly Differential Bushings
Get the bushing from this guy.

http://supercoupeperformance.com/partBrowser.aspx?partId=189

I think I found my problem. My creative steel transmission mount seems to have turned into a sponge.

My tranny mount is stock and looks like shit. I bet between changing that and the diff bushings, my problem will be 90% if not 100% solved.

Only one way to find out...

I don't know but this clunkin/driveline slack bullshit is gettin old.

I don't know but this clunkin/driveline slack bullshit is gettin old.

Does it clunk when you go in reverse and when you change directions to go forward ?
Could be the DSS rear CV's loading when you change direction.

Mostly just between gears when moving forward. Just like the driveline is sloppy. If I let off the gas and get back on it, I feel it.

I think I found my problem. My creative steel transmission mount seems to have turned into a sponge.

I had the same thing happen to my CS trans mount.

Could a tranny mount cause this issue? Seems like more than a tranny mount to me but I guess it's worth swapping it to see.

Could a tranny mount cause this issue? Seems like more than a tranny mount to me but I guess it's worth swapping it to see.

Aren't you still using the stock driveshaft? Could it be that. Everyone that has chimed in, I believe have the DSS driveshaft.

Sounds like he has the TrueTrac carrier in which case that's the nature of the beast

I had the same thing happen to my CS trans mount.

interesting. I ended up taking the top plate from the CS mount, and welding a f body prothane mount to the plate. Drilled a hole in the crossmember. Much better now.:cool:

Yes I'm still running the stock drive shaft. Seems I'm not the only one that has experienced this clunk though. The trutrac carrier is the one creative steel sells with their kit. I couldn't imagine they'd sell something this sloppy for that price.

Call CS, depending on which diff you have this may be perfectly normal. I'm not going to try and remember everything they told me over the phone on the matter, but If I remember correctly the trac lock diffs will make noise. They will also hold up better at the track VS the standard cobra diff which is smoother but will not hold up as well with hard use. Like I said don't quote me on this but I believe this is the gist of what max told me.

That sounds the same as everything else I've heard about it so that sounds accurate to me. I was just keepin my fingers crossed and really hoping I could get rid of some of the slack somehow. The diff is stout... Just don't like that slop.

I guess I've gotten used to mine I think it's a matter of trusting it... I believe my kit is one of the last to have the TrueTrac before they switched to the Cobra carrier because of this reason

If its stronger... I'd rather deal with the clunk. Just annoying at times.

Let's not downplay the cobra carrier. It will take plenty of abuse. I don't think CS would switch to it if it couldn't. I'd rather have the quieter, no slop carrier, that's marginally weaker by not much than a sloppy, yet stronger carrier.

I'll take stronger

Me too especially since my car makes more than the average V. Getting tuned on the dyno again tomorrow. Should have a little better numbers to post this time.

I guess it depends on what your driving style is. I know for a fact I won't be clutch dumping every chance I get. That said I'll take "No Clunk and quieter, and much stronger than stock." Getting rid of the clunk was on the top of my list of why I went with the kit, so now I have the best of both worlds, instead of just stronger. To each his own though, but CS switching up says alot.

Yeah... Says they prob get the cobra carrier cheaper... :) lol

so what would be the pros of having a flex coupler instead of the beefy billet AL coupler between the t56 and driveshaft

I guess it depends on what your driving style is. I know for a fact I won't be clutch dumping every chance I get. That said I'll take "No Clunk and quieter, and much stronger than stock." Getting rid of the clunk was on the top of my list of why I went with the kit, so now I have the best of both worlds, instead of just stronger. To each his own though, but CS switching up says alot.

i agree 100%

Yes I'm still running the stock drive shaft.

How? I thought a new DSS driveshaft was mandatory??

How? I thought a new DSS driveshaft was mandatory??

I believe he only bought the brackets and pieced everything else together.

How? I thought a new DSS driveshaft was mandatory??

IIRC CS sells a stock DS to Ford 8.8 adapter.

That is correct. Works perfect. I'll get a nicer driveshaft when I find someone that makes a solid one piece shaft.

IIRC CS sells a stock DS to Ford 8.8 adapter.

That is correct. Works perfect. I'll get a nicer driveshaft when I find someone that makes a solid one piece shaft.

DAMN.. if i would of known that i would of just bought the DSS axles and CS brakets.. fukin ehhh.. nothing wrong with the DSS driveshaft, as far as noise or vibs, im just cheap

This thread is just making me more and more curious about the 8.8 UPS has on its way to me. I've got the cobra carrier, but still curious.

This thread is just making me more and more curious about the 8.8 UPS has on its way to me. I've got the cobra carrier, but still curious.

Curious about what ? Did you get the full kit with aluminum housing ?

I opted for the iron housing. Just curious to see how it drives, excited may be a better word. I'm just tired of listening to the car whine like an angry premadonna haha. I have no doubts that it will be a great improvement, but still just curious to drive it.

I opted for the iron housing. Just curious to see how it drives, excited may be a better word. I'm just tired of listening to the car whine like an angry premadonna haha. I have no doubts that it will be a great improvement, but still just curious to drive it.

When your ready to put it all in let me know. There are a few "tricks" to do it.

Has the DS and axles been shipped yet ?

This thread is just making me more and more curious about the 8.8 UPS has on its way to me. I've got the cobra carrier, but still curious.

I wouldn't worry too much... I don't think any of us make enough power to break the diff... You may have a few things to iron out, but it's a good kit. I was given the option between carriers... I chose Truetrac because I don't give a shit about a little noise I'm sure you'll be fine with the cobra carrier

I'll load vids of my car on the dyno today. They are on fb but not here yet. No worries with the CS diff. I got the whole kit with the exception of the driveshaft and it's holding fine so far. Oh... I'm iron diff too.

http://m.modernhemi.com/forums/showthread.php?t=1180194

Read through that. Will be contacting Gforce when i get back into the states for a wavetrac. True-trac on a manual car with decent power seems to be junk, mine is consistently getting looser and looser and my car pulls slightly to the left on launches at the track.

http://m.modernhemi.com/forums/showthread.php?t=1180194

Read through that. Will be contacting Gforce when i get back into the states for a wavetrac. True-trac on a manual car with decent power seems to be junk, mine is consistently getting looser and looser and my car pulls slightly to the left on launches at the track.

Apples to oranges, huh?

Mine launches and drives just fine other than annoying little bit of slop it has between shifts. If it breaks, the diff is iron so it wont be going anywhere. I'll just switch carriers and get a new ring and pinion at that time.

I wouldn't worry too much... I don't think any of us make enough power to break the diff... You may have a few things to iron out, but it's a good kit. I was given the option between carriers... I chose Truetrac because I don't give a shit about a little noise I'm sure you'll be fine with the cobra carrier

What is the cobra diff good til?

Is 800 rwhp out of the question for this kit?

My buddy is putting down 850 in his whipple cobra on stock cobra 8.8 and carrier with no problems. Runs slicks at the track and all.

This is why i highly doubt ill ever have an issue out of mine since its supposed to be a little stronger than even that one is.

Sweet....

Does CS offer the cobra diff?
Would need a lucky charm to find one up here.
I was just going to go with the Iron 4K setup they have....

Sweet....

Does CS offer the cobra diff?
Would need a lucky charm to find one up here.
I was just going to go with the Iron 4K setup they have....

Search Ford IRS in e-bay....650 is about the going rate. 3,73 gears are 50-150 bucks.

The aluminum 8.8 is what they run in the cobra but the aluminum and iron 8.8 diffs are identical. Aluminum weighs a little less and iron is a little stronger.

Found a few locally.

My buddy with my old car found an aluminum 8.8 diff for $150 local and scooped it up. Pretty sure it's just the housing itself though.

What is the cobra diff good til?

Is 800 rwhp out of the question for this kit?

I honestly don't know the limitation I chose the iron kit with Truetrac... I would think an axle would break before the diff. Seems like its somewhat of a pissing contest between the different carriers when in fact none of us are making huge numbers to compare... Lol all fun and games to me

My buddy with my old car found an aluminum 8.8 diff for $150 local and scooped it up. Pretty sure it's just the housing itself though.

I found the complete unbolted subrame for $200. I should really pick it up...

Apples to oranges, huh?

Did you actually click on the link before you posted this?

Yes Mary, but in a similar story I took my Maganavox TV to Europe and it would not plug in and work, so I stopped buying Magnavox TVs.

My point is that just because it does not work or is a bad product in a one application, does not mean that is true for ALL applications. (Not all Germans are Hilter if that is easier for you to understand.)

Take a look at some of the Clutch kits for the CTSV that MANY have had issues with, but work great in F-bodys.

Basically your rationale is wrong.

spanked a brand new 6sp 5.0 mustang last night.. in mexico. stoplight.. 3k launch. fell right back in love with V.. she squated spun um and hooked up took him 2 car lengths.. he had at least a cat back, prob stock tune but a win is a win on a 7 year old platform

I betcha he was PISSED and was wondering how you did it! lol Great kill.

I betcha he was PISSED and was wondering how you did it! lol Great kill.

haha, he wouldn't roll down his window at the next light :mullet:

Lol nice

Hmmm, I don't remember saying i would stop buying from Eaton, in fact im pretty sure I
said I was going with an Eaton Wavetrac.

Also not sure if your tracking that, much of the reason our cars have clutch issues is due to our nearly 2 ton curb weight.

I dont think its a big secret that the true-trac locker has a rough time holding its self together on a manual car with relatively mild power levels.

My car has a 9" rear by the way, which many Fbodys run.

Torque biasing diffs (True Trac, Quaife, Torsen), with their little gears in them, are not intended to be drag racing diffs.

You could say the same for our cars.

Nice shady! I rolled out on a pulley, intake, exhaust 03 cobra the other night on the freeway. Only got him by two lengths or so but his blower was whining its ass off in my passenger window as I was pulling away. Lol it was a white vert with a black top. Turns out after we ran, I was telling my other buddy about it and he knew who the guy was and what was done to his car. I was on motor... Didn't even have the bottle in the car. We went from about a 30-35 roll.

Anyway, as far as carriers go, is there another carrier that's just as strong with less slop? Just wondering if I should be looking into a carrier swap if these things don't like holding up to drag racing. Mines holding strong as of now though. Just has that little bit of annoying slop in it

You could say the same for our cars.
True enough! :lol:

Anyway, as far as carriers go, is there another carrier that's just as strong with less slop? Just wondering if I should be looking into a carrier swap if these things don't like holding up to drag racing. Mines holding strong as of now though. Just has that little bit of annoying slop in it
The OEM Ford Traction-Lok, Auburn Pro, Eaton Posi, or a good ol' locker or spool are more drag race friendly. (Those last two are probably way more hard core than most would want for a street car, though.)

Nice shady! I rolled out on a pulley, intake, exhaust 03 cobra the other night on the freeway. Only got him by two lengths or so but his blower was whining its ass off in my passenger window as I was pulling away. Lol it was a white vert with a black top. Turns out after we ran, I was telling my other buddy about it and he knew who the guy was and what was done to his car. I was on motor... Didn't even have the bottle in the car. We went from about a 30-35 roll.

Anyway, as far as carriers go, is there another carrier that's just as strong with less slop? Just wondering if I should be looking into a carrier swap if these things don't like holding up to drag racing. Mines holding strong as of now though. Just has that little bit of annoying slop in it

hahaha niiiiiccccceee..i love cobras,. my buddy in nj has a 03 cobra with a smaller pulley and 4.10 gear... bitch is insane!!! i can keep up in 2nd gear for a little but get ran on after that

imo beat the shit out the carrier that you have.. the stock trac lock is perfect for what it is.. if the tru trac goes in 25k rebuild it for 250-300$ and your good to go.. cant do that with the stock getcrap

Me too man! Was eye ballin it before he even pulled up to play. Lol I miss my 03 everyday. I love the V but that blower whine was so refreshing! Haha they run STRONG with just a few mods.

That's a good point bro. I think I'll do just that! Lol

Nice shady! I rolled out on a pulley, intake, exhaust 03 cobra the other night on the freeway. Only got him by two lengths or so but his blower was whining its ass off in my passenger window as I was pulling away. Lol it was a white vert with a black top. Turns out after we ran, I was telling my other buddy about it and he knew who the guy was and what was done to his car. I was on motor... Didn't even have the bottle in the car. We went from about a 30-35 roll.

Anyway, as far as carriers go, is there another carrier that's just as strong with less slop? Just wondering if I should be looking into a carrier swap if these things don't like holding up to drag racing. Mines holding strong as of now though. Just has that little bit of annoying slop in it

Nice! There was a local guy that had some year cobra, but I think he was stock. I used to beat his all the time in my 92 B4C. Anytime he saw me, he would chase me down and want to run. He hated me.

if the tru trac goes in 25k rebuild it for 250-300$ and your good to go.. cant do that with the stock getcrap

Can I repair the Truetrac if I need to?
The worm gears inside a Trutrac are maintenance free, and do not require regular service. Internal failure usually results in the damage of the worm gear pockets. Therefore, they are not rebuildable.


^^^^^Copied from the FAQ of Eaton's website^^^^^

54... That's funny. Lol I had a similar situation. I used to regularly see this black camaro SS on my way into work almost every morning. We were always both going the same direction at the same time. We'd do the same thing. Nothing better than a good morning run to start the day. :)

Cole... I hope it's repairable. I'll look into what I'll need to spend on a new one though if this one can't be fixed. Not that I'll be breaking it soon or anything but it's good info to know.

I spent alot of time on the phone with Strange Engineering (who sold me the diff) and Eaton. From what it sounds like, the play in the worm gears is the nature of the beast, which is why they are better suited for an automatic car. I doubt you have anything wrong with yours.

If you can live with it then run it until something happens to it, just know that the shock the worm gears are experiencing almost every shift is not friendly to them, especially at your power levels and curb weight. Another thing to take into consideration is that if indeed it does let go (not saying it will), you could potentially destroy your ring and pinion, bearings etc...

I for one cannot live with it, the constant clunking.. it drives me nuts because it feels like the stock rear did and, weather i like to or not im adjusting how I drive my car in order to avoid it.

Yeah... Nothing is wrong as of now. Just sounds like some usual slop as expected. Let me know what you decide to do and what carrier you go with. If its strong and doesn't clunk or have any of this slop in it, I may consider switching. I mean I may never have an issue with this current carrier but if I can get a replacement for a decent price that will get rid of that slop and sell mine, i may go that route.

Anyway, as far as carriers go, is there another carrier that's just as strong with less slop?
The OEM Ford Cobra Trac-Loc. It is the same unit that comes standard in the 2013 Gt500 with it's insane HP and torque output. Too much ring gear backlash and a loss of pinion preload will also cause the clunk. However, in your case my money is on the True trac.

The video below shows the slack experienced with a Wavetrac which is the same design issue with the True Trac.

http://www.youtube.com/watch?v=pXGDCPU0NSg

Thanks for posting that vid! That is exactly what the problem is. Makes me feel better than everything else is tight though. Its just annoying to feel it between shifts at times...

Thanks for posting that vid! That is exactly what the problem is. Makes me feel better than everything else is tight though. Its just annoying to feel it between shifts at times...

You can tune having to "drive " around the clunk out. There are plenty of throttle airflow tables that can be increased to get rid of that

How would the tuning change having to clutch for every gear? When the clutch is engaged, the pressure will be released and when it's disengaged, it'll clunk. I don't see any way around that...

tune the clunk out?

Thanks for posting that vid! That is exactly what the problem is. Makes me feel better than everything else is tight though. Its just annoying to feel it between shifts at times...
I'm sure it's annoying. I've read some Cobra folks have had success with Redline shock proof. Apparently it does quieten the true trac some.

Do u still need to put that friction modifier stuff in with the gear oil?

Do u still need to put that friction modifier stuff in with the gear oil?
No. The True trac and other gear type differentials do not require friction modifier.

If you adjust the rate that the throttle body adds air as you apply throttle, you can "soften" the transition. Just like when you are in a gear, let go of the throttle in gear fast. Some cars will instantly decel, some will gradually decel. Its all in the airflow tables.

Oh I see. Well that make sense. I would think that might work on an auto car that stays constantly engaged but on a manual car, when u clutch it, it's not going to matter where the tb air table is. The driveline will lose tension when I shift and let the clutch back out, it will clunk.