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The Mighty Kael, 2004 Black CTS, Every Option
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Discussion Starter #1
so when the differential failes, what is the cause of the failure?

I hear several members here have had it happen, i want to know what was told or what was found out to be the cause.

does the V use the same Diff as us?
 

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Kael said:
so when the differential failes, what is the cause of the failure?

I hear several members here have had it happen, i want to know what was told or what was found out to be the cause.

does the V use the same Diff as us?
Coming out of seclusion for this one. NO ONE knows why a diff fails, or really how big a problem they really are?

A differential always makes SOME noise. I am someone who was wiened on rear wheel drive cars. There is a difference between fWD and RWD autos obviously, and I have a theory that with the CTS there are some people who buy this car and its literally their FIRST RWD car. Therefore they hear rear wheel whine and say WTF is that?

NOW, obviously a failed rear differential would make all kind of noises before it would seize up, or even possibly explode under load. How many of these supposed "failures" of a CTS differential is an actual failure and how many is just rear differential whine is anybody's guess?

There is no REAL data that tells us how many of these there are, what is causing it, and how big and how REAL a problem this is. Cadillac would be able to answer this question, but for obvious reasons they will keep it close to the vest. My guess is this, a differential failue would be a pretty serious occurance, serious enough to warrent a recall by GM, and we have't see that as yet, so my gess its NOT that big a deal or just not as serious as all that.

If GM ever does a recall, that would alert you to some manufacturing or design defect.
 

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jteolis said:
Coming out of seclusion for this one. NO ONE knows why a diff fails, or really how big a problem they really are?

A differential always makes SOME noise. I am someone who was wiened on rear wheel drive cars. There is a difference between fWD and RWD autos obviously, and I have a theory that with the CTS there are some people who buy this car and its literally their FIRST RWD car. Therefore they hear rear wheel whine and say WTF is that?

NOW, obviously a failed rear differential would make all kind of noises before it would seize up, or even possibly explode under load. How many of these supposed "failures" of a CTS differential is an actual failure and how many is just rear differential whine is anybody's guess?

There is no REAL data that tells us how many of these there are, what is causing it, and how big and how REAL a problem this is. Cadillac would be able to answer this question, but for obvious reasons they will keep it close to the vest. My guess is this, a differential failue would be a pretty serious occurance, serious enough to warrent a recall by GM, and we have't see that as yet, so my gess its NOT that big a deal or just not as serious as all that.

If GM ever does a recall, that would alert you to some manufacturing or design defect.
Speaking as one that has had one of three seize (the first merely howled - it was replaced before failing; the last is moaning now) at 45-50 mph, I disagree - it is a big deal - sliding sideways in traffic with a seized differential is an interesting time frame within which to reflect on same... May you and others never experience a similar trip...

I too grew up with rwd & still prefer it. Have driven hundreds of thousands of rwd miles, but have never owned a vehicle with a rear end that moans like this...

I have informed the national safety folks & Cadillac that I consider it serious enough to warrant a recall. Apparently a few folks need to bite the big one before they take matters seriously...
 

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jteolis said:
3 differential failures would trigger a lemmon law complaint no?
Yeah, I'd thought of that... Unfortunately the wife doesn't drive it much & I kinda overlooked the noise the few times I'd driven it over the first year... Then we took it on an extended trip - about 4500 miles. Drove me crazy & took it in when we got back home - they replaced it with one that failed on the way home from the shop. Unfortunately, this happened after we'd had the car about 18 months - our lemon law states that things have be be well underway within the first year...

I did get an extended nontransferable warranty dealing specifically with the differential out of GM - good to 100K or 10 years - like I'll keep it that long... I've been trying to find a sucker to buy it at a fair price, but no luck. Only 23K, miles that is... So..., we're using as a third car - local grocery shopping, very short trips, close to a tow truck. Plan to go in shortly & ask them to order our fourth differential - as long as we have it & the extended warranty, I plan to camp on their doorstop whenever the rearend sounds as though it's on the way out...

It does make a nice looking lawn ornament...
:D
 

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I edited this a bit for brevity but it is a good explanation of what's happening to the Cadillac differentials. Thank You Cadillac.:annoyed:

"What is the cause of this? A visual inspection of the differential case will more than likely (99%) of all cases will reflect cracking of the sand cast aluminum differential case caused by drive train deflection at the rear of the drive shaft tunnel. This deflection is usually around 4% which is enough to crack the case and cause the carrier gears to fail. I know this for a fact as I've cracked at least 6 cases and will actually this time post some photos of the various diffentials and where they crack.

The bottom line is that the differential case is constructed of sand cast aluminum and "hard launching", speed shifting, clutch dumping will grenade that rear-end.

What you need is a "permanent fix" if your hard launching this vehicle or exceeding as deflection is cracking the damn carrier case and eating your ring and pinion gears for lunch.

Your rear end is more than likely history or on it's way there. The dealership will replace it with a 2006 unit with deeper cooling fins, however that will NOT fix the problem as I've cracked one of those just recentley as well.
This is what you would call a "ROYAL GM SCREWING" by Cadillac as they were made aware of this issue by Getrag before selecting this sand-cast aluminum carrier case and it's high rate of failure probability.

regards - CMS, LTD."
 

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The Mighty Kael, 2004 Black CTS, Every Option
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Discussion Starter #8
yes robert, i read that post by cms ltd.

what i am wondering is if this is such a problem why dont we see more of it.
is the diff in the cts the same as the cts-V?

i have seen diff's fail from simple stupid things like a sloppy install, it only has to be off kilter by a couple of seconds (degrees, minute seconds) to cause failure.

if it was th case would it not leak all over the place? have they? these are the things i would like to know.

I am going to ask around a few otehr forums, i know the kitcar guys have an updated getrag differential so I will see what they can tell me.
 

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Kael said:
yes robert, i read that post by cms ltd.

what i am wondering is if this is such a problem why dont we see more of it.
is the diff in the cts the same as the cts-V?

i have seen diff's fail from simple stupid things like a sloppy install, it only has to be off kilter by a couple of seconds (degrees, minute seconds) to cause failure.

if it was th case would it not leak all over the place? have they? these are the things i would like to know.

I am going to ask around a few otehr forums, i know the kitcar guys have an updated getrag differential so I will see what they can tell me.
As to leaks, it would depend where the crack appears. If it's higher than the differential fluid it may not leak.

Good idea to visit the V Forum as these guys really abuse the equipment. I read the V has a two piece drive shaft and the differential is different. I think Ody may have said that. The 469HP STS would surely have an upgraded differential..if not I see mucho problems.

As you know CMS has been testing and have blown over a half dozen gear boxes.
 

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Discussion Starter #10
so uh robert...
ever get an answer on the whole sema thing?
 

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Kael said:
yes robert, i read that post by cms ltd.

what i am wondering is if this is such a problem why dont we see more of it.
is the diff in the cts the same as the cts-V?

i have seen diff's fail from simple stupid things like a sloppy install, it only has to be off kilter by a couple of seconds (degrees, minute seconds) to cause failure.

if it was th case would it not leak all over the place? have they? these are the things i would like to know.

I am going to ask around a few otehr forums, i know the kitcar guys have an updated getrag differential so I will see what they can tell me.
People say they have problems, but we don't know who and how big a problem it really is??
 

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RobertCTS said:
It would take some time using the search feature but I recall numerous threads regarding differential failures both in the CTS forum and the CTS-V forum.

Here's 13 pages from the V Forum.
http://www.cadillacforums.com/forums/showthread.php?t=16314&highlight=Rear+end+failure
The problem with this train of thought is that there are many Cadillac owners who are not even members of this forum. What is posted on this forum may only be a small fraction or it could be a large group. It's impossible to tell for sure just how bad it is based on just this forums postings.
 

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CTS4me said:
The problem with this train of thought is that there are many Cadillac owners who are not even members of this forum. What is posted on this forum may only be a small fraction or it could be a large group. It's impossible to tell for sure just how bad it is based on just this forums postings.
I agree with your thinking to some degree. The Forum doesn't necessarily represent the the cross section of CTS owners. But I think they are autophiles who are more conected to their cars. When a consistent problem surfaces it should send up a red flag. At least it gets my attention.
 

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The cracks in the sand cast aluminum carrier case have appeared in a variety of places. The majority of them (95%) appear above the gear fluid reservoir so fluid leak is not going to be your first indicator. I just acquired an 8 megapixel SLR camera and as soon as I figure out it's workings, I will post a variety of pictures showing exactly where the cracks appear in the aluminum casing. The majority of them seem to appear at the end of the rear drive shaft yoke. As a temporary fix, we have installed a solid billet machined spacer bracket that is similiar to the pinion bushing manufactured by BMR.

The difference with our pinion pushing is that ours is 360 degrees in diameter, 3/8'th thick solid forged billet and chamfered to meet the carrier face with grade 8 hardware.

And it by the way is a HUGE HUGE HUGE problem on the CTSV and will rear it's ugly head on the CTS 3.6 the further you push the rear wheel torque beyond the OEM standard.

By contrast, the BMR pinion support on the rear driveshaft is shaped like a "horse shoe" and does not provide 360 degree pinion support protection.

Is this the permanent fix? More than likely not as it too is a band-aid on a defective and under engineered carrier case that "should" have been constructed of nodular iron much like a Ford rear, I am sorry to say.

The difference with the Vette carrier is that the tranny bolts directly to the rear carrier without the risk of drive train deflection; which by theory leads us to believe that our measurements of drivetrain deflection under torque or heavy RPM launch is overloading the rear carrier and cracking the aluminum housing on the rear carrier.

Trust me with regard to one thing if nothing else....we don't sell broken or untested items. This rear carrier case is under engineered and the rear wheel torque deflection is causing a shift of anywhere from 1 to 4 degrees and 4 degrees will absolutely grenade that rear!
 

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pietroraimondi said:
And it by the way is a HUGE HUGE HUGE problem on the CTSV and will rear it's ugly head on the CTS 3.6 the further you push the rear wheel torque beyond the OEM standard.
Do you have any actual data to back this statement up?
 

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jteolis said:
Do you have any actual data to back this statement up?
You have to be kidding! You need to visit the V Forum and even our own forum has been filled with problems with the rear differentials. Pete has busted six differential cases of his of his own and has offered to provide us with pics of the casing cracks.
 

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RobertCTS said:
You have to be kidding! You need to visit the V Forum and even our own forum has been filled with problems with the rear differentials. Pete has busted six differential cases of his of his own and has offered to provide us with pics of the casing cracks.
That's what I asking for, so far its all been anecdotal evidence. I'm looking for real data, its a legitimate question, this is a CTS forum where we discuss stuff right? Am I saying something wrong Robert?

How many CTS are out there? How many rear diffs have failed, under what circumstances, etc. Simply saying its a "huge" problem, dosen't make it so, if someone has actual evidence it would be real nice for them to share it with us.

SO Pete killed 6 differentials? What did he do to cause that to happen? HOW IS HIS CAR DIFFERENT FROM OURS?
 

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jteolis said:
That's what I asking for, so far its all been anecdotal evidence. I'm looking for real data, its a legitimate question, this is a CTS forum where we discuss stuff right? Am I saying something wrong Robert?
I think the data is the countless complaints by many forum members having to replace their differential..some have replaced it more than once. Pete's offering pictures. What do you want..a scanned service receipt from a member who had theirs replaced? You get a member or two with a complaint, maybe its B.S. but when you get as many that are posted in our Forum and the V Forum you got to realize there must be a problem here. It was enough to concern me. Thankfully I have an automatic saving my differential the abuse received a manual.

Did you say anything wrong? I think it's your demeanor. One can read into your question that these posters are liars and you need concrete evidence in your face before you will believe them. Intended or not I can see it as will others.
 

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RobertCTS said:
I think the data is the countless complaints by many forum members having to replace their differential..some have replaced it more than once. Pete's offering pictures. What do you want..a scanned service receipt from a member who had theirs replaced? You get a member or two with a complaint, maybe its B.S. but when you get as many that are posted in our Forum and the V Forum you got to realize there must be a problem here. It was enough to concern me. Thankfully I have an automatic saving my differential the abuse received a manual.

Did you say anything wrong? I think it's your demeanor. One can read into your question that these posters are liars and you need concrete evidence in your face before you will believe them. Intended or not I can see it as will others.
OK, concrete evidence, and what is wrong with that? :banghead:
 
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