: Couple "Diff" Questions.



SevillianSTS
10-23-11, 11:52 PM
2007 V
So I complained to the dealer about the diff whine, doesn't seem like he is very interested in looking at it unless its broke. He metioned a high performance Vette diff fluid he could change out.
I'm at 74k. bought it with 67k (highway miles)
I swear I heard / felt a clunk when I turned out of my parking spot at work today; either rear end, or e-brake stuck a little.
Still drives fine. Drove in circles and romped on it a few times.

-Do they show signs / symptoms before they go?
-Is there a way to tell which revision Diff it is ?
-Should I just blow it out and be done with it ? if so, any suggestions how to do it more "quickly" rather than shaking the car apart on wet pavement. Wet pavement is violent... even when not romping on it, it jumps like crazy, windshield washers came on one time from the hop.

I don't really enjoy "destroying" my car, but I have warranty through GM still, plus an extended warranty (3rd party).

- If they replace it, do they reuse all the old bushings and such?
I was under there checking it out... is it normal for the driveshaft to move in and out of the diff fairly easily. I'm assuming yes, but just checking.

One last one... I noticed I leaked a puddle of coolant, I did just romp on the gas shortly before pulling in and parking... but the cap was tight, and the level was still where it should be...

Any suggestions / advise.... ?
Thanks

CadzillaTN
10-24-11, 01:45 AM
If it's whining I'd just dealer hop until someone replaces it... Keep the back seats down and radio off, and take the service mgr for a dive. It's certainly possible to snap it on purpose but why stress everything else in the drivetrain trying...if you must, a few 5k clutch dumps should get the job done.

New diffs come with a new bushing.

Coolant could be the radiator lower hose leaking, or it could be leaking at a seam on the top. Usually shows itself after high rpm fun. Could also be a leaky water pump. I'd bring up both at the next dealer visit. Tell them it stinks like coolant every time you drive. Kind of tough to get this replaced because often the coolant is not visibly leaking.

lollygagger8
10-24-11, 10:48 AM
:yeah:

Houdini
10-24-11, 10:50 AM
+1 to what CadzillaTN said on finding a better dealer. Mine was replaced twice for whine. The last replacement (a gen 4 diff) ended up being strong and quiet even after 18k miles when I sold it. Keep in mind that some people get brand new gen 4s that whine out of the box. That would suck. Unless yours is howling like crazy and you can't ignore it, I wouldn't worry about it. I certainly wouldn't try breaking it on purpose.

You'd probably break an axle or cv anyway before you break your gen 3 diff. I don't recall seeing anyone break a gen 3 (06/07).

rand49er
10-24-11, 11:03 AM
... I don't recall seeing anyone break a gen 3 (06/07).But they do start talking back to you.

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

CancerJCC
10-24-11, 11:22 AM
2007 V
So I complained to the dealer about the diff whine, doesn't seem like he is very interested in looking at it unless its broke. He metioned a high performance Vette diff fluid he could change out.
I'm at 74k. bought it with 67k (highway miles)
I swear I heard / felt a clunk when I turned out of my parking spot at work today; either rear end, or e-brake stuck a little.
Still drives fine. Drove in circles and romped on it a few times.

-Do they show signs / symptoms before they go?
-Is there a way to tell which revision Diff it is ?
-Should I just blow it out and be done with it ? if so, any suggestions how to do it more "quickly" rather than shaking the car apart on wet pavement. Wet pavement is violent... even when not romping on it, it jumps like crazy, windshield washers came on one time from the hop.

I don't really enjoy "destroying" my car, but I have warranty through GM still, plus an extended warranty (3rd party).

- If they replace it, do they reuse all the old bushings and such?
I was under there checking it out... is it normal for the driveshaft to move in and out of the diff fairly easily. I'm assuming yes, but just checking.

One last one... I noticed I leaked a puddle of coolant, I did just romp on the gas shortly before pulling in and parking... but the cap was tight, and the level was still where it should be...

Any suggestions / advise.... ?
Thanks

-Is there a way to tell which revision Diff it is ?
On top of the diff you will find the part number. While installed though you will need to snap pictures with a camera. (Its on the top and you can't see it)

is it normal for the driveshaft to move in and out of the diff fairly easily?
No. There is no way the driveshaft was moving in and out of the diff. You may mean it was moving forward and aft but definitely not in and out of the diff.

I noticed I leaked a puddle of coolant...
Radiators are a common issue with V's. Tell your dealer.

CadzillaTN
10-24-11, 12:19 PM
+1 to what CadzillaTN said on finding a better dealer. Mine was replaced twice for whine. The last replacement (a gen 4 diff) ended up being strong and quiet even after 18k miles when I sold it. Keep in mind that some people get brand new gen 4s that whine out of the box. That would suck. Unless yours is howling like crazy and you can't ignore it, I wouldn't worry about it. I certainly wouldn't try breaking it on purpose.

You'd probably break an axle or cv anyway before you break your gen 3 diff. I don't recall seeing anyone break a gen 3 (06/07).

I agree with this as well. The grass isn't always greener.. I got 3 new gen4 rears alone, 2 howled out of the box. I was bummed. I tried for a 3rd just before my warranty expired and got it. It has the 'standard' light whine, very similar to the gen3 that came out before my 1st gen4. If it stays that way and doesn't get any louder, I'll be content (although I'll always be frustrated that I couldn't get a quiet one with 3 tries).. My plan is to just sound deaden as much of it as I can and move on. It's much easier to deal with now that i'm "stuck" with it. When under warranty, I just couldn't justify ignoring it...

SevillianSTS
10-24-11, 04:34 PM
-is it normal for the driveshaft to move in and out of the diff fairly easily?
No. There is no way the driveshaft was moving in and out of the diff. You may mean it was moving forward and aft but definitely not in and out of the diff.

I noticed I leaked a puddle of coolant...
Radiators are a common issue with V's. Tell your dealer.

Yes, i meant forward and back, just a little 1/4" , I am assuming it accounts for when the suspension moves. There is a little rubber boot that was over the end of the shaft where it connects to the diff... that is where the movement was.


The coolant leak is right under the resivor. Just in front of the drivers door, it was dripping from the car when I got out. Yes it was after I just had a little fun....
Do I need a new cap or something ?

CancerJCC
10-24-11, 10:44 PM
Yes, i meant forward and back, just a little 1/4" , I am assuming it accounts for when the suspension moves. There is a little rubber boot that was over the end of the shaft where it connects to the diff... that is where the movement was.


The coolant leak is right under the resivor. Just in front of the drivers door, it was dripping from the car when I got out. Yes it was after I just had a little fun....
Do I need a new cap or something ?

Yeah that is normal. Just the CV.

And you may need a new cap. Others have reported them leaking as well.

Aurora40
10-25-11, 09:46 AM
FYI, my diff (Gen III presumably) has a very light whine you can hear if you are driving with the radio off, windows closed, stock exhaust, and reasonably quiet tires. You can tell it's (probably) the diff (vs road noise) because at steady speed the sound will go away if you let off the gas. I also get a bit of noise when turning slowly, like in a parking lot. I've tried to add a bit more limited slip additive, but it didn't help (though it's hard to tell how much went in the diff since you can't fit the bottle up there.)

I don't think it's a sign that the diff is failing. I've changed my diff fluid and it was very clean looking, zero signs of metal flakes. As to the high performance "Corvette" fluid, I think I'd use the stuff spec'd for the V. Not sure if they are the same part # or not, but the V stuff is synthetic and probably as good as what was used in the 'vette.

I sure as hell wouldn't beat on it to try to break it. For one, you might break or weaken something else. For two, it might not break at all, then you'll just have a diff with some whine that you've abused the crap out of. I'd try another dealer, as others have said. And definitely put the rear seatback down so they notice the noise more.

FYI on the coolant, the reservoir bottle is right by where you describe. If it is overfilled (past the "full" line), when hot it can fill completely. It will bleed excess coolant out right into the engine bay/onto the ground. There is no unpressurized overflow like on older cars. So make sure it's not full past the markings before you bother digging in too deep.

SevillianSTS
10-25-11, 12:16 PM
I asked the dealer about the additives for the diff too... he said NO, what do you guys say ?
Thanks

CancerJCC
10-25-11, 06:31 PM
I asked the dealer about the additives for the diff too... he said NO, what do you guys say ?
Thanks

You HAVE to use the additive. I'm sure darkman will be in with the proper .pdf in about 3....2....

Its been discussed before and for whatever reason some dealers aren't on the correct page. Bottom line use it.

mstrjon32
10-25-11, 06:59 PM
Many synthetic fluids, Amsoil included, do not require you to use more additive. I'm running the Amsoil Severe Gear in mine with no additive and have no issues.

Aurora40
10-25-11, 08:09 PM
The FSM says to use the additive, I've no idea why a dealer would say otherwise. I think I would stop taking advice from them.

SevillianSTS
10-25-11, 10:13 PM
Well the dealer has my car right now. Be nice if he says: yea we're gonna change your diff. But if he just says they changed the fluid... I should then get some additive ???
Can I ask the differences in the 3 different Amsoil products 90, 110, and 140 I see a lot of you guys going with any of the three. I'm a "spirited" daily driver; and parked over the winter.
Just read in the manual that the 75w90 is the factory fill.... are there any negative affects to going with the heavier oil? Cause if they change the oil and I see no difference I'm going to change it again with your recommended Amsoil

Thanks Again

CancerJCC
10-26-11, 08:58 PM
Many synthetic fluids, Amsoil included, do not require you to use more additive. I'm running the Amsoil Severe Gear in mine with no additive and have no issues.

Yeah but a dealer isn't putting Amsoil in...


The FSM says to use the additive, I've no idea why a dealer would say otherwise. I think I would stop taking advice from them.

I think there was conflicting info out there (within GM). I seem to remember more than one case of a dealer questioning the additive.


Well the dealer has my car right now. Be nice if he says: yea we're gonna change your diff. But if he just says they changed the fluid... I should then get some additive ???
Can I ask the differences in the 3 different Amsoil products 90, 110, and 140 I see a lot of you guys going with any of the three. I'm a "spirited" daily driver; and parked over the winter.
Just read in the manual that the 75w90 is the factory fill.... are there any negative affects to going with the heavier oil? Cause if they change the oil and I see no difference I'm going to change it again with your recommended Amsoil

Thanks Again

I run 75w90 Amsoil but my diff is quiet as can be. A lot of guys go with a heavier fluid and report marginal decreases in noise but I don't think it helps much. As for adverse effects I don't think I've read of any.

CadzillaTN
10-26-11, 09:42 PM
Well the dealer has my car right now. Be nice if he says: yea we're gonna change your diff. But if he just says they changed the fluid... I should then get some additive ???
Can I ask the differences in the 3 different Amsoil products 90, 110, and 140 I see a lot of you guys going with any of the three. I'm a "spirited" daily driver; and parked over the winter.
Just read in the manual that the 75w90 is the factory fill.... are there any negative affects to going with the heavier oil? Cause if they change the oil and I see no difference I'm going to change it again with your recommended Amsoil

Thanks Again

Let them change the fluid. Then, when it still whines, tell them to change the diff. If they don't, try another dealer. If your goal is a new diff despite the risk of it whining worse, I'd hold off on the amsoil, or at least get it in writing that it's ok for you to put it in. Worst case scenario is them saying you are no longer covered because you didn't use a GM fluid, although I think other fluids meeting spec are approved...still, check on it.

I don't know why some dealers balk at changing diffs out. As long as it's whining, it doesn't cost them a penny to do so.

Could be your service writer. Some if them can be idiots and let their ego make decisions, especially if they feel threatened because you "know" more about your car than they do. I also think they are somehow incentivized to keep costs down.

SevillianSTS
10-26-11, 11:57 PM
Well, I callled them today... he says there is absolutley nothing wrong with my car. I said: but it whines... he said: thats normal, and that there is a service bulletin talking about it. I even left the back seat down before I left.

I also asked them to check the motor mounts cause the car shakes when you shut it off; not terrible, but it does. Is this normal, or is he B.S.ing me again. Cause from what I read on here.. mounts are known to go... and I feel it shake. How do check them myself; just looking at them ?

Also mentioned the front end noise "rattle" whatever you want to call it, makes me think of sway bar bushings.

I just want to get these things addressed while I have warranty to lean on.

Is amsoil a different color than the GM oil? just wondered cause if the same, they'd never know.

I do have another GM dealer that is not too much further away, should I just let them "change the fluid" and then compain again after that.

This dealer has told me before when I had my 99 STS... couldn't figure out why it kept stalling... so I got on here, and you guys helped me figure out that it was bad crank position sensors... $50 and an hour later it was fixed (by me) =)

CadzillaTN
10-27-11, 12:22 AM
He's a jackass. Give that other dealer a shot. Can't hurt anything.. It's all business. Go at the beginning of the month when their budget is fat.

Don't let this dealer do anything, that way you don't owe any deductible. Tell them you're going to get a second opinion..that keeps them from getting ANY revenue.

CancerJCC
10-27-11, 07:55 PM
Well, I callled them today... he says there is absolutley nothing wrong with my car. I said: but it whines... he said: thats normal, and that there is a service bulletin talking about it. I even left the back seat down before I left.

I also asked them to check the motor mounts cause the car shakes when you shut it off; not terrible, but it does. Is this normal, or is he B.S.ing me again. Cause from what I read on here.. mounts are known to go... and I feel it shake. How do check them myself; just looking at them ?

Also mentioned the front end noise "rattle" whatever you want to call it, makes me think of sway bar bushings.

I just want to get these things addressed while I have warranty to lean on.

Is amsoil a different color than the GM oil? just wondered cause if the same, they'd never know.

I do have another GM dealer that is not too much further away, should I just let them "change the fluid" and then compain again after that.

This dealer has told me before when I had my 99 STS... couldn't figure out why it kept stalling... so I got on here, and you guys helped me figure out that it was bad crank position sensors... $50 and an hour later it was fixed (by me) =)

MM's - Its tough to tell because even a visual inspection might not tell much. The fluid INSIDE can be completely gone or sometimes leaking. A lot of the time leaking MM fluid will look like an oil leak though. (On mine one was dry as a popcorn fart and the other leaking but neither looked bad from below).

Diff fluid - The GM stuff is purple and smells differently (I'm 90% sure its those things). Either way its different and don't give the dealer a chance to void your warranty.

Go to another dealer and complain until they replace your diff. Although there are more than one account of generation 4 differentials whining out of the box. (My gen III is quiet as a mouse). Furthermore get your self worked up before heading to the dealer and tell them you refuse to drive "clients" (whether applicable or not) around in a CADILLAC that makes this much noise. Rant and rave, the warranty is there for a reason. I know easier said than done but sometimes you have to be an ass to beat an ass....

SevillianSTS
10-28-11, 04:22 PM
Well I just picked the car up, tried raising a little more hell before leaving. They said they heard a "slight" whine; "but it is normal according to the service bulletin". I said: so I have to drive a cadillac that whines... he says yes. grrrrr.
So I took the service manager for a ride; he said he hears it, asked him what or who sets the threshold for how loud it must be for it to need "worked on".... blah balh blah...it is normal compared to other cars of the like.... I said... lets go get in a used CTS they all have a getrag rear end. He sad NO.. has to be identical car. I said... so it is my responsibility to find another CTS-V for you to verifity this with.
I am gonna take it back monday so there body shop guy can pop a dent out of the back door... he is good, did work on our other car.
Service guy said while it is there... he is gonna take the "Cadillac" head mechanic to ride with him and get his opinion.
Assuming.. he will say the same thing, I am going to take it to the other dealer and try again.

Anybody out there, have a 2006 / 2007 V or know someone who does, up here in teh South Bend, IN Area ?? I'd love to have another one to pull in with and show him. Maybe I should make a new thread to get some attention on that question.

Thanks again

2007ThunderV
10-30-11, 01:38 PM
i had a whine in me rear end.
i took it in , and ii told them i wanted a new diff, and with a bit of arguing they put one in, along with a new drive shaft(dont ask me why)
i am from canada but it shouldnt matter. i told them i drive clients around and its unacceptable, plus i have exhaust on the car, and i could here the wine over the exhaust.
i had mine replaced with 25000km on the odometer.
just keep dealer hoping until some one does it.
also its just a matter of them agreeing to do it, let them order it, and reschedule an appt, it took them 5 hours to do my swap, had my car back same day.

2007ThunderV
10-30-11, 01:39 PM
also another note, i have 1400km on the new diff , and a slight wine is comming back when coasting to a stop from 60km and below(car in nutral)
not loud enough for me to car at this point.

DDS rollin a CTS
10-30-11, 03:28 PM
Anybody out there, have a 2006 / 2007 V or know someone who does, up here in teh South Bend, IN Area ?? I'd love to have another one to pull in with and show him. Maybe I should make a new thread to get some attention on that question.

Thanks again

I'm in Lafayette. Dont know if I'd be much help though because my diff whines too and my dealership is also denying the claim. Might have to go try my old dealership down in Indy...

SevillianSTS
11-01-11, 12:51 AM
Well.... The dealer called back, said his dent repair guy got the dent out and he can't tell where it was.
Plus... he took the head Cadillac Mechanic for a ride... and mechanic told him that the whine was more than normal... so they're gonna fix it.
Wooo Hooo
Thanks for all the input guys.

Houdini
11-01-11, 08:28 AM
Awesome news. Hopefully the new one is whine free.

SevillianSTS
11-01-11, 10:48 AM
Do they put gen 4's in all replacements now... or are there still some gen 3's out there ?

Anyone know what part numbers to look for when figuring which one you have ?

Break in is: drive like grandma, and no constant speed for 500 miles right ?

Should I change the diff oil after "??" miles due to break in ? GM Oil, or Amsoil ?

Houdini
11-01-11, 01:52 PM
They should only put the latest part number in there which is what I call gen 4 (because there have been 4 part numbers). Some people call them gen 3 since the first part number wasn't used very long at all. Either way the latest part number came out in late 2008. This thread has part # info as well as info on break-in procedure from darkman:

http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-general/204475-new-gen-4-diff-oil-also.html

Cadillac Cust Svc
11-01-11, 02:09 PM
SevillianSTS,
It is awesome that they got the dent out and that they are going to take care of the whine! Let us know how it is when you get it back!
Breanne
Cadillac Customer Service

C66 Racing
11-06-11, 10:14 AM
Should I change the diff oil after "??" miles due to break in ? GM Oil, or Amsoil ?

I suggest changing it out fairly soon after break-in as most diff wear occurs at break-in and if you leave those wear products in your diff it may accelerate wear. I sampled (and changed) my factory fill fluid at 10k miles. Blackstone Labs comments on my sample:
"We normally expect to see high wear in factory fill differential sample, though these levels are a little excessive, even for that."
2006 Cadillac CTS-V Used Oil Analysis Factory Fill Differential Fluid (http://www.c66racing-synthetics.com/TestResults/CTS-V%20Differential%20UOA.htm)

Changed to the AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (http://www.c66racing-synthetics.com/Product%20Bulletins/SVGPB.htm) (Product Code SVGQT) at that point and used that until I sold the car in 09 when I moved to DC.

FYI, responding to a couple comments above:
- The AMSOIL Severe Gear doesn't need additive, but that is because it comes with additive already in it. I use this fluid in my 02 Corvette Z06 which I race, and used it in my 06 CTS-V without extra additive and neither diff chattered. Diff chatter is different from diff whine. The chatter occurs when the diff clutch plates turn at different rates, like when turning sharply backing out of a driveway or parking spot. If the fluids friction properties are correct, the diff plates will slide or slip. Incorrect and they will slip and catch, or chatter. FYI, GM's newer diffs on the current gen V and Corvette require more additive than the last generation due to a change in the behavior of the clutch plates. For current gen V and Corvette diff I recommend adding one bottle of AMSOIL Slip-Lock Differential Additive (http://www.c66racing-synthetics.com/Product%20Bulletins/ADAPB.htm) (Product Code ADATB).
- Going to a higher viscosity diff fluid (110 or 140) may help diff whine, but at the penalty of extra fluid pumping losses, lower net HP and mpg. A 110 has a viscosity about 20% higher than that of a 90 and your diff will be pumping that fluid all the time. I've never tried a higher viscosity, and in my Vette I definitely wouldn't want the extra fluid friction, so I can't comment on whether it helps diff whine or not, but worth considering the penalty you pay in lower performance to minimize the whine.
:cheers:

SevillianSTS
11-12-11, 12:46 PM
82607 and the answer is..... "Nice and quiet"

Houdini
11-13-11, 12:06 AM
Awesome! :thumbsup:

SevillianSTS
11-13-11, 12:18 PM
I'm driving her so easy right now i'm at like 19.1 mpg any other time i get like 14 - 15 never knew I could get that mileage out of her... lol.

Can't wait to unleash the fury after break-in.