I've recently been doing some spirited driving and the tranny temp read 210F, which gives me warning to reduce speed. Is this a frequent occurrence to anyone else during said driving? Is this related to a diff overheat too?

I would interested in knowing this also. Is this warning related to tranny or is the diff fluid over heated or low which cause this over temp condition. I want to do some seriouse big track (daytona) speeds and don't want to burn up a diff doing so. Sure would like one of our SEA certified caddy Mech's to chime in here and set us straight before it cost us seriouse cash.

Mike :thumbsup:

I'm hitting about 140mph (easily) during my spirited driving sessions which last about 20mins. I wouldnt think this should be an issue. Not for how this car is advertised.

Have you checked the fluid levels? There are posts regarding low levels/heat issues. Search
Regards,
GG

Yes I did. I read similar posts and immediately had dealer inspect fluid levels. All checked nominal. Last session tranny temp read 223F before warning message this last time.

Hello,
That trans temp doesn't seem excessively hot. Did you get a warning light for the differential fluid overheating or was it directly related to the trans? We have installed custom trans and diff coolers to alleviate this from happening.

http://i143.photobucket.com/albums/r134/ctd3rnd/Converted_MG_6525.jpg

Please note that these are pre-production images. Here we have installed (2) coolers and (1) reservoir. The first cooler (behind the smaller cooler) is for the supercharger system. The second smaller cooler is being used as a trans cooler. We have noticed temps up to 190 under very strenuous driving conditions only to see it rapidly cool back off to normal temps.

http://i143.photobucket.com/albums/r134/ctd3rnd/Converted_IMG_4254.jpg
Here is a pre-production image of the rear diff cooler with 1550CFM fan and integrated thermal switch. This keeps the diff fluid nice and cool...

Let us know if you know what dictated the reduce speed notification.

Thank you,


Dr. Design
D3 Cadillac

Here is a pre-production image of the rear diff cooler with 1550CFM fan and integrated thermal switch. This keeps the diff fluid nice and cool...


Color me interested (assuming my CTS-V doesn't get sold). Any early guesses as to a price for this bad boy when you're done with it?

jas (diff overheatin'R'us)

So, here's an update: I ran 4 sessions on Friday. Each session I started with the Tranny Temp reading about 140F. About 7 laps into my session, (2.9mile course) my tranny would hit around 220F-230F and I would get a 'Differential Overheating Please reduce speed' message. So, I got about half the drive time I could have because I always had to come in early because I had a diff overheat warning. I was on stock street tires too, so I wasn't loading up the diff real hard with RComps.

I tracked my M3 all the time, all day long and not one time, ONCE, did I ever have to cut short any track time because of a mech issue. Disappointing at best.

Other than that, the car was awesome on the track. Got complements from everyone how well it did out there, when it was 'cool' enough to be out there. Brakes, umm...ya. They are awesome. OMG, I love the brakes.

I'd be curious what the cars at Mont (CTS-V Challenge) and the 'Ring' car had in terms of mods to the diff. Because by my estimations, those cars wouldn't last long.

I tracked my 2004 V more than 50 times. I always used top of the line fluids (for me, Redline) and this meant transmission fluid, brake fluid, power steering fluid, oil, etc. That, along with good brake pads (Hawks) and good tires (Hoosier R6 or Toyo R888) was the best bet I wouldn't have problems.

Sure, I'm all about changing things out (components, consumables, etc) to be more robust on the track. I'm really commenting on that I feel the stock setup was a little weak. I mean seriously, 6-7 laps on a 2.9 mile course and the car starts complaining? Ya, again, disappointing. Am I going to remedy this by 'upgrading'? Yes. However, that's not how this car is advertised or sold. It is advertised as a very robust and complete platform. Just imagine during the CTS-V challenge if it was a 10 lap average or something and the CTS-Vs all pulled out because they kept overheating. Listen, I'm not saying that other brands wouldn't have similar issues. I'm just saying I tracked my M3 before and never had a single instance of an issue and on my first track day with the CTS-V, I get to run half the time because of "Diff Overheating, reduce speed."

I did upgrade brake fluid before the track day, because I was certain I would boil my stock DOT3.

I'm just saying I tracked my M3 before and never had a single instance of an issue and on my first track day with the CTS-V, I get to run half the time because of "Diff Overheating, reduce speed."

A couple of things:

1. The stock differential isn't weak. In fact, it's near bullet-proof. The problem is that it generates a LOT of heat under stress because of its heavy duty nature. Given the heat, the concern here is that the diff. fluid could break down if stressed too much (similar to boiling brake fluid). Thus the temperature sensor and warning chime.

2. GM fully intended to release a differential cooler for those folks that wanted to track their Vs. Unfortunately, that cooler never materialized in the US given GM's other financial woes. I'm sure you can agree that a differential cooler for a VERY small volume car is a low priority compared to other things...

jas

So, I'm thinking that the first thing I should do is try a different fluid in the differential. However, I'll still see an over heat warning since the car won't know I have a better fluid. Actually, will a different fluid have better heat rejection properties and keep the diff cooler?

So, I'm thinking that the first thing I should do is try a different fluid in the differential. However, I'll still see an over heat warning since the car won't know I have a better fluid. Actually, will a different fluid have better heat rejection properties and keep the diff cooler?

You're going to get multiple different opinions on this one. Here's mine (based on a very long conversation with my HPVO buddy) ... don't bother. Stick with the stock fluid, just make sure it's filled properly with the apropos limited slip additive. You'll still get the overheat warning with other fluids, and you may not get the same level of overall protection with them (a certain "A" fluid comes to mind).

The car needs a diff cooler. There are no ifs, ands, or buts about it. All of the heavy track testing GM did was with the diff cooler (and track brake rotors) attached. All of the cars that the press beat on during the introduction also had the diff cooler.

jas

The car needs a diff cooler. There are no ifs, ands, or buts about it. All of the heavy track testing GM did was with the diff cooler (and track brake rotors) attached. All of the cars that the press beat on during the introduction also had the diff cooler.

jas

Really? Huh, didn't know that. Yep, gonna buy a diff cooler. Is this an issue with dealers get one? Do they care?

I threw the question out there on the internal forum to get an answer one way or another if the Rng V or the CTS-V Challenge V's had the diff coller or not. We will see what the response is. On Gen I V's I think the Diff was one of the main problems on the car, axle hop used to trash it pretty hard. This one is so much better and robust. So for you mechanical guys out there, what heats the fluid? Is it just speed, or is it acceleration. My question is can the V sustain a high speed like on the autobahn or is it just tracking it where you have the foot to the floor over and over.

Great to hear that when you were out there Nic the car was a beast. Did you get a ride in your car with one of the instructors, it would have been cool to have someone push it a little beyond what you felt comfortable doing in your own personal car.

Really? Huh, didn't know that. Yep, gonna buy a diff cooler. Is this an issue with dealers get one? Do they care?

What do you mean "issue with dealers get one?" Are you talking about modifications and whether a dealer would cover it? Or something else? If the former, then I'd imagine dealers would cover the diff cooler, assuming it was the GM SPO one. However, that diff cooler doesn't exist (for us mortals) for purchase. So you're forced to go aftermarket.

Close examination of certain foreign Vs will show a differential cooler. I'm not sure, but I think GM had to include it on those cars. I don't know the specifics there. However, that cooler isn't available to us here in the states. Yet.

jas

So for you mechanical guys out there, what heats the fluid? Is it just speed, or is it acceleration. My question is can the V sustain a high speed like on the autobahn or is it just tracking it where you have the foot to the floor over and over.

It's torque going through the diff that does it. Whether it's changing torque or just a constant one. At a reasonably high RPMs, there's enough torque going through the diff that it gets a little toasty. I don't think it matters whether the RPMs are due to constant changes in speed or a constant high speed.

jas

Two items that I have always considered as part of this issue.

1. The V1's may very well have had the same heating issue, but because of the lack of a diff temp sensor, non of us that tracked it knew about the issue.

2. The V2's vver temperature warning may be set too low. I'm not sure what the breakdown temp of the rear fluids are, but 220F-230F sounds low to me, perhaps someone with a bit more knowledge of the properties of rear end fluids may chime in here ?

Jason, what's your issue with a certain oil (starts with "A") ?

Jason, what's your issue with a certain oil (starts with "A") ?

It was suggested to me that we be a bit careful of the types of oils we put in our differential, is all. Read between the lines. :-)

jas

I know the ring V had one installed. Saw that in person at Fontana. The challenge V... don't know. Its actually pretty noticeable (see image). From the product drawings I saw this would have been the production unit....
http://i143.photobucket.com/albums/r134/ctd3rnd/_MG_3453.jpg

I don't recall what button activated the fan & pump, but there were many difference buttons and switches that were not factory.....
http://i143.photobucket.com/albums/r134/ctd3rnd/_MG_3449.jpg


We will have pricing and availability up shortly. We can build one-offs now.

Thank you,

Dr. Design
D3 Cadillac


I threw the question out there on the internal forum to get an answer one way or another if the Rng V or the CTS-V Challenge V's had the diff coller or not. We will see what the response is. On Gen I V's I think the Diff was one of the main problems on the car, axle hop used to trash it pretty hard. This one is so much better and robust. So for you mechanical guys out there, what heats the fluid? Is it just speed, or is it acceleration. My question is can the V sustain a high speed like on the autobahn or is it just tracking it where you have the foot to the floor over and over.

Great to hear that when you were out there Nic the car was a beast. Did you get a ride in your car with one of the instructors, it would have been cool to have someone push it a little beyond what you felt comfortable doing in your own personal car.

What do you mean "issue with dealers get one?" Are you talking about modifications and whether a dealer would cover it? Or something else? If the former, then I'd imagine dealers would cover the diff cooler, assuming it was the GM SPO one. However, that diff cooler doesn't exist (for us mortals) for purchase. So you're forced to go aftermarket.

Close examination of certain foreign Vs will show a differential cooler. I'm not sure, but I think GM had to include it on those cars. I don't know the specifics there. However, that cooler isn't available to us here in the states. Yet.

jas

Ya, sorry about that. What I meant is - if a dealer sees you've installed an aftermarket diff cooler, and they gonna have a problem with it? i.e. am I voiding ANYTHING with my warranty?

I threw the question out there on the internal forum to get an answer one way or another if the Rng V or the CTS-V Challenge V's had the diff coller or not. We will see what the response is. On Gen I V's I think the Diff was one of the main problems on the car, axle hop used to trash it pretty hard. This one is so much better and robust. So for you mechanical guys out there, what heats the fluid? Is it just speed, or is it acceleration. My question is can the V sustain a high speed like on the autobahn or is it just tracking it where you have the foot to the floor over and over.

Great to hear that when you were out there Nic the car was a beast. Did you get a ride in your car with one of the instructors, it would have been cool to have someone push it a little beyond what you felt comfortable doing in your own personal car.

Loved the car on the track. It was great. I ran 7 seconds faster per lap than I did in my M3. Very, very nice.

Ya, sorry about that. What I meant is - if a dealer sees you've installed an aftermarket diff cooler, and they gonna have a problem with it? i.e. am I voiding ANYTHING with my warranty?

The dealer can't void your warranty. It's against the law for them to do that. They can refuse to cover specific work based on modifications, but they can't void the warranty on the entire car. If the diff cooler contributed to whatever reason your car is getting repaired, then, yes, the dealer can refuse to cover that work. But they can't say, "Hey, you have a diff cooler installed, we're voiding the car's entire warranty."

jas

Must be the automatic?

Norm

Must be the automatic?

Norm

oh ya....was there any doubt? If I wasn't plagued by an ankle disease in my clutch foot which causes me insane pain, I'd have a manual.