NOSLO6

Hi folks,

I ran two HPDEs at NJMP (wonderful track, great time) this spring and though temps were only in the high 50s I can see that I'll need to add a more substantial oil cooler.

• My question -- should I also be budgeting to add a diff cooler and trans cooler at this point? Both or just one? Who has run into an overheating diff or trans and under what circumstances?

As background, my C6 is an M6, w/ Z51 makes approx 480hp at the wheels, has 3.90s, and I drive it as hard as my skill level allows. I'm running R888s and carbotech X10/X8 pads. I'll be running only 4-5 HPDE days a year for the near future.

Thanks all-- surprisingly little on when exactly heat in the trans and rear becomes an issue with C6s out there.

Rob Willis

Good questions that I'll be following as well.

Stock Z51 C6s have tranny coolers from the factory, as far as I know. My build sheet lists one. I think its in the radiator with the factory oil cooler. They also have external power steering coolers.

I'm planning on upgrading to a DeWitts radiator with built in tranny cooler and going with an external oil cooler (either Z06 takeoff or larger) and maybe an Accusump.

Not sure how hard you'd have to run to really need a diff cooler?!

Ms Eliz

Great questions!
I have an 03 Z06 384 RWHP and I got a trans overheat message during a HPDE on Monday. I'm curious if I should change from the OE Trans fluid/add cooler or what so I'll be watching this thread too!

Ms Eliz

longdaddy

I now get overtemp warning on any track where I use 2nd gear for more than a few seconds.

The warning comes on at ~270 degrees at which point you are able to see the trans fluid temperature on the HUD (C5Z). If I keep hammering on the car the temp comes up a little more but always seems to stabilize around 280. I told myself that if I see temps go over 280 consistently I will get a cooler. I am probably a dumbass for not doing this already and there is a chance I will have to buy a new transmission at some point because of it.

I have no idea what my diff temperatures are but likely higher than they should be, both diff and trans fluid had burned smell last time I changed them.

I run full synthetic fluids in both transmission and diff.

0Randy@DRM

Here is the main reasons why you get the dreaded over temp light. First the exhaust is close to the transmission, a simple header wrap around the transmission will reduce temps.

2nd The rearend has a limited slip diff and that causes a ton of heat. The worst part about it, it's connected to the transmission. Both parts being alumium that extra heat transfers up to the transmission.

3rd The LS power plant does it's job at making power

We offer transmission and diff coolers for both C5 and C6. They do require some talent in the shop to install.

Let me know if you have any questions!
Randy

KBlanke

The added coolers will make a huge difference

longdaddy

by the way, i did the wrap, it did not seem to make a significant difference

NOSLO6

Thanks for all of the feedback. Randy, I spoke with one of your staff mechanics Friday afternoon and he offered some great feedback as well.

Any C6 MN6 road racers with actual experiences of high manual trans temps or overheatted diffs?

Another member with a not dissimilar car AND a diff temp gauge reported temps getting up toward 300F here. It all adds up to considerable $ and time investment for cooling since I'll be adding a larger external oil cooler as well, but I'm beginning to think it's a worthwhile investment.

Jason

You're wrapping the transmission or the exhaust pipes?

NemesisC5

My car is 02 C5Z with R888's & 394whp (346 cid); Last fall I got the transmission 279* on the DIC then looked again two laps later and it read "transmission hot". I installed diff cooler and no more issues. I plan on doing the transmission cooler as well when I do some tranny upgrades. I have Dewitts rad but use external oil cooler, since install I have not seen oil temps above 235* or ECT above 210*. My personal $.02, I prefer not to add heat to the rad with oil or tranny coolers.

Too Tall Bob

When I first started tracking my C5 Z06 a few years ago, I would get trans high-temp warnings, but I ignored them. Soon after, I lost the trans.

When I installed the new trans, I also installed a DRM trans and diff cooler. No more high temp warnings and no more trans replacements.

As Randy said, it might take some talent and patience to get it installed correctly, but I love to hear the buzz of those pump motors every time I take it onto the track!

NOSLO6

Aside from install time which isn't a worry (years of wrenching on the Buick have made me very patient), any negative trade-offs to running these coolers?

I imagine it's easy enough to block them off in cold weather or run a switch to activate the pumps (if they're electric, that is). Do the pumps live for a reasonably long time?

Thanks for all of the great feedback folks.

AU N EGL

I put trans and oil coolers ( with accu-sump) after my third DE. Best mod I ever did for my car.

Electric switch on each

Too Tall Bob

If you have any mechanical or fabricating ability at all, they're easy to install. You may need to do a little fiddling to get the brackets to fit perfectly, but considering the amount of room (or lack of) that you have to fit the coolers into inside the wheel wells, it's a good unit by DRM. The pumps are good quality and should last indefinitely.

The most important part is making sure that you route the oil lines away from anything that might rub on them and cause a leak.

I have them on a separate switch so they are only on when I want them on. I don't use them when I'm driving on the street. The other added benefit of having coolers is that it adds to the overall fluid capacity of the trans and diff.

wmk32

I'm pretty sure the Z51 already has those coolers so if anything you might just want to add bigger ones if you think it is an issue.

I have a base model C6 and have not found any real need to add a cooler for the trans or diff. I did add a Z06 oil cooler which made some difference although not as significant as i was hoping.

0Randy@DRM

Sorry about that Wrapping the pipes near the transmission. I haven't been getting much sleep lately, 14-16 hours a day at the shop will do that to a guy
Randy

Jason

Ok, that makes more sense. Think I'll do that today while I have the car up on stands. When my wife and I both drive we've been getting high trans temps this year.

NOSLO6

Thanks for all of the feedback folks. Any other thoughts do chime in.

ssdeuce

Does anybody have any installation pics to share? What is involved to get the fittings on the trans and rearend? Do you have to drill and tap a place for each line or is there already a place for the lines? I haven't gotten the warning yet but it sounds like a good offseason project to save up for.

2002rich

C5 Z06 with DRM Trans and Diff coolers. No issues whats so ever whereas my previous C5 would trigger the "tranny hot".