thisismyusername

Hi folks,

It's been a while since I've been on here. I had to trade in my Z06 and get a Grand Sport (damn, I loved that Z). The Grand Sport has an automatic transmission. I plan on getting back into road racing this coming season and was wondering what I should do with regards to the automatic transmission? What is a good performance fluid for the automatic transmission? I've heard about automatic transmission fluid coolers; who makes a quality one? I won't be driving the Grand Sport near as hard as I did the Z06, but want to make sure I don't have any issues with the automatic transmission.

Thanks!

Solofast

The easiest thing to do is rip out the auto and put in a stick...

Ok, maybe I'm being a bit facetious, but only a bit...

There is a thread in the autocross and road racing forum where a guy detailed what he did to keep a C5 automatic alive and it was a huge amount of work...

Automatics generate a lot of heat and heat kills them. When you are at wide open throttle the lockup clutch is disengaged and the torque converter is making heat all the time. No big deal for a drag racer since he only runs it for 12 seconds at a time but even a few laps on a road course in anger will have most automatics cooking in their own juices.

Remember that clutch plates in an automatic are basically paper impregnated with resin. If they start to slip at all you are hosed. For that reason you need to keep the fluid cool to keep the clutch plates cool and making the fluid better will just allow the clutch plates to fail sooner...

You absolutely need a big cooler, mounted up front and large lines to get the fluid up and back without as much pressure loss. Keeping the fluid cool is really the key.

mikeCsix

What year is your GS? If its 2012+ I think you will like the way the A-6 shifts. I can run mine right up to 6k at WOT it will shift without having to back off the throttle.

I upgraded my radiator to a DeWitts with an EOC/TOC to help the temps. It helps but more cooling is needed for me. I'm a group 'B' driver to give you an idea of how hard I run on the track.

One item that may help is a differential cooler. The A-6's don't have one. There is a T-1 kit listed in the gm parts manuals for the C5-Z that is one of the less expensive ways to upgrade, DRM put together a kit that is similar. Incidentally, the T-1 kit is a transmission cooler so would have to be adapted to the diff, not all that difficult so I'm told. What I like about it is there is a temp sensor to turn the pump on/off, the DRM uses a mechanical switch. Depending on the current and wire length needed to operate the pump, I would look at running the power for the pump motor through a relay.

I'm also looking at installing Setrab oil coolers, one for the transmission and one for the engine oil.

I also do not want to cut the car up to adapt it for track use. This is my dd and fun weekend car that performs outstandingly on the track.

There is another driver out here that ran his C-6 A-6 really hard for several years as he made his way up the hpde ranks. Didn't use coolers and had very minor issues with the trans, never a failure. He eventually sold and now drives a 600hp+ Z and does extremely well.

Temps - I watch the engine oil on the HUD and transmission on the DIC, I keep the engine at 260 and the trans at 240. Any more than that and I start cool down laps.

StKnoWhere

A transmission tune helps a lot with shift response on earlier C6 but I don't know if helpful for the GS.

V4kerker

thisismyusername your Grand sport should have a trans cooler already, but it might not be enough cooling if your running 10/10th's.
I HPDE a C6 with a auto (base coupe) and my trans temps are 220-240runs close to what the engine coolant temp is.
Invest in a EOC and DOC first if your grand sport doesn't have them. I'm sure the auto grand sport is a wet sump engine and if you don't have a EOC that oil gets hot quick running 10/10th's. I've hit 290F before.

Us the sport mode (paddle shifters) when running HPDE forget drive mode it sucks on the track. One problem with the auto is coming out of a apex that's got a long hard braking zone going in. I can feel the torque convert doing it's thing. I think this is because the trans oil may all be going to the front end of the oil pan plus foamy oil. Not sure if the trans is losing oil to the torque convert during hard braking.

I've got over 70K on my 2007 C6 A6 and 15+ HPDE days with one trans fluid change.

Good Luck

thisismyusername

Thanks for the replies, I appreciate it. The Grand Sport is a 2013. Wish I still had the Z with the manual, but had to go to the automatic. I definitely won't be pushing it at even close to 10/10ths.

With the automatic transmission fluid, what temperature should it run in, and what is a bad temperature? Will the DIC warn me if it reaches a bad temperature?

Thanks!

ErnieN85

Trans temps are best around 180 however on track that is very hard to do. 240 is the highest I want to see
just get the biggest cooler you can fit in front of the radiator stack.
I'm using the biggest motor home cooler Advanced auto had it's specd for 28,000 lbs gross weight

Bluefire

I added a Setrab 25-plate aftermarket trans cooler. I was still seeing temps at 235 - 245 at the end of my third track session for that day.

I got tired of the fight and am in the process of converting to an MN12.
Best of luck to you.

MarkDFW

I've got an aftermarket torque converter and tranny cooler on my A6 grand sport and I see around 250 for tranny temps. So far, hasn't caused any issues. *knocks on wood*

I use redline for all fluids: oil, tranny, and diff.

Solofast

The use of a higher stall or "looser" torque converter for a road racing car is a bad idea. Not only is it harder to control weight shift on trailing throttle, but that type of converter generates more heat. As I said above, most of the heat generated in an auto trans is generated in the torque converter. If have to have an automatic, you want a "tight" converter that has less slip and generates less heat.

MarkDFW

Agreed. I plan on selling my car next year and buying a dedicated track car.

Bluefire

It really isn't that difficult/complicated.
Swap out the big parts (add the ones you don't have).
Add two pedals, two switches, and a shifter.
Swap 10 pins at the PCM connector.
Swap your tune file...

Viola You're done!

TKOGTO

When I started getting trans temps in the high 260s on my 2010 GS A6, I added a B&M Hi-Tek auto trans cooler (10"x7-1/2"x4" with 7" diameter fan) and ran the fluid thru the rad 1st. This worked only for a short time as well. After a while, I needed to run 2-3 cool down laps mid-session to prevent temps in excess of 270.

To lower the temps I have tried the following: a) removed the cover inside the side gills of the front right fender where the cooler was mounted hoping to increase flow out of the area behind it - no change b) relocated the cooler to the right front fog light area to get direct flow - no luck c) removed the fan from the back of the cooler thinking it may have been blocking the flow out the back. At the same time I removed the rad from the plumbing of the trans fluid - temps got worse. I will check the lines for some type of restriction and absent finding anything, will replace the smallish B&M with a large Setrab cooler (version 920 rated @ 35k - 50k BTUs).

Don't do what I did. Learn from my experience. Get the biggest Setrab that you can fit. As for fluid, I use Amsoil ATF.

blkbrd69

This is what I had to do.
http://forums.corvetteforum.com/auto...-course-t.html

mikeCsix

Anyone running a differential cooler? The auto doesn't come with one and the differential can generate a lot of heat the transmission has to absorb.

C66 Racing

This is the Dexron VI fluid that AMSOIL recommends for your automatic transmission:
AMSOIL Torque-Drive Synthetic Automatic Transmission Fluid (Product Code ATD1G)

This fluid does have a high quality synthetic basestock that should stand-up well to the heat of the track.

As for the diff cooler, after 10 years of racing in the SCCA, I finally broke down and put one in my 02 Z06 this past year. I think my diff has been running a lot hotter than I realized all these years. I feel much better having the cooler. I use DRM's unit.

More than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.