lyonsac4242

Hey guys, I'm just starting to get into road racing and trying to learn as much as I can to stay safe and keep my car in one piece. I've done 3 event now (2 autobahn in Joliet IL and 1 at Blackhawk Farms by Rockford). During my 2nd event I got the warning message "high trasmission temp, idle engine." I proceeded to have eurosport change the fluid and did not see the message for the rest of the day. It was a 90 degree sunny day. Yesterday I was at Blackhawk and towards the latter part of the day I saw the message again. I did a slower lap in higher gears and drove around for a while to cool it off. It is fine, but I am disturbed to see that warning again.

I have a 05 Z51 6sp manual. I believe my car is equipped with an engine and transmission cooler since it is a Z51 equipped car. So questions:
1. Have any of you seen this message before?
2. How many of you have installed upgraded transmission/differential coolers?

Advice, thoughts?

FYI, I was pushing the car reasonably hard, but only got close to redline on 1 straight before shifting to 4th gear. I was also working on heal-toe down-shifting, but I didn't really over-rev... Thanks in advance.
Scott

rustyguns

WHAT WAS YOUR ENGINE TEMP WHEN TRANNY LIGHT CAME ON?

I JUST SLOW DOWN FOR A BIT THEN DRIVE IN A HIGHER GEAR TO KEEP IT COOL ON HOT DAYS. BUT I PUT A LINGFELTER OIL COOLER ON AND ENGINE TEMPS DROPPED AND SO DID THE TRANNY. DO YOU USE WATER WETTER WITH JUST H20 IN UR RADIATOR? THAT HELPS DRAMATICALLY !

SYNTHETIC OILS HELP TOO

I THINK MOST OF THE HEAT IS FROM THE ENGINE AND EXHAUST. NOT CHANGING GEARS SO KEEP PRACTICING

lyonsac4242

My oil temps only topped out at 273 when they got to 282 earlier on a hot day. I have seen some people say use water in radiator with water wetter. Do you know how that helps? I plan on putter on a radiator with oil cooler/trans cooler on in the off-season (dewitts). Anyone else get this warning though? I will change the tranny fluid before I go out again. Redline or Amsoil the best? Also, if I put just water and water wetter in the radiator before track events, I would have to change that back to regular coolant for normal driving right? That would be kind of a pain in the rear to do before every track event. But if it helps cool things off that much...

rustyguns

you dont need prestone if the temps are above freezing and even straight water can take freezing temps for an hour or so without hurting the car. if its already freexing in your town you can run 10 percent antifreeze that wiil give you plenty of protection until winter sets in. FYI the water wetter has lube and anti rust additives

the way it works is, water conducts heat better 25 times or more than coolant. so radiator works a LOT more efficiently! i dropped 20 degrees with just water wetter !

redline and amsoil are both very good. i use royal purple syncro max it is good too any of those 3 will work great!

im gonna go redline the next change

gkmccready

I've run at Thunderhill on 105+F days and hit 300F on the oil. I've never seen a tranny over temp warning. Thunderhill is primarily a 3rd/4th gear track, though. (06 Z51)

rustyguns

it the redlining in 2nd repeatedly that gets it hot ! but it is so much fun ! torque baby ! torque

AU N EGL

Which AutoBaun? North or South ?

Autobaun seems to me as a technical track, not really a high speed track.

In my little time, about 70 laps one day on south, it was mostly a 3 gear track. One corner was down to 2nd, and the front straight for 100 feet was 4th gear and the back straight into 4th gear.

Blackhawk is also a technical track.

Not sure if the C6Z51 manual has the transmission cooler.

lyonsac4242

It was on the full track... There are 3 straights where I got into 4th gear for a touch, getting up to 112 to 116, I never dropped to 2nd as I feared I would over use the torque and spin. I saw that DRM has a tranny/diff cooler set up for around $1600 for both, but i believe that is for C5's. LG has a set up for like $3600. I will have to contact some of the vendors and see what they have available and what they recommend. I'll try the water wetter next time I am out and see how that works for the oil temps. Gotta change out the track pads and wash her down today. I will peak underneath and try to locate the tranny cooler.

Wayne O

I don't claim to be an expert but I run my car in Arizona where it does get hot. Even pushing the car hard for 20 minute sessions I've never seen a transmission temp warning (and I certainly push high RPM's). I use coolant, Royal Purple tranny fluid and Mobil 1 motor oil. I change motor oil frequently believing my engine runs cooler with fresh, clean motor oil. I change my transmission fluid about once a year.

Water Wetter might help but I'd definitely suggest you change your transmission fluid and your motor oil before hitting the track again.

C66 Racing

Can't directly speak to the Z51, but tranny high temp warnings are very common on a stock C5 z06 (no tranny cooler). I recommend changing your fluid with a good synthetic. I recommend this (which is a Dexron III fluid and is recommended by AMSOIL for your tranny):
AMSOIL Torque-Drive Synthetic Transmission Fluid (stock code ATD1G)

As mentioned above, water transfers heat better than anti-freeze. In my track car I use a 25% anti-freeze, 75% water mixture with one bottle of Water Wetter. That will help coolant temps a little, but not much. To really get coolant temps down, I had to go to a bigger aluminum radiator.

rustyguns

Hey Wayne! you don't count! you have so much horsepower you only have to use 1/2 throttle!

You have to have one of the sweetest Corvettes in AZ !!!!!

lbarnard

I had the high temp on my transmission and switched to Redline Synthetic high temp ATF. Never came on since. I use Redline High temp synthetic gear oil as well. I change both once a year since I do more than 7 track events a year.

rustyguns

when you do the Dewitt radiator it should solve all your heat problems

We have one guy in our club that has all the coolers and radiators that can be put on the Corvette ( he owns a shop ) and he still overheats...but he sets new track records every weekend too

so don't feel too bad

i checked my radiator and it was clogged with tumble weeds and packed with dirt. cleaning that made a huge difference too. the previous owner must have lived in the boonies. the radiators are big vacuums and need to be cleaned regularly

lyonsac4242

I was running on new Royal Purple Motor Oil, new Redline Differential fluid and tranny fluid that only had 1 track day on it. Will upgrade tranny fluid to Redline/Amsoil, then add water wetter. Any other input is still appreciated. Do high oil temps lead to high driveline temps? Still learning...

rustyguns

yup! hot engine makes everything hot!

96CollectorSport

I would be changing your diff fluid more often than you change your tranny fluid. I do matinance on several track cars with the LGM and DRM coolers and even with the coolers I would change the diff fluid after every 2 events, the tranny fluid seems like it lasts closer to 6 events before it needs to be changed.
If you really think about it there really is no reason for the tranny to get that hot, there is no/little friction in the tranny compaired to the diff, if you add a diff cooler I think you will see your problem go away.
The Dewitt's rad is a great idea, I've split a side tank on the factory plastic/aluminum rad (at Autobahn actually) it's no fun and almost caused me to spin. The DeWitt's radiator offers twice the cooling surface that the stock radiator does, plus they really are a direct fit.

0Vector Vette

Scott,
Your Z51 car has both an oil cooler and trans cooler running into the radiator. That is where the corelation of higher temps is from. Racing/tracking causes all the temps to get higher. Water, oil, and trans fluid all go to the same source for cooling, therefore you need a better cooler. Installing a DeWitts radiator should solve your trans temp problem. The fluids you are using are all good performance products, no need to change from them. Running water with a little water wetter or anti-freeze does bring temp down a little, that is what we do on the racecars. You don't need to change that to run on the street. You do need to change it before winter though. I can get and install the DewWitts radiator for you if you are interested.
Robert Finlayson
Performance AFX Motorsports

02impactblue

I had a c6 z51 and tracked it as often as possible for 2 years (30+ days). Several track events were at vir in the dead of summer and I never had tranny temp warnings. I have been accused of very aggressive driving but its the only way to make up the 100hp difference from the z06 crowd. In other words the car was never babied. Something else is going on. You wouldn't happen to be tracking the car with a bra on would you? I have a friend running a bra with fine mesh which was just enough restriction to cause water overtemp alarms. Cut the mesh out and temps dropped 20-30 degrees.

lyonsac4242

nope, no bra. weird. Going to try to get out to track 1 more time this year. We'll see if it comes on again. Then VectorVette and I are going to go with the dewitts...