89gta383

iTrader: (5)

I have a 4L80E from a local builder who has done many 4L60E and 4L80E trans for cars all over the country. He has stages of performance builds like most trans shops that do hi po work. I got a stage 1 trans from him, later model, supposed to be good to 8-900 hp, but I am having problems keeping the fluid temp cool. It has a 3800 stall FTI lockup triple disk converter.

I have a tru-cool 40k external cooler on it now with a 1300 cfm 10" fan behind it and the trans temps still go above 210 degrees. I only have about 20 miles on this trans total as i don't drive it far enough to risk running the temps too high. I about a 3-5 mile light throttle drive loop, the original trans (1 below) got up to 265 degrees just driving around part throttle and idling in the driveway. The temps never stabilized, always climbed higher. I ran this same b&m stacked plate external cooler only deal on my 700r4 and 4L60E, but never had a way to monitor fluid temps, so i don't know if those trans had issues. The cooler is inbetween the intercooler and radiator fan with a fan behind it that runs all the time on a switch.

i am getting the trans fluid temp from the 411 LS1 pcm data stream and verifying the temp with an infared temp gun pointed to the bottom of the trans pan and cooler and cooler fittings. The infared temp gun is within 2 degrees of the pcm fluid temp sensor in the data stream. The cooler and lines show about 118-120 degrees when the car is fully warmed up. Fluid is always bright red and smells new.
Here is what has happened so far:

1-got original trans from him and put it in, temps got up to 265 degrees with my old b&m 6x11 stacked plate cooler with -6an lines from the trans straight to the cooler. Put a fan behind the b&m cooler with no luck, temps kept going higher.

2-took trans out and sent it back to him and converter back to FTI. FTI cut it open and said it looked new inside. When i put this trans in, i got .091 clearance between the converter pad and flexplate and 1/8 is the minimum clearance you should run. I have heard anything from 1/16 to 3/16 is fine, so i ran it. FTI took out a .030 shim from the converter to move the hub lower in the converter to give me the 1/8 clearance. trans guy pulled it apart and said the thrust washer showed some signs of heat, but nothing else. He thought the tight clearance between the converter and flexplate was the issue and enlarged the fluid feed in that area of the pump.

3-put trans back in and same issues, temps just climb. i changed to new -6an push lock hose and ran the fluid threw the radiator and then thru the external cooler thinking the fluid wasn't out of the trans long enough to cool down. just went for a drive and temps went up at a slower rate, but still got up to 207 before i got back to the house and shut it down. coolant temps never went higher than 187 on my 13 mile drive loop

I need to hear from trans am owners with 4L80E's on if you are having fluid temp issues? I am still thinking the trans has some sort of internal issue, but he has all new bushings and parts in it and swears it is a cooler flow/cooling issue on my part. Need help.

IROCZ1989

iTrader: (1)

You have the 40k true cool 1.5 thick plate? Find a different spot for it. It's most likely starving for air being sandwiched between 2 heat exchangers. Derale makes some nice coolers with and without fans simaler in design to the setrab units which are good but expensive. I never had an issue with a 700r4 overheating. 4l80 is bigger which means more metal to soak heat. Do you have it plumbed inline with the stock cooler?

IROCZ1989

iTrader: (1)

I have the H7B trucool. Simaler to the B&M coolers. Never had an issue with these.

89gta383

iTrader: (5)

I have the tru-cool LPD4739 which looks like a damn radiator at 22 x 8.5 x 1.25 in size. I took the fan from behind the cooler and put the cooler up against the radiator with 1-2 space between both. there is about 10 inches of space between the intercooler and trans cooler and the trans cooler is right in the path of the air flow from under the car. I even swapped in a stock converter to see if the FTI converter was the issue and temps still rise with no end in sight until I shut off the car. I even started emailing sonnax tech support about possbile causes after i found this tech article:

https://www.sonnax.com/tech_resource...tive-clearance

Trans builder is building me a new trans so hopefully there is something wrong inside this trans. Don't know what else it could be,

Camaro86IrocZ

iTrader: (1)

Probably unrelated, I was just recently reading while surfing the net that if the outlet and inlet cooler lines are somehow hooked reversed to a plate cooler that it may create excess heat as the design of the internal cooler bypass just sends fluid back..

IROCZ1989

iTrader: (1)

So he will tell you if its negative clearance and he made a mistake? Hope you get this figured out.Something like this you shouldn't even have to be worried about. That cooler is massive and should be able to cool that no problem. Good luck and update when it figured out.