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Hi, wondering if anyone can help with a problem I have the transmission (4L65E) goes into hot mode but its not getting hot, I can see from HP Tuners that the over temp set point is at 130 deg and it ruins mostly around 70-80. It goes to hot mode at around 10 minute intervals on then off then on. I have changed the time it takes to set a hot mode with HP and it makes no difference always roughly ten minutes (not exactly but roughly from 7 mins to 15 mins). If I copy the shift points and TCC over from normal mode to hot mode then I dont actually notice that its doing it, but I am trying to get the cruise control working (its a conversion car 6.0 Ltr with 4L65E) and I know it will kick it out from cruise to hot when it happens so I need to get this fixed first.n Any information would be appreciated.  

If your talking celsius then 80 is normal. What are the symptoms you are feeling when its in hot mode?  

Yes thats what I'm saying the temps are normal yet it goes into hot mode. And the symptoms are whatever I make the difference between normal mode and hot mode,
Example if I make hot mode have no converter lockup, then when it goes into hot mode the converter doesnt lock up. Or if I change the shift points to very low speeds then it changes gear at very low speeds when its in hot mode, it just does what its programmed to do in hot mode. And as I stated above I can copy over the shift points and converter lock up speeds so that I cant tell any difference, but it will still be going into hot mode every 5-10 minutes and out again. The syptoms are not the issue, the issue is whats making it happen so I can fix it and then get cruise control working.
Can anyone else help ?  

i am taking that you have a scan tool to look at the live data readings...  can you take a snap shot of the live data..

copy and paste what you can get.. i can read the data stream and can usually diagnose thing by the values ..


engine cold.. not running..

engine cold idling..

engine at normal operating temp idling...

and a snap shot of when it defaults to hot mode...

you will also want to do this for the transmission data stream.. which is usually different than the Engine data stream when you set up the scan tool..   it asks for PCM, or TCM or ABS or SRS..  

i wonder... if you have possibly got some kind of restriction in the transmission cooler hoses..

what kind of transmission cooler are you running..  

in radiator .. in front of the radiator.. self contained with its own cooling fan..

what kind of radiator cooling fan are you running..   belt driven..  with a thermal fan clutch..   electric cooling fan..

what controls the radiator cooling fan..   the PCM?? or????

do you have a thermostat in the cooling system????


why am i asking this.. so i can figure out why your car truck hot rod, chainsaw  is doing this..

oh.. tell me you have not seen the small block chevy powered chain saw..  it does take 4 lumberjacks to hold it..  

Where are you getting the normal temp reading from? The computer or are you taking a temp reading from another source? As far as i know the computer uses the resistance on the temp sensor to  determine when to put the trans in hot mode. It seems to me if  your getting your temp reading from the same source as your program then it must be a software issue. I  never worked with any tuner programs myself.  

440t4 the temps are being taken from the computer.

Wayne (blocked lines) - no restiction in lines (new braided)
     (trans cooler) - initially air-cooled only in front of radiator but I thought the problem may be that the fluid was undertemp and there may be a "too cold" mode thats combined with the hot mode, so I got another radiator with inbuilt trans cooler and ran the extra air one as well like many people do but it made no difference.
     (radiator cooling) - I have one large fan controlled by the computer, it comes on at temps set in computer and runs up faster % as hotter when needed and works properly, the motor doesnt get hot and I have a 180 deg stat in it.

The attachments are snapshots of runnning on freeway just before and after it goes hot, Note that at that time 'hot mode' wouldnt allow 4th gear so thats what you see when it goes to hot mode.

OK it seems I cant attach a pic of the screenshot , anyone know ?  

I don't know if this is possible but do you have the option to set the limits in Fahrenheit or celsius? Is it possible you have the hot setting at 130 degrees fahrenheit?  

this should work



and also

 

try again
 

hot mode

 

last try of hot mode

 

i can see that there is a slightly different problem... and  will have to have you check it out..


why is the transmission turbine RPM and the trans input shaft RPM exactly the same.. and very slow...  instead of matching engine RPMs or close to it.. and in forth gear.. there should be a difference.. and also a difference in trans calculated gear ratio...

something is wrong..

when the sensors are not reading properly.. the computer will default to a fixed number..

you are going to need to go over each transmission sensor circuit and verify the are outputting the proper signal...  and not locked into default..

more to come...  

Yea that turbine/input shaft rpm data cant be right.Maybe the freeze frame data from 1st and 2nd would help also.What year is the trans from? They didn't have input sensors before 2007-2008. Does the computer and harness match the trans?  

Yes the transmission does not have an input speed sensor on it, I wanted a transmission with one but could not get hold of one at the time (I'm in Australia) so the guy that did the wiring harness for me got a patch put in the computer programme (using EFI Live as HP Tuners doesnt have that capability) that would suposedly fix it up ??