Larsson

Thanks grumpy bear for the pm. I'll keep that tip in mind. You said that the problem is the jmbx torque converter. I put a heavy duty jmbx in my transmission(HDB85JMBX). Are the hd versions better or just as bad? Perhaps the heavy duty version usses a different torque converter clutch? This is what I'm going to do. Modify the transmission software and then drive it for 8000mls. Then drain the oil and see if there's debris or alu dust in the pan. If there is then I'm changing the torque converter with a sonnax upgrade.

Does sonnax sell those modified converters or must I buy a sonnax tcc kit and take it to a transmission company together with my bad torque converter? Or do you know other companies who sell "improved torque converters" for my 6L80?

I noticed that a lot of gm trucks (2014 and up) have seat heater problems. And that is such a problem that not even the dealers can (sometimes) come up with a solution. So I hope that someone smart can help me. I have a 2014 chevrolet silverado ltz with heated and cooled seats. The buttons work ok and the cooling feature works good but the heated seats don't. When I checked the voltage at the connector under the seat the first time there was no voltage present But the second time there was some action going on. I used a voltmeter and a testlight. At the low setting there was a pulsating voltage present. At the mid setting there was a higher and faster pulsating voltage present. But at the high setting there was nothing. Not even after a few tries starting the car. The heater elements in both seats measure the same resistance. So I think it's the bcm. Where is this bcm located? And when I replace it, does it need to be programmed?

So all the 6L80 transmissions have the bad torque converter clutch problem? And not just the early ones? But why didn't anyone in the aftermarket car parts business have developed a better torque converter for the 6L80? The company who did could earn millions of dollars. I don't hear that dodge or ford have such major transmission design flaws. I always been a chevy truck fan but isn't gm making it very hard for us not to buy a different brand of truck?

You said that the 14s and 15s don't have the torque converter clutch issue? Maybe I'm not so lucky then? Cause my transmission had a little film of alu dust in it. My truck is build in december 2013 but the transmission is build in 2015 (I think). What I'm meaning to say is: do I need to change the transmission software or is it ok to leave it like it is now? It drives like new now but I want to run the transmission way past 100000mls without rebuilding it every few years.

I've put the valvebody in the transmission and bolted everything back in the truck. Took it for a testdrive today. Now it shifts and drives like a dream! Even in v4 mode. I put in a HD B85JMBX of tc remanufacturing. Lets hope that a HD torque converter last a bit longer than a stock one. I'm thinking of changing the software of the transmission but I don't know somone who has the equipement to do this here in Holland. Is it duable to buy a softwareprogram and connector for myself?

Maybe I'm saying something stupid but does gm have an transmission software update to tackle this known problem? I found a video on YouTube which shows somone who has changed the transmission software with "HP tuners". (6L80E The real cause of failure and how to adress them). Is it a solution to the tcc problem?

Here is an update on how things are going with my tcc problem. The mechanic I took the truck to says that when he connects the diagnostic computer and pressurises the tcc the pressure drops within one second or so. He said it's a faulty tehcm but I don't believe him. A transmission control module (tehcm) is quite expensive and is working or broken, at least the solenoid is. So I did something I should have done earlier. If you want something done right, you have to do it yourself. So I took the tranny out again and inspected the whole thing. Replaced the pressure regulator valve with the transgo SK6L80 kit and inspected the oil pump. There was not much wear on the pump and the pressure regulator valve so I put my attension to the valvebody. Took the valvebody appart and put in sonnax o-ringed end plugs and a transgo 6L8CSTCC (clutch select valve and tcc regulator valve kit). But when I took out the tcc regulator valve the sping didn't come out. So I used a little hooked tool to get the spring out. But to my supprise the spring came out in 3 pices. I think that is the cause of my tcc issue. The tcc regulator valve was not working propperly due to a broken spring. And that's explains the pressure loss. I'm waiting for the 8 plastic checkballs to be dellivered this week and then I'm going to put it all back together and take the truck for a testdrive. I'll give you people an update on how things went.

Thanks for your reply. You give me some new things to check now. Today we went on a testdrive with a diagnostic computer and the mechanic thinks it's the techm. He suspects that a bad solenoid or pressure switch is the cause. April 6th we're going to ask a tranny guy for his opinion. Is it possible that the Pressure regulator valve has something to do with it? Or does this part has nothing to do with the torque converter? When we changed the tranny fluid, it looked quite normal. There was no dirt or alu dust in the oil. So I think the oilpump is ok. The old torque converter was probably good. But you got to start somewhere and it seems like the 6L80 converters are prone to break at 100000mls. My truck just did 85000mls.

Hi guys, I bought a 2014 chevrolet silverado 5.3 LTZ with the 6L80E transmission. When I keep the truck at a steady speed ,for example 35 m/h, the transmission keeps changing rpm. It 's constant changing between 1400 and 1200 rpm. When I drive at 50 m/h the rpm changes from 1600 to 1400 rpm. It seems that the torque converter clutch is constantly engages and disengages. I allready replaced the torque converter ,flushed the transmission and reset the computer. This didn't made a difference. Does anyone have an idea?