I watched your power flow video before this and even posted how nice it would be to see some information on the hydraulic system. Well lo and behold…….. I am going to continue to study until this makes more sense. I am a thirty (+) year Master Tech that has just recently decided to get into transmission repair/rebuild as aggressively as possible. Like most of the systems I have learned over the years, knowing the “theory of operation” (what does this part/system do and why) is key when not only diagnosing difficult issues, but also being able to see/verify proper assembly and operation. I don’t want to simply just replace what I think I should or what I’m told I should during a rebuild and then just assume the unit will work properly. I want to know as much about why and what as I can learn. I would love to build a couple of transmissions with you as an instructor!!! Thanks for making the videos. They really are helpful!!

Fantastic video on theory of operation. Really helps with diagnostic for a guy like me who is in the repair field but not necessarily the transmission repair side of things.

very helpful video... torque converter failure, 3-5rc rv was sticking and CSV#3 was as well... this explain why i had a delay in the 4th to 5th shift

Thanks buddy! This is probably the best learning tool on the 6l80 i have found.

This is full of really good 6L80 theory and info - thanks for laying it out.

Very good info

Many thanks.

Slightly off subject, GM Colorado 2014 6L40 does not engage Drive first gear and slips, but does engage if put in Manual first, where should I look please. No codes. Awesome video, THUMBS UP

Thanks for the awesome video! I wish I would have found this before I rebuilt my transmission. TCC failed on mine, and destroyed the pump. I did a complete rebuild and replaced the pump. Everything works great except for when it gets up to temperature, and only intermittently, I’ll get 3 - 4 pulses immediately after shifting into 2nd. It only does it occasionally, and only when it’s hot, so strange. I’ll have to rewatch your video a few times, and maybe I’ll have an epiphany. Thanks for the awesome content!

Here is what I find interesting about the 6L80 and 90. There is only one one-way clutch for first gear, which means that by default there should be engine braking in all other 5 forward gears. So am I right to assume, that when coasting, the TCM drops the converter feed pressure to a minimum, and if necessary, disengages the TCC, for maximum slippage, reminiscent to what it would be pressing the clutch on a manual? Likewise if the brakes are applied, that feed pressure would be immediately ramped up? If that is true, then the next question is, in an emergency braking - will it re-apply the TCC and the low/reverse clutch when it gets down to first gear?

this good learn

Well explain and seems your are automatic transmission specialist

Very very helpful video, what would cause slip once its selected a gear say 2nd or 3rd, moderate to heavy throttle input, is fine under say 50% but anything over that it begins slipping, been trying to work out whether maybe the pressure isnt anough to hold the clutches engaged, any advice or pointing in the right direction would be appreciated

Muy interesante contenido y muy agradecido Soy latino del sur de América (Colombia ) Sería muy importante suptitulos en español

Thanks for the video, does the TEHCM have pressure sensor to send the info to the scan tool or is it mechanical gauge test only?

Where can I get the fluid diagrams?

Where do find this interesant your information, to my, ilustracion learn it?

In the TCM TCC Desired Pressure tune I see it refers to PCA Pressure. Does anyone know what PCA Pressure is? I suspect it’s not the same at PCS Pressure.

Got to suscribe to Chanel!

Rebuld a 6l80 and in neutral range the truck moves in reverse slowly help please

I could really use your help ! I have a brand new GM 6L80 and it will not shift out of first gear. Goes into neutral or maybe slip until you let off the throttle then 1st gear returns. Tcm is commanding the shift but nothing is happening. What should I be looking at ? Also has a 2-3 second delay going into reverse.

I have a 2008 Escalade with a 6L80e that is having EXTREMELY harsh 4-5 shift under any load. Other than that, there is no slipping, flares, or anything. Logging shows no errors, and there are no codes. Does this sound symptomatic of a TECHM/valvebody issue, or more likely the transmission itself? Fluid is at proper level and not burnt, trans never gets above 145F. It's odd that only the 4-5 shift is affected and it's such a harsh shift that it wobbles the truck.

Hello, I am talented in repairing automatic gearboxes and car maintenance, and I am now looking for a job. Can you hire me

Hello boss

Dang I’m seeing 300 psi on 1st and second when shifting but then settles to 150. And she’s whinny so sure got a leak somewhere

The devils own design. Outrageously over engineered. Frightening just to look at. Better to take the bus.