Update: Before I left for work this morning, I had a chance to mess around and troubleshoot a little more. If I pull the transmission ignition fuse (19), the truck will move forward with no issue. I have no option to manually shift however - D only. Fuse back in, no movement. I think my first course of action will be to replace the two solenoids and put in new fluid/filter and see if there is any change.

 

You have anything you can scan codes with? That would be my first course of action instead of guessing and tossing parts on it.. To me pulling the fuse indicates that the controller for the trans is faulty and pulling the fuse is putting it in limp mode giving basic trans functions. To me if solenoids were bad it would not work at any time fuse or not.

 

I have a regular OBD2 reader, but I'm code free.

 

Ok, I fixed my problem myself in the driveway for $115. Shops wanted to rebuild or replace. I have very little mechanical experience outside of changing my oil and spark plugs. If you are smart enough to unscrew bolts and have a lot of patience, you can do this job yourself and save possibly thousands.

I wanted to edit the topic name but it does not let me. If any moderator could change 4L60E to 6L80E, that would be great. If it isn't changed, I'll repost so that others can find this information in the future. I read a list that said my 2010 Sierra had a 4L60E but it is in fact the 6L80E - if you have 6 gears, you almost definitely have this transmission on a 1500 truck from this era (the heavy duty trucks have a 6L90E).

The Problem
Suddenly, you have no forward gears in your vehicle. No signs of transmission issues before this. Your truck works strong in reverse, but no forward at all. It just feels like you're in neutral.

The Short Term Way to Move Your Truck
I read a lot of posts that scared me about how the planets and other expensive sounding parts of my automatic transmission were likely dead. They were all wrong. I was able to get my truck to move forward by removing fuse 19 under the hood (TRANS IGN 01). When you remove the fuse, it will force full hydraulic pressure and you will get what I believe is 3rd gear to move forward. This can at least let you limp the truck around to where you can work on it. Once you have the truck in a spot that you're going to work on it, I recommend putting the fuse back in so that you don't forget later. If you remove this fuse and don't get a forward drive back, you may have a different issue but I cannot say for sure.

The Cause & Setup
The problem turned out to be a deformed check ball in the valve body plate. Before I did this project, I had never opened a transmission in any way so I'm going to explain it in detail for a layman like me.

Right above the oil pan in your transmission is the valve body, which has the TCM connected to it on these trucks. The 6L80E transmission has no external solenoids to replace so disregard that cause when you read it on other forums.

The valve body has two pieces, upper and lower and is held together with a series of bolts that are metric. Between the two pieces is a "plate" that allows fluid to move between the upper and lower parts of the valve body. This is how your automatic transmission changes gears. Check ball #1 will have shrunk to about half of its factory size and gotten stuck in a hole in this plate, preventing fluid from moving into this part of the valve body and being able to move into your forward gears. To remove the valve body, you must have an E12 torx socket. You also will have a hard time getting the oil pan off your transmission because of the exhaust that runs directly underneath it. I was able to use a piece of rebar wedged between my floor jack and the crossmember to pry it down enough to gain clearance. Be careful not to hurt yourself.

To do this job, I used:
•A ratchet set with metrics ranging from sizes 7 through 11
•An E12 Torx socket, I bought mine at advance auto for about $5. You need to this to remove the 6 special bolts that fasten the valve body to the transmission.
•A jack
•Pieces of wood to place under the tires of the truck after jacking it up so that I had plenty of clearance to work under it without worrying about moving around jack stands. Plus it allowed me to free my jack up to get leverage on the exhaust. You may have another solution but make sure that it is sturdy, safe, and gives you proper clearance to do this job.
•New check balls. I purchased the "Sonnax Valve Body Check Balls 10000-08" (0.250 in. diameter) from Summit Racing. They shipped in two days and are perfect. You may be able to get these from a local transmission shop for a $5 bill if they have a bunch laying around.
•7 Quarts of Dexron VI transmission fluid (6, not 4!!)
•A new transmission filter
•Narrow necked funnel

Step 1: Starting the Job & Dropping the Pan

As mentioned earlier, I recommend getting your truck elevated on a sturdy surface that you trust. I used 2x4 cut into 2 foot lengths and used 12 of them each under the wheels to lift the truck 8 inches. It helped a lot. Make sure that you have your parking brake on.

Working with the pan on this truck is the worst part of the job. If you don't have a lift and a lot of tools that someone who works on cars every day has, wear clothes that you never want to see again. You will likely be taking a shower in transmission fluid. There are about 18 bolts on the pan that need to come out, sized 10 or 11 I believe. You must get leverage on the exhaust to get the back part of the pan out. It looks like you can easily get it out - I thought the same but everyone else on the internet was proven right. Drop the pan, drain the oil into a bucket or catch, and remove the pan. Check for metal - mine was actually very clean which only reaffirmed my thought that there was no serious mechanical damage to the transmission. Save the gasket, it is reusable. Set the pan aside for later, you won't need it again until the project is over.

Remove the transmission fluid filter. Just jiggle it and pull it downward.

Step 2: Removing the TCM connector

The electrical connection for the TCM is found above the rear passenger side of the pan. First, pull down the white tab on the under side of the pan. This releases the connection above. Then, push out the other white tab on the connector above the pan. The way it works is that the white tabs keep the coupler firm so that it cant move. You need to release the white tabs, then rotate it upward and it will eventually pull out. DO NOT TRY TO REMOVE THE ELECTRICAL CONNECTOR WITHOUT RELEASING THE TABS.

There are actually two plastic pieces at the connector - an "inner" and an "outer". The "inner" twists in to the tcm and is just a piece of plastic. The outer has a wire harness and is where the actual TCM electrical connector is. You want to remove the outer connector, but the inner connector came out with mine as well. That's ok, you can reset it later. Just be careful not to break anything, this is the hardest area to work while you're laying on your back and can't see above the pan.

Step 3: Removing the Valve Body
This part is pretty straight forward. There are 6 E12 torx bolts - 4 are on the metal part of the valve body and 2 are on the TCM. They look weird and you'll notice that they stand out from the other metric bolt heads. These hold the valve body to the transmission so once you remove them, the valve body can fall straight down. It isn't that heavy, maybe 15-20 pounds, just be careful not to drop it. Treat the valve body like it's a million dollar egg that you don't ever want to break. Also, make sure that you are careful with the metal and plastic shifting mechanisms. You don't need to do anything special to them while removing the valve body because they'll simply slip out of their spots when you remove it. I found this simple guide that helped me know what was coming up: http://www.150tunes.com/gallery/albums/ ... emoval.pdf

Step 4: Disassembly of the Valve Body, Checking the Plate, and Reassembly
This part is easy, but make sure that you are organized and remember where every bolt goes back in. There will be a good deal of fluid still in the valve body so prepare for a mess. Simply remove every bolt and device from the outside of the valve body, remembering where each goes. I watched a good video of someone doing it beforehand to gain some confidence:

At that link, you can actually see that he's looking for the same thing. At 4:59, he removes the plate and shows where the check ball gets stuck. Pop the check ball out of the plate and replace that check ball's spot with your new one. I also replaced the other 6 because I bought a 10 pack, but I suppose you could simply do the one that was stuck.

Put the valve body back together as you took it apart. There are probably torque specs but I'm an idiot that didn't look them up so I just made sure they were hand tight without going crazy. Someone will probably verbally berate me for this. None of the bolts on my valve body required much effort to loosen by hand.

Step 5: Put It All Back
Putting it all back is basically just doing what you did before in reverse. Make sure that you get the valve body back up in its spot nice and tight, no crooked bolts.

Once you have the valve body remounted, reconnect the TCM electrical connector. You will know that it is reconnected when you can push the white tab back up. DO NOT FORCE THE WHITE TAB. Funny enough (not at the time), this was the hardest part of the job for me. It took me maybe 30-45 minutes to get it properly reconnected. Maybe you'll get lucky, just be persistent and know that you can get it back in there. Once that white tab underneath pops back up, you'll know that the inner connector is right and you can twist the outer connector on. This video will help you understand how the connector works:

BEFORE you start to put your pan back on, I suggest hopping in the cab, putting the key in, and seeing if you get a line under your shift display on your dashboard. If you don't see the gear selection line under P R N D M, it means you probably did not reconnect the TCM properly. This happened to me the first time and I had to go back under and play with it more. It will be much easier to do this before you put the pan back on and start adding fluid.

Put your new filter in. Some people change the seal ring but I didn't really see a reason to, it seemed fine and I was fighting against the sun going down. I just put the new filter up in there. This is another thing I'll probably be berated for.

Put the pan back on, make sure the gasket is seated correctly, tighten it up. Do not over tighten your pan.

Step 6: New Fluid & Crossing Fingers
Go to the front of your truck, take out your transmission dipstick which is located in front of the passenger side window, and put your funnel in the tube. Start filling it with your transmission fluid. Mine took about 6 qts, I grabbed 7 quarts just in case I needed to add more.

I started the truck up after about 3 quarts to see if it would move forward at all. I crossed my finger, put it in drive, and it moved forward. Hooray! Once it moved a few inches, I stopped and filled up the rest to the proper spot marked on the transmission dipstick.

NOTE: For me, the shift selection started in the wrong spot, R, when I turned the truck on but it was physically in the park position. I simply moved the shifter forward to the reverse spot and then back to park and it corrected itself.

Debriefing
Transmission shops wanted to rebuild and replace. We're talking about $1000-4000 depending on what transmission you have put in and labor costs. Then, they remove the check ball from your transmission and turn around and sell it because it's perfectly fine otherwise.

The way that I did it cost me $99 for the 7 quarts of fluid and the filter, $5 for the E12 socket, and about $10 for the check balls shipped. I personally prefer to put in my own labor and effort in exchange for only spending $115 compared to paying a shop thousands after telling me the transmission is shot. Plus, when you're done, you feel like a legend. Good luck - if you ever have any questions feel free to message me and I'll do my best to try and help you!

 

Ok, I fixed my problem myself in the driveway for $115. Shops wanted to rebuild or replace. I have very little mechanical experience outside of changing my oil and spark plugs. If you are smart enough to unscrew bolts and have a lot of patience, you can do this job yourself and save possibly thousands.

I wanted to edit the topic name but it does not let me. If any moderator could change 4L60E to 6L80E, that would be great. If it isn't changed, I'll repost so that others can find this information in the future. I read a list that said my 2010 Sierra had a 4L60E but it is in fact the 6L80E - if you have 6 gears, you almost definitely have this transmission on a 1500 truck from this era (the heavy duty trucks have a 6L90E).

The Problem
Suddenly, you have no forward gears in your vehicle. No signs of transmission issues before this. Your truck works strong in reverse, but no forward at all. It just feels like you're in neutral.

The Short Term Way to Move Your Truck
I read a lot of posts that scared me about how the planets and other expensive sounding parts of my automatic transmission were likely dead. They were all wrong. I was able to get my truck to move forward by removing fuse 19 under the hood (TRANS IGN 01). When you remove the fuse, it will force full hydraulic pressure and you will get what I believe is 3rd gear to move forward. This can at least let you limp the truck around to where you can work on it. Once you have the truck in a spot that you're going to work on it, I recommend putting the fuse back in so that you don't forget later. If you remove this fuse and don't get a forward drive back, you may have a different issue but I cannot say for sure.

The Cause & Setup
The problem turned out to be a deformed check ball in the valve body plate. Before I did this project, I had never opened a transmission in any way so I'm going to explain it in detail for a layman like me.

Right above the oil pan in your transmission is the valve body, which has the TCM connected to it on these trucks. The 6L80E transmission has no external solenoids to replace so disregard that cause when you read it on other forums.

The valve body has two pieces, upper and lower and is held together with a series of bolts that are metric. Between the two pieces is a "plate" that allows fluid to move between the upper and lower parts of the valve body. This is how your automatic transmission changes gears. Check ball #1 will have shrunk to about half of its factory size and gotten stuck in a hole in this plate, preventing fluid from moving into this part of the valve body and being able to move into your forward gears. To remove the valve body, you must have an E12 torx socket. You also will have a hard time getting the oil pan off your transmission because of the exhaust that runs directly underneath it. I was able to use a piece of rebar wedged between my floor jack and the crossmember to pry it down enough to gain clearance. Be careful not to hurt yourself.

To do this job, I used:
•A ratchet set with metrics ranging from sizes 7 through 11
•An E12 Torx socket, I bought mine at advance auto for about $5. You need to this to remove the 6 special bolts that fasten the valve body to the transmission.
•A jack
•Pieces of wood to place under the tires of the truck after jacking it up so that I had plenty of clearance to work under it without worrying about moving around jack stands. Plus it allowed me to free my jack up to get leverage on the exhaust. You may have another solution but make sure that it is sturdy, safe, and gives you proper clearance to do this job.
•New check balls. I purchased the "Sonnax Valve Body Check Balls 10000-08" (0.250 in. diameter) from Summit Racing. They shipped in two days and are perfect. You may be able to get these from a local transmission shop for a $5 bill if they have a bunch laying around.
•7 Quarts of Dexron VI transmission fluid (6, not 4!!)
•A new transmission filter
•Narrow necked funnel

Step 1: Starting the Job & Dropping the Pan

As mentioned earlier, I recommend getting your truck elevated on a sturdy surface that you trust. I used 2x4 cut into 2 foot lengths and used 12 of them each under the wheels to lift the truck 8 inches. It helped a lot. Make sure that you have your parking brake on.

Working with the pan on this truck is the worst part of the job. If you don't have a lift and a lot of tools that someone who works on cars every day has, wear clothes that you never want to see again. You will likely be taking a shower in transmission fluid. There are about 18 bolts on the pan that need to come out, sized 10 or 11 I believe. You must get leverage on the exhaust to get the back part of the pan out. It looks like you can easily get it out - I thought the same but everyone else on the internet was proven right. Drop the pan, drain the oil into a bucket or catch, and remove the pan. Check for metal - mine was actually very clean which only reaffirmed my thought that there was no serious mechanical damage to the transmission. Save the gasket, it is reusable. Set the pan aside for later, you won't need it again until the project is over.

Remove the transmission fluid filter. Just jiggle it and pull it downward.

Step 2: Removing the TCM connector

The electrical connection for the TCM is found above the rear passenger side of the pan. First, pull down the white tab on the under side of the pan. This releases the connection above. Then, push out the other white tab on the connector above the pan. The way it works is that the white tabs keep the coupler firm so that it cant move. You need to release the white tabs, then rotate it upward and it will eventually pull out. DO NOT TRY TO REMOVE THE ELECTRICAL CONNECTOR WITHOUT RELEASING THE TABS.

There are actually two plastic pieces at the connector - an "inner" and an "outer". The "inner" twists in to the tcm and is just a piece of plastic. The outer has a wire harness and is where the actual TCM electrical connector is. You want to remove the outer connector, but the inner connector came out with mine as well. That's ok, you can reset it later. Just be careful not to break anything, this is the hardest area to work while you're laying on your back and can't see above the pan.

Step 3: Removing the Valve Body
This part is pretty straight forward. There are 6 E12 torx bolts - 4 are on the metal part of the valve body and 2 are on the TCM. They look weird and you'll notice that they stand out from the other metric bolt heads. These hold the valve body to the transmission so once you remove them, the valve body can fall straight down. It isn't that heavy, maybe 15-20 pounds, just be careful not to drop it. Treat the valve body like it's a million dollar egg that you don't ever want to break. Also, make sure that you are careful with the metal and plastic shifting mechanisms. You don't need to do anything special to them while removing the valve body because they'll simply slip out of their spots when you remove it. I found this simple guide that helped me know what was coming up: http://www.150tunes.com/gallery/albums/ ... emoval.pdf

Step 4: Disassembly of the Valve Body, Checking the Plate, and Reassembly
This part is easy, but make sure that you are organized and remember where every bolt goes back in. There will be a good deal of fluid still in the valve body so prepare for a mess. Simply remove every bolt and device from the outside of the valve body, remembering where each goes. I watched a good video of someone doing it beforehand to gain some confidence:

At that link, you can actually see that he's looking for the same thing. At 4:59, he removes the plate and shows where the check ball gets stuck. Pop the check ball out of the plate and replace that check ball's spot with your new one. I also replaced the other 6 because I bought a 10 pack, but I suppose you could simply do the one that was stuck.

Put the valve body back together as you took it apart. There are probably torque specs but I'm an idiot that didn't look them up so I just made sure they were hand tight without going crazy. Someone will probably verbally berate me for this. None of the bolts on my valve body required much effort to loosen by hand.

Step 5: Put It All Back
Putting it all back is basically just doing what you did before in reverse. Make sure that you get the valve body back up in its spot nice and tight, no crooked bolts.

Once you have the valve body remounted, reconnect the TCM electrical connector. You will know that it is reconnected when you can push the white tab back up. DO NOT FORCE THE WHITE TAB. Funny enough (not at the time), this was the hardest part of the job for me. It took me maybe 30-45 minutes to get it properly reconnected. Maybe you'll get lucky, just be persistent and know that you can get it back in there. Once that white tab underneath pops back up, you'll know that the inner connector is right and you can twist the outer connector on. This video will help you understand how the connector works:

BEFORE you start to put your pan back on, I suggest hopping in the cab, putting the key in, and seeing if you get a line under your shift display on your dashboard. If you don't see the gear selection line under P R N D M, it means you probably did not reconnect the TCM properly. This happened to me the first time and I had to go back under and play with it more. It will be much easier to do this before you put the pan back on and start adding fluid.

Put your new filter in. Some people change the seal ring but I didn't really see a reason to, it seemed fine and I was fighting against the sun going down. I just put the new filter up in there. This is another thing I'll probably be berated for.

Put the pan back on, make sure the gasket is seated correctly, tighten it up. Do not over tighten your pan.

Step 6: New Fluid & Crossing Fingers
Go to the front of your truck, take out your transmission dipstick which is located in front of the passenger side window, and put your funnel in the tube. Start filling it with your transmission fluid. Mine took about 6 qts, I grabbed 7 quarts just in case I needed to add more.

I started the truck up after about 3 quarts to see if it would move forward at all. I crossed my finger, put it in drive, and it moved forward. Hooray! Once it moved a few inches, I stopped and filled up the rest to the proper spot marked on the transmission dipstick.

NOTE: For me, the shift selection started in the wrong spot, R, when I turned the truck on but it was physically in the park position. I simply moved the shifter forward to the reverse spot and then back to park and it corrected itself.

Debriefing
Transmission shops wanted to rebuild and replace. We're talking about $1000-4000 depending on what transmission you have put in and labor costs. Then, they remove the check ball from your transmission and turn around and sell it because it's perfectly fine otherwise.

The way that I did it cost me $99 for the 7 quarts of fluid and the filter, $5 for the E12 socket, and about $10 for the check balls shipped. I personally prefer to put in my own labor and effort in exchange for only spending $115 compared to paying a shop thousands after telling me the transmission is shot. Plus, when you're done, you feel like a legend. Good luck - if you ever have any questions feel free to message me and I'll do my best to try and help you!

That didn't fix mine. I still don't have forward. I checked the valve body and check plates and check balls.

 

Thank you for the spot on directions how to changes the plastic bearings in the valve body.
I didn't get a chance to listen to the gmc before my ex-wife new husband took the tranny pan and filter out.
After following your instructions and putting the tranny back together. Well low and behold! Same issue accept I get to listen.
The tranny will go into reverse and move with full power. Once I put it into drive you can feel the tranny engage but when you give it gas, it feels like the brake calipers on the front are locked up. The motor revs up with no forward power. There's also a loose crackle sound in the front part of the tranny.
I'm think the torque converter but then I'm think a band.
Any help would be great.
Thanks,
Bill McGrath

 

Hi Bill,

Unfortunately, I can't speak to what you're experiencing and am not an expert on transmissions. What I ended up doing in my directions has lasted me until now without issue, but it sounds like you might possibly be stuck in a low gear?

I recommend doing the same thing I did when trying to track my issue down. A LOT of Google and Youtube searches as you continue to diagnose and troubleshoot the problem may lead you to where you need to be. Spending some time in "Youtube University" has saved me tens of thousands at this point, so I'm hoping that you're lucky and able to find the problem. If you do, you should come back and post it in this thread to help others in the future as well. Good luck!

 

Great to hear you got your issue fixed.

Sometimes on the transmissions the bands inside will burn up, torque converter can be a cause but that's usually hard jerky shifts kind of like a thump into gear at times, control modules can go bad the computer for the trans could get a spec of dirt on it somehow from road grime or whatever and cause many issues, I would take a 6L80E over any 8 or 10 speed any day at least I know the 6 speeds are going to hold up a little better.

 

Thank you for taking the time to write this up! Glad you got it fixed.

 

Thanks for this detailed symptom and diagnosis description. It sounded as if you were talking about my truck. I followed it step by step and sure enough 1 check ball was half the size of normal. For $100 (including cost of new fluid and filter) I am back on the road. Thanks guys!

 

Unfortunately for me, this didn't work for me. I did watch the video and drop the valve body to inspect the check ball. Mine were normal. Had the exact same symptoms as the OP. When I removed trans fuse, it will go forward. I think I might have a cracked 1234 piston. Anyway, it's at the mechanic now for them to tear down as I don't have the tools and know how to do a rebuild.

 

Ralphis i cant thank you enough. your post saved my job and basically everything . i simply don't have the money to have a trans repaired they were quoting me $4,300 to repair my trans. they were saying it was the pump that just didn't seem right , it was running great stopped at a red light ,then when i hit the gas nothing. it seemed to me it had to be something that was instant , i figured if it was electrical it would probably throw fault codes. after reading your post i knew it had to be something like this. I've worked on cars since i was a kid but automatic transmissions are way above my skillset .i started researching this issue watched allot of vids and finally pulled the pan just to have a look to see if i might be able to do it .never even seen the inside of a auto trans before . i went for it pulled the valve body and found the check ball had shot through the the plate . replaced all 8 in mine some of the older ones i guess its 7. when i looked at the TCM saw the pads were torn so replaced those pads and seals . reassembled all of it, said allot of prayers. now its fixed and working flawlessly. total out of pocket $152 saved $4,148 that i didn't have. i know you prob wont see this , but if you do thank you sir. btw i have a 17 express van 2500 with the 6L90 trans.