4L80E Transmission troubles, DTC 86

[Mogman]

Do the Tcm stand alone with the transmission? Or?

I do not understand your question, the TCM only controls the transmission

 

[Terra1936]

I have a non running 1123 and was going to pull trans and put in my 998 and wanted to use the Tcm and original harness. But I did not know if the harness needs engine feedback?

I do not understand your question, the TCM only controls the transmission

 

[Mogman]

I have a non running 1123 and was going to pull trans and put in my 998 and wanted to use the Tcm and original harness. But I did not know if the harness needs engine feedback?

Yes, it needs RPM and throttle position, would be very hard on a 6.2L not so bad on a 6.5L, IIRC all of them come with a crank sensor.

 

[LeafDriver]

Unfortunately I wasn't able to find any shops willing to take on this project as it seems all the big shops up here are fully booked for the next 6 months.
So instead of waiting around or having it sit in a parking lot for the next year or more I've decided to take on the challenge.
Will be going with a Monster 4l80e rebuild kit & stock torque converter as well as the Sonnax valve body upgrade.

Front and rear drive shafts are now out (Strangely it seems like some of the needle bearings were missing from one of the universal joints. unusual wear pattern on the inside may need to be replaced as well)
center support has been removed
Fluids drained
It seems I may be getting a bit of vampire disease as well, probably caught just in time. The fluid from the transfer case seems to be slighlty higher than it should be and seems contaminated.
Ready to start unplugging connections and unbolting the bell housing and converter when I get another good day.
Hopefully just burnt clutches and no shredded gears though I am anticipating some heat damage as well.

Boy oh boy here goes nothing.

 

[TNDRIVER]

Unfortunately I wasn't able to find any shops willing to take on this project as it seems all the big shops up here are fully booked for the next 6 months.
So instead of waiting around or having it sit in a parking lot for the next year or more I've decided to take on the challenge.
Will be going with a Monster 4l80e rebuild kit & stock torque converter as well as the Sonnax valve body upgrade.

Front and rear drive shafts are now out (Strangely it seems like some of the needle bearings were missing from one of the universal joints. unusual wear pattern on the inside may need to be replaced as well)
center support has been removed
Fluids drained
It seems I may be getting a bit of vampire disease as well, probably caught just in time. The fluid from the transfer case seems to be slighlty higher than it should be and seems contaminated.
Ready to start unplugging connections and unbolting the bell housing and converter when I get another good day.
Hopefully just burnt clutches and no shredded gears though I am anticipating some heat damage as well.

Boy oh boy here goes nothing.

You might want to look at wittrans.com......... I fear your problem may be in the valve body, if so its difficult for a novice to detect and correct. ATSG has a great repair manual worth the cost and the GM book can be found on the net. You might want to find a local "SPEED SHOP" as these have been the hot rodders goto trans in the past. They may know one of their own that would be willing to lend a hand. I have a limited amount of knowledge about the HMMWV's but a great deal more about 4l80's and I would not recommend a novice tackling one of these that is not working correctly. It's difficult to determine whats broke and whats not sometimes. Since you appear to have ATF all over your hands, GOOD LUCK and keep everyone posted! My 2 cents. And you might want to read some of monsters reviews.

 

[LeafDriver]

You might want to look at wittrans.com......... I fear your problem may be in the valve body, if so its difficult for a novice to detect and correct. ATSG has a great repair manual worth the cost and the GM book can be found on the net. You might want to find a local "SPEED SHOP" as these have been the hot rodders goto trans in the past. They may know one of their own that would be willing to lend a hand. I have a limited amount of knowledge about the HMMWV's but a great deal more about 4l80's and I would not recommend a novice tackling one of these that is not working correctly. It's difficult to determine whats broke and whats not sometimes. Since you appear to have ATF all over your hands, GOOD LUCK and keep everyone posted! My 2 cents. And you might want to read some of monsters reviews.

Thanks Ill add some more reading material to the pile.
amd good call on the review check. Wow!

 

[TOBASH]

Unfortunately I wasn't able to find any shops willing to take on this project as it seems all the big shops up here are fully booked for the next 6 months.
So instead of waiting around or having it sit in a parking lot for the next year or more I've decided to take on the challenge.
Will be going with a Monster 4l80e rebuild kit & stock torque converter as well as the Sonnax valve body upgrade.

Front and rear drive shafts are now out (Strangely it seems like some of the needle bearings were missing from one of the universal joints. unusual wear pattern on the inside may need to be replaced as well)
center support has been removed
Fluids drained
It seems I may be getting a bit of vampire disease as well, probably caught just in time. The fluid from the transfer case seems to be slighlty higher than it should be and seems contaminated.
Ready to start unplugging connections and unbolting the bell housing and converter when I get another good day.
Hopefully just burnt clutches and no shredded gears though I am anticipating some heat damage as well.

Boy oh boy here goes nothing.

Contact Eric H1 Hummer. He rebuilt his own and it is working well. He didn’t listen to me about the torque converter and needed to get the bell housing repaired. Other than that, he did a magnificent job and this transmission that was rebuilt is working flawlessly.

My tip (which he didn’t listen to and required subsequent extra attention), before you seat the torque converter, watch several YouTube videos on how to properly seat a torque converter prior to installation. You can really F things up if you do not properly seat the torque converter prior to installation. You will crack the bell housing and/or prematurely wear out the transmission.

You should hear three clicks/thumps/bumps as you spin the torque converter down into position. You then need to place a straight edge across the bell housing and measure down to the torque converter to ensure that it has recessed itself properly into position prior to installation.

If you don’t listen to me about the seating of the torque converter, you are gonna wind up spending a lot of money, and possibly need a brand new transmission.

 

[LeafDriver]

A day of good weather and I'm back at it. Took the whole day and a heap of effort but its down and out.

Note to others, do not try to remove the transmission and transfer case at the same time it's way too wobbly and pretty sketchy.
A lot of weight if you're only using an adapter plate for a floor jack.

Took just about all the daylight to get everything unplugged and out of the way.
Made sure to write down everything I was doing so I wouldn't be scratching my head over mystery bolts later.
Of course even with ramps set up there still wasn't enough space to just slide it out, lucky I had a couple bottle jacks and plastic stands on standby for that kind of thing.
Flex plate isn't cracked, no missing teeth too.
Input shaft looks okay, so far so good.
Next up is some cleanup and then I'll separate the Tcase from the Transmission end.
I was hoping to have everything back in before winter sets in but it seems like that's not going to be happening, so I'll take my time with it and aim for a spring re-installation.

 

[Retiredwarhorses]

A day of good weather and I'm back at it. Took the whole day and a heap of effort but its down and out.

Note to others, do not try to remove the transmission and transfer case at the same time it's way too wobbly and pretty sketchy.
A lot of weight if you're only using an adapter plate for a floor jack.

Took just about all the daylight to get everything unplugged and out of the way.
Made sure to write down everything I was doing so I wouldn't be scratching my head over mystery bolts later.
Of course even with ramps set up there still wasn't enough space to just slide it out, lucky I had a couple bottle jacks and plastic stands on standby for that kind of thing.
Flex plate isn't cracked, no missing teeth too.
Input shaft looks okay, so far so good.
Next up is some cleanup and then I'll separate the Tcase from the Transmission end.
I was hoping to have everything back in before winter sets in but it seems like that's not going to be happening, so I'll take my time with it and aim for a spring re-installation.

the job is a lot easier if you remove that exhaust crossover pipe, in fact, it needs to be off to remove and install The torque converter cover.

 

[TNDRIVER]

A day of good weather and I'm back at it. Took the whole day and a heap of effort but its down and out.

Note to others, do not try to remove the transmission and transfer case at the same time it's way too wobbly and pretty sketchy.
A lot of weight if you're only using an adapter plate for a floor jack.

Took just about all the daylight to get everything unplugged and out of the way.
Made sure to write down everything I was doing so I wouldn't be scratching my head over mystery bolts later.
Of course even with ramps set up there still wasn't enough space to just slide it out, lucky I had a couple bottle jacks and plastic stands on standby for that kind of thing.
Flex plate isn't cracked, no missing teeth too.
Input shaft looks okay, so far so good.
Next up is some cleanup and then I'll separate the Tcase from the Transmission end.
I was hoping to have everything back in before winter sets in but it seems like that's not going to be happening, so I'll take my time with it and aim for a spring re-installation.

Do I see blue paint behind the converter????? Are there any "tags" on the passenger side of the case? Should be two, one above "Hydramatic" and a yellow one further back. If that is paint inside the case I would guess that it is not the original transmission. My two cents.

 

[LeafDriver]

Do I see blue paint behind the converter????? Are there any "tags" on the passenger side of the case? Should be two, one above "Hydramatic" and a yellow one further back. If that is paint inside the case I would guess that it is not the original transmission. My two cents.

No tags on the transmission, and yes that is blue paint.

the job is a lot easier if you remove that exhaust crossover pipe, in fact, it needs to be off to remove and install The torque converter cover.

It did indeed have to be removed, there's not enough space to back the transmission and the transfer case off together when it is on.
However there was just enough space to wiggle the cover off if you turn it vertical towards the driver's side.

 

[TNDRIVER]

No tags on the transmission, and yes that is blue paint.


It did indeed have to be removed, there's not enough space to back the transmission and the transfer case off together when it is on.
However there was just enough space to wiggle the cover off if you turn it vertical towards the driver's side.

I'm going to go out on a limb here an opine this is not the original transmission that came in the truck. If so you have a pig in a poke, no telling what is wrong inside. My advice would be to procure a take out from a "HMMWV" not a civilian vehicle. The ones on the market on the civy side tend to have a ton of miles on them already. I think that is what you are looking at now. Price out a valve body, bushings, input shaft, clutches and converter and a swap would look pretty good. My two cents.

 

[LeafDriver]

I'm going to go out on a limb here an opine this is not the original transmission that came in the truck. If so you have a pig in a poke, no telling what is wrong inside. My advice would be to procure a take out from a "HMMWV" not a civilian vehicle. The ones on the market on the civy side tend to have a ton of miles on them already. I think that is what you are looking at now. Price out a valve body, bushings, input shaft, clutches and converter and a swap would look pretty good. My two cents.

Ah I see, still hoping that I dont have to buy an entire unit yet.
Though that was on the list as the last solution if a diy rebuild isn’t possible.

 

[LeafDriver]

I'm going to go out on a limb here an opine this is not the original transmission that came in the truck. If so you have a pig in a poke, no telling what is wrong inside. My advice would be to procure a take out from a "HMMWV" not a civilian vehicle. The ones on the market on the civy side tend to have a ton of miles on them already. I think that is what you are looking at now. Price out a valve body, bushings, input shaft, clutches and converter and a swap would look pretty good. My two cents.

Oh good news the tags are indeed there, they were caked in dirt so I couldn't see them.

View attachment Tcase.jpg
Separated the Tcase from the trans today, Tcase wasn't as heavy as I thought it would be.
Oops tore a gasket.

View attachment Tmission.jpg
When I try to spin the input shaft in neutral something inside is making a squeaking sound. Eyup not good.
I think I'll pull the valve body off soon and have a look at that.

 

[LeafDriver]

Sorry for the lack of updates, been a busy start to the year so this project has been put on the backburner for a while.

I decided to move the transmission inside as I didn't have enough space in the garage to really spread this thing out and I couldn't keep the environment clean enough.

So I finally got the valve body off, the leftover ATF is seemingly endless.



If you were betting on a valve body problem, congrats you get a cookie.



Before I removed it the gasket material at the edges was brittle and flaked off when I touched it.
As I removed it the material ripped and disintegrated, in some places it stuck to the transmission while the rest came off with the valve body as seen in the pictures.



Though I think this was caused by the torque converter going out rather than the direct cause of the problem.
I reckon from the events the timeline goes something like this:
- TCM/TCM harness goes bad
- Torque converter locks up at the wrong time and burns out the clutches
- This overheats the transmission
- Gasket cooks and disintegrates slightly
- gasket holds up for a while longer but eventually become completely unusable

I plan to take the old torque converter and the new one to a shop to have them both tested to see if that was one of the causes.

 

[LeafDriver]

Note: The Valve body surfaces are very sharp! Ouch.

Continuing with the disassembly, it seems I never purchased a set of 12 point sockets so I'll be doing the 4rth hub tomorrow.



clutches and steels were in decent condition, did not see any obvious damage aside from the friction material which has been worn away quite alot.



Bits of friction material ended up on the output shaft sleeve. This seems to be different from the clutch packs, maybe from the torque converter.




Not the greatest picture but I think the right side, the direct clutch hub got smoked. The interior surface is clean with no signs of heat damage or wear however. Maybe it is serviceable? There are also no grooves cut into the surface from slipping clutches/steels.



I havent disassembled them fully yet but here's a bonus picture of the extreme duty sonnax direct clutch which will be installed into the center of this assembly later.

Also all the planetaries spin easily with just the residual ATF coating them, of course I'll have to go through each assembly thoroughly just to clean and inspect them.

 

[TNDRIVER]

Note: The Valve body surfaces are very sharp! Ouch.

Continuing with the disassembly, it seems I never purchased a set of 12 point sockets so I'll be doing the 4rth hub tomorrow.

View attachment 963404

clutches and steels were in decent condition, did not see any obvious damage aside from the friction material which has been worn away quite alot.

View attachment 963405

Bits of friction material ended up on the output shaft sleeve. This seems to be different from the clutch packs, maybe from the torque converter.


View attachment 963406

Not the greatest picture but I think the right side, the direct clutch hub got smoked. The interior surface is clean with no signs of heat damage or wear however. Maybe it is serviceable? There are also no grooves cut into the surface from slipping clutches/steels.

View attachment 963407

I havent disassembled them fully yet but here's a bonus picture of the extreme duty sonnax direct clutch which will be installed into the center of this assembly later.

Also all the planetaries spin easily with just the residual ATF coating them, of course I'll have to go through each assembly thoroughly just to clean and inspect them.

Seeing you are new to this YOU TUBE can be your friend . There are two or three GOOD videos on these to view. How many planetary gears in your reaction carrier and output carrier? AND, this is not the first time this trans has been apart. Good Luck

 

[TNDRIVER]

Note: The Valve body surfaces are very sharp! Ouch.

Continuing with the disassembly, it seems I never purchased a set of 12 point sockets so I'll be doing the 4rth hub tomorrow.

View attachment 963404

clutches and steels were in decent condition, did not see any obvious damage aside from the friction material which has been worn away quite alot.

View attachment 963405

Bits of friction material ended up on the output shaft sleeve. This seems to be different from the clutch packs, maybe from the torque converter.


View attachment 963406

Not the greatest picture but I think the right side, the direct clutch hub got smoked. The interior surface is clean with no signs of heat damage or wear however. Maybe it is serviceable? There are also no grooves cut into the surface from slipping clutches/steels.

View attachment 963407

I havent disassembled them fully yet but here's a bonus picture of the extreme duty sonnax direct clutch which will be installed into the center of this assembly later.

Also all the planetaries spin easily with just the residual ATF coating them, of course I'll have to go through each assembly thoroughly just to clean and inspect them.

Found floating around......ATRA-4L80E-Rebuild (GM).... just saying!

 

[LeafDriver]

Found floating around......ATRA-4L80E-Rebuild (GM).... just saying!

Thanks! That's a great resource to add.

I have been using:

- Technical manual stuff https://www.hummerpartsguy.com/TRANSMISSION-4L80E_c_2823.html

- The ATSG 4l80e manual and the GM 4L Transmissions: How to Rebuild and Modify books


My 4rth planetary carrier has 4 satellites, helical gears. I'm guessing the rear output planetary will be the same.
I have heard that the original humvee 4l80e's should have straight cut gears.


Overall this one was in great shape.
I flipped the planetary upside down and all the satellite gears and their needle roller bearings fell out. Curses...
Then spent 2 hours trying to find a single missing needle bearing and finally found it stuck to my magnetic lamp.

I also decided to open the 4rth gear clutch hub to get at the piston seals which were showing signs of tearing at the edges. The sealing surfaces were clean with no scratches or debris inside.
Of course it turns out I need to order a special tool to reassemble that piston without damaging the seals but I'm glad I did it anyways.

I think the most time consuming part of this project will be cleaning everything.

 

[TNDRIVER]

Thanks! That's a great resource to add.

I have been using:

- Technical manual stuff https://www.hummerpartsguy.com/TRANSMISSION-4L80E_c_2823.html

- The ATSG 4l80e manual and the GM 4L Transmissions: How to Rebuild and Modify books


My 4rth planetary carrier has 4 satellites, helical gears. I'm guessing the rear output planetary will be the same.
I have heard that the original humvee 4l80e's should have straight cut gears.

View attachment 963450
Overall this one was in great shape.
I flipped the planetary upside down and all the satellite gears and their needle roller bearings fell out. Curses...
Then spent 2 hours trying to find a single missing needle bearing and finally found it stuck to my magnetic lamp.

I also decided to open the 4rth gear clutch hub to get at the piston seals which were showing signs of tearing at the edges. The sealing surfaces were clean with no scratches or debris inside.
Of course it turns out I need to order a special tool to reassemble that piston without damaging the seals but I'm glad I did it anyways.

I think the most time consuming part of this project will be cleaning everything.

I don't ever remember the needle bearings "falling" out....... seen straight sun and planets in a couple of motor home transmissions..........the heavy duty trans have 5 gears in the planetary. I would investigate the needle bearing issue a little further. They can be rebuilt if no one has tig welded the centers in place.