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Torque Converter or 4l80e toast?


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Bought this truck for CHEAP and was hoping to keep it that way but the inevitable is here lol

261 000 km

 

Started a few weeks ago with what i thought a frozen tranny (-37c), wouldnt budge after switching out of P.

After warming up for a few min i could rev it and it would hook up and off id go.

Well its slowly been getting worse and ita certainly not frozen. Now after switching to R or D i have to rev it to hook up and it seems to slip back out again if i lift off the gas....

 

Any tips other than a swap?

 

I was thinking of pulling a low mileage 4l80e and just swapping it ($130 ca or so).

Anything i should be keeping an eye out for when looking or is there a chance it can be brought back to life easily?

 

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Truck kept slipping and wouldnt engage in D or R untill warmed up and revved. Drove it about 10km lost 4th, another km lost 3rd then lost everything all together. It the sat for a few hours, R would catch but barely. Its now towed home awaiting some love.

 

I assumed the trans went but could it possibly be the torque converter?

Ive delt very little with them so dont know How to determine the issue between the two aside from the trans fluid being a terrible dark color and smelling a little burnt.

Any help would be appreciated!

Thanks in advance :)

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If you get a good code reader, you may be able to get a code from the TCM.  If the torque converter has failed, then it is pretty likely that there will be a code.  There might even be codes for what is wrong with the transmission itself.

 

You'll want a transmission that's from a 2000 or newer truck, with the same setup as your truck (either 2wd or 4wd), as to swap to the other output shaft, you have to completely disassemble the transmission (the output shaft is virtually the first part you install).

 

You can rebuild the transmission yourself, it's pretty straightforward.  I rebuilt mine when I installed 4wd in my truck.  New steels, friction discs, bushing kit, only one of the bands (didn't replace the reverse band, as it wasn't worn that much and you need a special tool to measure which pin you need to use with the new band), new pistons and a Transgo 4l80e-hd2 kit (alters shifting a bit and fixes some high-pressure problems).

 

I did manage to buy the GM tools for assembling the overdrive drum and the teflon sealing rings, and a thin plastic disc (these are cheap) for installing various lip seals correctly, and I downloaded some manuals on rebuilding 4l80e's.

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  • 3 months later...

I ended up finding a used remanufactured gm trans and torque converter for $500Ca, swapped it with some joys of not having a transmission jack but it does drive smoother than when i bought it!
Funny thing about that reman is the pan doesnt have a drain plug...
I'll be starting a tear down of the old 4l80e and rebuild myself in the garage in the next few weeks, it does look pretty straight forward.

If you get a good code reader, you may be able to get a code from the TCM.  If the torque converter has failed, then it is pretty likely that there will be a code.  There might even be codes for what is wrong with the transmission itself.
 
You'll want a transmission that's from a 2000 or newer truck, with the same setup as your truck (either 2wd or 4wd), as to swap to the other output shaft, you have to completely disassemble the transmission (the output shaft is virtually the first part you install).
 
You can rebuild the transmission yourself, it's pretty straightforward.  I rebuilt mine when I installed 4wd in my truck.  New steels, friction discs, bushing kit, only one of the bands (didn't replace the reverse band, as it wasn't worn that much and you need a special tool to measure which pin you need to use with the new band), new pistons and a Transgo 4l80e-hd2 kit (alters shifting a bit and fixes some high-pressure problems).
 
I did manage to buy the GM tools for assembling the overdrive drum and the teflon sealing rings, and a thin plastic disc (these are cheap) for installing various lip seals correctly, and I downloaded some manuals on rebuilding 4l80e's.
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newer 4l80e's didn't come with drain plugs (my '04 didn't, but older trucks did).  When I rebuilt mine, I welded a nut on the inside and bought a magnetic drain plug to screw in.  I did wind up using it right away, as I overfilled the transmission...

 

If you do this, you do need to be careful where you put it so it doesn't interfere with the valve body.

 

Rebuilding a 4l80e is pretty straightforward, but some tips/special tools come in handy (just off the top of my head, from doing this about 1.5 years ago):

 

-get the right kit for the transmission, it's based on the year the transmission was made.  Do not try to mix & match parts from other transmission, unless you are 200% sure they are the same part.  There have been multiple changes to internal parts to improve it's operation, and some either can't be backported (installed in older transmissions) or must be installed with several other parts.

-you may want to also install a shift kit when you do this.  I installed a transgo hd2 kit, it's supposed to have firmer shifts, and also fix some potential pressure problem area's in various parts of the oil pump and the valve body.

-a round plastic disc for installing lip seals.  It's specifically for doing this, and it's cheap

-transmission assembly lube, there are two types (thicker paste, and thinner stuff).  I just used the thicker stuff, if I was doing one again, I would get both types

-special tool for assembling the overdrive clutch.  This one is the most difficult to assemble, as it has 2 lip seals that have to go on simultaneously.  I have the right tool and it took me several tries to do it.  You might consider seeing if a local transmission shop will do it for a reasonable fee.

-there are also a bunch of tools for stretching & then shrinking some seals.  They make it easier to install the seals, but they can also be stretched by hand and shrunk with hose clamps.

-I made a mount for the transmission housing so I could mount it on an engine stand, I found it made it easier to disassemble, clean and install the various parts vs trying to do it on a work bench.

-I also made a simple puller for the pump housing, it goes in pretty tight and there's not much to grab/pry on to get it out...note, I did not try using gravity to get it out...

-I also made a spring compressor for assembling several of the clutch's. You might be able to do it by hand, or using clamps (I initially tried by hand, then tried some clamps before welding up a simple compressor to do it from scrap bits I had).

 

There's more info in my build thread here: http://www.dieselplace.com/forum/76-speciality-forums/125-drivetrain-2001-2010/871098-converting-04-sierra-3500-2wd-4wd.html#post8670242

 

Edited by davester
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