# 4L80E Rebuild costs?



## ontario026

So who has had a 4L80E rebuilt, what was the total cost for re/re the tranny and rebuilding it??

My truck started occasionally setting a P1870 code for trans slipping component... Went to the local reputable transmission shop yesterday and we went for a road test with his scanner hooked up, and the slip rate is getting a little high... apparently there is part of the valve body that controls the torque converter lockup, and it wears allowing more slip? one fix would be to drop the valve body out, and install a new valve in the valve body that has some kind of teflon seal to help increase torque converter lockup pressures ... The owner of the shop considers this a band-aid fix for a tranny with 140K miles on it.. Cost of probably around $600.... 

His recommendation is to run it till it dies (or until a more conveniant time, like spring/summer since I have no backup truck) and do a full rebuild, and he estimates that provided I run with the tow/haul mode, and avoid overdrive that I should be able to finish this winter without problem. While driving the truck I feel no slippage, and the only time it sets the 1870 code is when I hog it down the highway at 75mph+.... he estimates total cost of full rebuild approx $2200 

Hmmm so what to do?? I think I will lean towards the full rebuild, hopefully next summer or so, and take it easy on the ole girl for now....

Any input?
Matthew


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## CityGuy

Just my opinion but for 2200 get a rebult from dealer for an additonal 800 or so. I did and now have a 3 year/100,000 on it. JMO


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## Nasty-Z

$2200 might be a shade high but nevertheless a good price , convertors alone for the 4L80E are pricey for good units, avoid bargain basement convertors/rebuilds on transmissions like the plague .

Does the rebuilder offer a warranty ?

TOM


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## 2COR517

I paid just under 2 grand a year ago. Local shop, fantastic reputation. 12mo/12k warranty. 

The general consensus is that the GM remans are crap. Assembled in Mexico by guys that don't have to look you in the eye when something goes wrong after taking half your summer vacation money. For me it will be only a local rebuild or Jasper. Or better yet, some guy in PA.....


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## sweetk30

is that canda or us money prices ? 

and fyi to all who drive a auto overdrive vehicle. 

dont drive or load work it in od position. always use 3rd gear. 

this gets you full pressure from the internals. make the tranny work in its strongest state. 

then when in o/d you get grandpa smoth shifts / less fluid pressures / and o/d only has 1-2 clutches in the pack on most trannys not like the main packs with up to 6 clutches. 

hope this helps. and if you are mech inclined get a crate tranny and swap it your self. real easy to do. save the cash.


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## 2COR517

My price was US dollars. If the 2200 is CDN, that's a very good price.


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## GMC Driver

Should be able to do it around $2000. There's a shop out here that does a great job, Gary's Transmission. I've had him do a couple about 5 years back - reverse band out of them.

I'll see how much the pricing has changed - the oldest one is pretty sloppy in second.


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## Evanbrendel

have one built and beefed up espicaly since its a plow truck


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## ontario026

yes, the prices I was quoting are in canadian funds.... The tranny shop is by far the best in our area, never heard anything bad about them. I have known the owner through my father since I was quite young (he was on the same volunteer fire dept as my dad when I was a kid) I forgot to ask what warranty they put on them, but I would assume at least a year. They are basically the only shop around that plow guys and performance guys take their stuff...

SweetK30, the tranny shop owner was explaining to me about that same point, work the tranny in 3rd not OD, due to something about clutches locking out the OD planetary gear set or something like that... (inner workings of an auto tranny is all greek to me) I had always done R-OD shifts, assuming that there was no difference between that and a R-3 shift, since i didn't ever normally get out of 1st gear, but apparently there is a difference... Just hard to get used to a R-3 shift... R-od is easier,,,,

Matthew


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## mkwl

Did your check engine light come on when it threw the code? Just wondering...


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## ontario026

No it didn't, the P1870 code is one that has to get triggered during 2 drive cycles before it will set the engine light (so I have been told) as long as it doesn't set the engine light, the key off will clear the code... 

once the computer sets the 1870 because of it sensing too high of a slip rate, it will go into a fail safe mode where it maxes out line pressure resulting in very hard shifts, that is the only way I can tell that there is a code lingering then I can see it if I use my scanner to read the computer.. then I can either erase it, or just wait for the key off to erase it. Mine is not slipping bad enough yet I guess to set the engine light,,,,

Matthew


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## Detroitdan

IIRC the 4l80e is different from the 700r4 and other OD trannies in that 4th is a gear, not OD. In fact OD can engage in 3rd and 4th, on top of each gear. You can also lose OD function and still drive it indefinitely, because it isn't the transmission that is slipping, it is simply a hydraulic actuator not engaging OD. So, there is no harm in plowing in 4th gear, because you are very unlikely to engage OD, it only comes on when you get to about 42 mph. And as far as towing, if the load is too great, it will not hold in OD so you can't hurt anything. What K30 is talking about is the correct information for a 700r4, though. If people only knew to put them in 3rd when towing or plowing, a few million of those trannies wouldn't have died prematurely. I remember the bad rep they got back in the 80s, when in reality if used properly they were a really good tranny. My 83 even said in the owners manual you could leave it in OD for towing.
What you said about the valve body sounds like what happened to mine. After a few miles when the tranny was up to temp, it would slip back out of OD into 4th. This happened because the wear in the actuator sleeve would allow fluid to bleed by once it was hot and thinned out enough, losing that line pressure engaging OD. Took it to a very reputable tranny shop who told me 4th gear was "blown" and I needed a rebuild ($2200) or a new one ($3000). I tried to argue with them, saying that if something mechanical were broken, it would fail all the time, not some of the time. I didn't believe them, so I did a ton of research online and learned what the problem was. First went through and replaced TCC lockup solenoids then shift solenoids, then as a last resort I pulled the valvebody down and did the Sonnax Surecure. This involved removing the actuator valve, reaming it out with the special tool, then resleeving it and installing the new actuator. Wasn't very difficult at all, and including all the solenoids and fluid I bought in addition to the Sonnax kit, I think I spent about $400. It has worked flawlessly for 2 years now, plowing and towing heavy. If you want any more information about this let me know.


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## B&B

Matt if you're a proactive type of guy have the rebuild the valve body now and save the "complete" rebuild for when it actually needs it or you have the time for it as there's likely nothing wrong with the trans itself. There's many things that can cause the 1870 code but few of them have to do with the mechanicals in the trans, more like a control issue in the valve body from worn spool valve bores. For guys that aren't aware late model transmissions use aluminum valve bodies and most use steel spool valves in those valve body's. Like anything else the steel valves stroking in an aluminum bore tend to wear the bore to the point that you begin to have leakage around the spools and thus you end up with misdirected and lowered fluid supplies and pressures to the components. And on the 4L80E's its the converter supply and control valves that wear the most (hence there's aftermarket kits to repair them). The only other real cause for converter slippage is the clutch linking being worn in the converter itself, but as long as you don;t work the converter hard as it's trying to hold you'll add no additional wear to it so it should last until you're ready to rebuild the entire trans. Or if you do the valve body rebuild now it make restore converter function back to nearly 100%. Some of this does depend on how well the trans was maintained and how hard it's been worked in those first 140K but 200K isn't out of line for a properly maintained 80E. Regular fluid changes and keeping fluid temp at bay are more important than how hard it was run as far as the converter and clutch pack lifespan goes, it's not too dependent on actual use/abuse in a stock 6.0 truck. 

First thing, to reducing converter clutch usage (apply and release functions) is to run the truck correctly. These transmissions will engage the converter in both 3rd and 4th gear so there isn't too much you can do there in daily driving conditions except only use OD if you're actually running a high enough road speed to keep the RPM's up when it's in OD. Because lugging along in OD at low speeds with the converter locked places much more strain on the clutch and thus increase the strain and chance of slippage. No different then running around in too high a gear on a manual trans. Just doing this (on any truck) prolongs the life of the converter alone.

Second, using tow/haul can actually put more wear on the converter from continuously engaging and releasing when plowing depending on you're accounts. Because these transmissions engage the converter as soon as the trans shifts to second gear when in T/H. If you have short plow runs where the trans shifts to second, you go just a short distance further and have to then stop/slow down the converter will be engaging and disengaging on every pass you make. This directly contributes to converter wear and will cause the trans fluid temps to run higher due to the extra friction during this constant engage/release process. Guys don't realize this little detail and think that using T/H for all plowing conditions is the favorable way to help the trans, and this is more incorrect then they even know.

You're far better off to run in non T/H and if you need it to hold 1st gear just a bit longer to reach the end of the run, hold the trans in first manually yourself, don't rely on T/H to do it for you. Or, if you do require 2nd gear for longer runs simply start in manual 1st and upshift it to 2nd manually. Running in non T/H and shifting it manually the converter won't be briefly engaging/disengaging every time it's goes to 2nd gear.


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## B&B

Detroitdan;949553 said:


> IIRC the 4l80e is different from the 700r4 and other OD trannies in that 4th is a gear, not OD. In fact OD can engage in 3rd and 4th, on top of each gear.


This is incorrect Dan. 3rd is direct and 4th is an actual overdriven gear (.75 overdriven to be exact) with its own overdrive clutch pack, overrun clutch, over drive roller clutch and overdrive planet carrier assembly. Now they do use both the direct clutch and the overdrive clutch to produce the overdrive gear ratio but without the overdrive specific components there would be no overdrive ratio and that is what separates them from the Turbo 400's of yesterday. In fact a 4L80E is basically an electronically controlled Turbo 400 with the extra components to have an overdrive gear.

In fact they are so similar many of the internal hard parts will DIRECTLY interchange between the two. Guys use the 5 pinion gear planet carriers from the 4L80E's in the old Turbo 400's as an effort to increase their durability. And as you're probably aware the 400's were the benchmark of durability for over 30 years.

They really are that similar.


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## Detroitdan

B&B;949605 said:


> This is incorrect Dan. 3rd is direct and 4th is an actual overdriven gear (.75 overdriven to be exact) with its own overdrive clutch pack, overrun clutch, over drive roller clutch and overdrive planet carrier assembly. Now they do use both the direct clutch and the overdrive clutch to produce the overdrive gear ratio but without the overdrive specific components there would be no overdrive ratio and that is what separates them from the Turbo 400's of yesterday. In fact a 4L80E is basically an electronically controlled Turbo 400 with the extra components to have an overdrive gear.
> 
> In fact they are so similar many of the internal hard parts will DIRECTLY interchange between the two. Guys use the 5 pinion gear planet carriers from the 4L80E's in the old Turbo 400's as an effort to increase their durability. And as you're probably aware the 400's were the benchmark of durability for over 30 years.
> 
> They really are that similar.


Maybe my terminology is incorrect, but you said yourself in the other post that TC will engage in 3rd or 4th. I guess this is what I meant. My understanding, and how it's been described to me by transmission experts, suggests that 3rd or 4th can be used either in lockup or out, hence my statement. If what you're saying is 4th is OD only, but it can be used in lockup or out of lockup, then perhaps thats where the discrepency is. What I was calling 4th is what your calling OD, and what I called OD is what you call torque converter lockup. Anyway, I guess it's all the same. 
And I did know the 4l80e is based on a th400. 
Not sure what year OP is talking about, but you refer to tow/haul mode which came out long after my truck was made. I don't have that option. It is possible to retrofit the older 4l80s to a manual lockup, but it's easier on the earlier (than mine) models. Never saw a need for it. If I'm pulling a big hill loaded the trans downshifts when it needs to, and when the speeds get low enough it comes out of lockup.
Like I said before, if my truck doesn't go to lockup or OD until 42 mph, then I don't see any reason to manually shift it into 3rd or 2nd. Since I'm starting out in first, and occasionally see second, then the 3rd and 4th overdriven gears are not a factor.

Don't take me the wrong way, I'm not trying to argue, I'm just trying to explain how I understand it to be.


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## Detroitdan

so let me rephrase my original statement. You can lose torque converter lockup and still have "4th" gear. I drove mine for quite awhile that way before I got it straightened out. It only boils down to about a 200 rpm difference.


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## 2COR517

ontario026;949483 said:


> No it didn't, the P1870 code is one that has to get triggered during 2 drive cycles before it will set the engine light (so I have been told) as long as it doesn't set the engine light, the key off will clear the code...
> 
> once the computer sets the 1870 because of it sensing too high of a slip rate, it will go into a fail safe mode where it maxes out line pressure resulting in very hard shifts, that is the only way I can tell that there is a code lingering then I can see it if I use my scanner to read the computer.. then I can either erase it, or just wait for the key off to erase it. Mine is not slipping bad enough yet I guess to set the engine light,,,,
> 
> Matthew


What you really want to do is [R] to [1] to [R] shifting. Once you get used to it, it's not big deal. Saves a tremendous amount of wear on your reverse band, which as we all know is the weak link of the 4L80e.

I learned this the hard way, to the tune of 2 grand. My trans had alot of life left in it too.
http://www.plowsite.com/showthread.php?t=74317&highlight=4L80e


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## B&B

The problem with your terminology is that you're confusing 4th/OD with TCC (torque converter clutch) engagement. They are two completely different things and completely different components as well as their functions, and the TCC does not provide an overdrive.

You can call 4th "OD" if you'd like as thats exactly what it it is, an overdriven gear of .75. And 3rd is direct (1:1), 2nd is 1.48 underdriven, and 1st is 2.48 under driven. So 4th or OD it's still overdriven gear. 

However 4th/OD has absolutely nothing to do with TCC functions and operates totally independently from the TCC, whether it's applied or released. And the TCC provides no additional overdrive. It simply reduces engine RPM's because once it engages there's no slippage between the engine and the trans (as there is continuously with a non lockup converter or when a lockable converter is of course locked), hence you see an RPM reduction due to the elimination of converter slippage, which all converters have unless they're of a lockup design (as most have been for 20 years now) and it's locked up. And this is where the additional RPM reduction comes from. And from the original standpoint a lockable TCC was only invented as a means to increase MPG's and reduce trans heat. It wasn't designed for any other purpose expect efficiency.

And yes you can totally disable the TCC and you'll still have OD (.75) when in 4th gear range, as like I said one has nothing to do with the other. Same way with lockup in 3rd, you can and do have it but it isn't providing an overdrive. 3rd is direct and even when you lock the TCC it's still 3rd, which again is direct 1:1..no overdrive at the output shaft what so ever.


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## RichG53

Does most of this info hold true for the 4L60E ??? Or are there different steps to follow ??

Which is better 4L80E or 4L60E ??? And why???
In other post It was stated to use Tow/Haul mode for plowing ....Is that only good to do for long runs or Drives too ????

Now it seems it should not be used...Getting CONFUSED !!!!


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## B&B

Yes it applies to the 60E's also for the most part. The functions are done the same although some components used to do so are different. But other than that, all the fundamentals all apply.

The 80E's are superior to the 60E's in virtually every aspect. Strength, holding capacity, and durability. A 60E is like the newer fully electronic version of the old 700R4 in much the same way I mentioned that the 80E's are the newer electronic version of the venerable Turbo 400's. 

T/H or no T/H is a case by case answer based on what you're doing. Very short runs where you'd like it to hold in 1st gear but you don't want to hold in manually then T/H will accomplish that, as long as the speed stays low enough for it to actually hold it in 1st. However if you're making runs where you need an upshift to 2nd but only for a short distance, or speeds are too great to stay in first then non T/H is better as you'll get no brief converter engagement once it shift to 2nd. Thus reducing wear on the converter. In simpler words, if you're using 2nd but only briefly; then no T/H is wanted. But if you pushing long distance in 2nd or even 3rd then T/H is a good idea.

On road while traveling between accounts at normal road speeds T/H is almost always a good idea for several reasons. First, it will increase RPM's in any given gear and hold that gear longer, thus increasing trans fluid flow through the cooler, increases cooling fan speed to draw additional air across the trans cooler and radiator (important when the plow is blocking airflow) and also engage the TCC in all gears above 1st thus reducing heat production generated from the converter in the first place. And second, the extra RPM's also keep the alternator charging at a higher rate to help restore battery charge voltage.

In an older truck that isn't equipped with T/H; holding a lower gear then you would normally run is a good idea for the same reasons. Of course road conditions will dictate that and is the reason I stated it's done on a case by case basis and it's up to the operator to know what is warranted and when. 

The trick is to educate the operator as to what they should be doing and why.


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## mkwl

B&B;949604 said:


> Matt if you're a proactive type of guy have the rebuild the valve body now and save the "complete" rebuild for when it actually needs it or you have the time for it as there's likely nothing wrong with the trans itself. There's many things that can cause the 1870 code but few of them have to do with the mechanicals in the trans, more like a control issue in the valve body from worn spool valve bores. For guys that aren't aware late model transmissions use aluminum valve bodies and most use steel spool valves in those valve body's. Like anything else the steel valves stroking in an aluminum bore tend to wear the bore to the point that you begin to have leakage around the spools and thus you end up with misdirected and lowered fluid supplies and pressures to the components. And on the 4L80E's its the converter supply and control valves that wear the most (hence there's aftermarket kits to repair them). The only other real cause for converter slippage is the clutch linking being worn in the converter itself, but as long as you don;t work the converter hard as it's trying to hold you'll add no additional wear to it so it should last until you're ready to rebuild the entire trans. Or if you do the valve body rebuild now it make restore converter function back to nearly 100%. Some of this does depend on how well the trans was maintained and how hard it's been worked in those first 140K but 200K isn't out of line for a properly maintained 80E. Regular fluid changes and keeping fluid temp at bay are more important than how hard it was run as far as the converter and clutch pack lifespan goes, it's not too dependent on actual use/abuse in a stock 6.0 truck.
> 
> First thing, to reducing converter clutch usage (apply and release functions) is to run the truck correctly. These transmissions will engage the converter in both 3rd and 4th gear so there isn't too much you can do there in daily driving conditions except only use OD if you're actually running a high enough road speed to keep the RPM's up when it's in OD. Because lugging along in OD at low speeds with the converter locked places much more strain on the clutch and thus increase the strain and chance of slippage. No different then running around in too high a gear on a manual trans. Just doing this (on any truck) prolongs the life of the converter alone.
> 
> Second, using tow/haul can actually put more wear on the converter from continuously engaging and releasing when plowing depending on you're accounts. Because these transmissions engage the converter as soon as the trans shifts to second gear when in T/H. If you have short plow runs where the trans shifts to second, you go just a short distance further and have to then stop/slow down the converter will be engaging and disengaging on every pass you make. This directly contributes to converter wear and will cause the trans fluid temps to run higher due to the extra friction during this constant engage/release process. Guys don't realize this little detail and think that using T/H for all plowing conditions is the favorable way to help the trans, and this is more incorrect then they even know.
> 
> You're far better off to run in non T/H and if you need it to hold 1st gear just a bit longer to reach the end of the run, hold the trans in first manually yourself, don't rely on T/H to do it for you. Or, if you do require 2nd gear for longer runs simply start in manual 1st and upshift it to 2nd manually. Running in non T/H and shifting it manually the converter won't be briefly engaging/disengaging every time it's goes to 2nd gear.


So, even for driving from house to house, it's better not to use T/H? Or is that just while actually plowing?


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## B&B

Both if it's all short distances. Short travel distances (say for example block to block with a stop in between) T/H isn't wanted or if you drives/lot are short. 

If your distances are a few miles between and at a relativity sustained speed then T/H is warranted.


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## RichG53

Well !!! Thank you very much !!! That helped out a lot ...


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## GimmeSnow!!

Bringing back an old thread because I've got two trucks in getting trans rebuilds right now. I'm a little confused. I never turn overdrive off or tow haul on unless I'm pulling a trailer. So should I have the tow haul on when I'm everyday driving or on the expressway if I have a v-plow and 2yd salt spreader? I also didn't know there was a difference between TH and overdrive off. My older dodges have an overdrive off button, my newer GMC's have a TH button. When should I be using TH and when should I be turning overdrive off?


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## sweetk30

simple if no o/d off button put shifter in next lowest gear other than top gear / overdrive.

gm trannys like these shift diffrent in 3rd over the 4th / o/d position as the computer knows its getting worked hard and bumps line pressures up and shift points diffrent.

tow haul is nice and does kind of the same thing. but if not going over 40-45 mph and or working keep it in non overdrive is what i do.

and if the tranny cycles in/out in/out in/out all the time it will die much faster. and keep the engine rpm's in the power band to work better as a unit in prime power band.

and to keep any auto tranny happy read some of this i put together. http://www.plowsite.com/showpost.php?p=1347746&postcount=2


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