# 4L80E, No Overdrive



## SubUrbanMonster

So I've found a few posts here, and I have a detailed Idea of whats causing my no overdrive problem. So far, I've determined that its not a major internal hard part failure. In OD, truck shifts smooth through First, second and third, just wont shift to overdrive. Fluid is clean, no metal shavings, no burnt appearance or smell. To be quite honest, the trans looks great inside the pan. The trans shop guy said the transmission was rebuild a few years ago, which is good, trucks got 208k on her. However, hes trying to tell me the trans needs a full rebuild, but he also tells me losing overdrive has nothing to do with the TCC solenoid period, he swears its a hard part, but. I'm not about to spend 2200 on something i shouldnt need, especially since I dont have that money to spend right now. Trans shifts great, no hard shifts, no delays, no slipping, and no codes popping up. Just wont shift into 4th gear. I've cleaned the plug on side of trans, I've flushed trans, no change. Im looking to order some normal parts for me to install so I can get my over drive back, and hopefully get my trans to last me until I can afford to get my new one, happy birthday me  

so far, I'm ordering a TCC Solenoid, and im looking to order a rebuild kit for the valve body, as Im told when I lose overdrive its due to the AFL valve (the valve that controls lockup). Id like to also install all new shift solenoids since I'll be down there anyways, looking into a stage 2 shift kit, but im told it can lower the life expectantcy on the trans, and since i got the truck on a lien sale and dont know the history, id wrather be safe than sorry and keep it running and driving well until I can afford the transmission/transfercase replacement at the end of summer. 

Or is it possible that my problem is caused by something else? I've already been through several eliminating procedures. I'm looking into these parts from Sonnax:

TCC Regulator Valve Kit
Part Number: 34994-01K
or:
Part Number: 34994-18K

The difference is 18K comes with a valve sleeve and retaining pin

Id like to purchase these part number add ons to the Regulator Valve Kit:

Part Number: 34994-TL18, comes with Reamer, Reamer Jig, and guide pin.

All i'm trying to do is get my overdrive back and continue my daily driving. 
Any adivce guys?


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## Detroitdan

Does it ever work? When mine was going bad, it worked fine in the morning until the trans got up to temp, then it started slipping. Exact same place everyday it would slip out of OD. It was a matter of the fluid getting warm and thin enough to leak past the AFL valve. If yours never works it could be something else, or it's just leaking so bad the thicker cold fluid is passing by it too. Maybe if you have been driving it a long time like that.
Don't put in a shift kit, the Sonnax kit comes with instructions to "firm up" the shifts by boring a certain hole. You peen it down and redrill it smaller, pretty easy actually. Mine hits the 1-2 shift pretty darn hard. Almost scary hard, depending on what rpm you hit it at. I have a B&M Shiftplus electronic adjustable shift kit too, which worked well but after modifying the shift in the tranny I keep the Shiftplus turned off. 
. Message sent.


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## Detroitdan

Also, I've heard shift kits extend tranny life. The faster the shift occurs, the less time for heat to be created.

What exactly do you have for a vehicle? I'm not sure you've got a 4l80e, most Subs had 4l60e. If it's a diesel you might, but just make certain what it is before you order anything.


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## SubUrbanMonster

I deff have a 4L80E. Its a 93 Suburban 4x4 8 lug 2500. Shes got a small block in it, but its a GVWR of 8600, and I dont see them puttin no 700R4 in that big of a truck, havent heard of that since 6.2 diesel suburbans in the 80's. I know they put 4L60E's in half ton suburbans. According to my research, the look of the trans, and the shops ive taken it to, its a 4L80E, unless of course these trans shops are as shifty as they look.


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## SubUrbanMonster

Also, It just plain doesnt work. It doesnt engage periord. Otherwise, not a single issue at all. I was first told to just order a TCC Solenoid and replace it, clean the trans plug, and thatll be the solution.


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## Sydenstricker Landscaping

It is for sure an 80E. GM started using the 80E in 91 on the 3/4 and one ton trucks. Before that was the good ole TH400. 93 was the first year for the 4L60E. Sounds very doubtful that it is a major internal hard part. Could be a screwey solenoid or that afl valve.


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## Detroitdan

SubUrbanMonster;1036126 said:


> Also, It just plain doesnt work. It doesnt engage periord. Otherwise, not a single issue at all. I was first told to just order a TCC Solenoid and replace it, clean the trans plug, and thatll be the solution.


Have you done that yet? What have you actually done so far? There are several things I tried before getting to the surecure, first was tcc solenoid, then shift solenoids, then trans temp sender, o-ring for trans electrical plug, etc.
Mine worked thru all the gears, but in OD the tcc would disengage after a couple miles. I could still drive it in OD, I didn't have to shift into 3rd (D). I just had a slight increase in rpm. Can you drive in OD still?


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## SubUrbanMonster

In overdrive It drives great, as if theres no problem what-so-ever. Shifts smooth and right on time all the way through gears, but overdrive doesnt engage. At 60, I'm pullin close to 2500RPM's. I just bought the truck recently. Needs work, on a side note, I got the front wheels off her last night to do upper ball joints, and i come to find out I have no caliper bolts, my calipers were just hangin around on the rotar. The genius that had this truck prior amazes me more and more every day.

So far, I've cleaned the plug, and changed fluid and filter, and have had several idiot trans guys dick me around. Id love to get these parts ordered ASAP, hopefully today, so guys please tell me what you think. I'm taking it to a friends shop and hopefully his trans guy will know a little more.


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## SubUrbanMonster

so its been a little, been workin alot of overtime and im just now starting to continue working on the pile. update time. i took it to my buddies trans guy, he ran a diagnostic on it, but the computer was reading my trans as a 4L60e, but my trans is CLEARLY a 4L80e. gm dealer ran the code on my ecm and it doesnt match my vin. dealer said a new one would run me 240, which is WAY less than i expected. now, im still way behind in bills, so before i go to throw 250 on a new one, i located one at pick-a-part, and half price weekend starts this friday. i hid the ecm i found (its off a 1991 2 wheel drive, 8 lug 350 tbi with a 4L80e) and with half price day, its only 28 bucks, so this friday ill be there at opening gona pick it up throw it in and test drive her after she warms up, and if i get my overdrive back and she runs and drives fine i will deffinately have justified the missed overtime and the 40 minute drive. if not, well the ecm brand news only 240, so ill get the matching vin ecm for the suburban.


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## SubUrbanMonster

side note, idiot ase (ass) certified friend attempted to fix by running jump wire from vw bug battery straight to trans fuse after discovering now power to pin e on trans harness plug. send my trans into limp mode, stayed in limp until ecm was reset. after that, i attempted to trouble shoot further, installed a ECT sensor and ignition switch, which got me know where EXCEPT now in 2nd and 3rd on the shift collum, truck acts like its in 2nd for both, and overdrive gives me all 3 gears, which is no change at all from the original problem. still not throwing any codes. shift linkage? something in collum from dropping down for the ignition switch? ignition switch no correctly installed maybe? any advice would be GREATLY appreciated guys. THANKS!


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## cool78259

*4l80e no od fix*

the tps throttle positioning sensor will keep your transmission from switching to od. i have a 93 chevy 6.5td with a 4l80e.. I also have a fix that will bypass the tps and allow your truck to go into od until repairs can be made.


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## cool78259

*4l80e no od*

the transmission control module has to see a signal voltage from the tps between .04 and .05 volts. to allow the transmission to change to od. the tps costs about 160.00 at most autoparts. i had the same problem i changed the tcm w/cpu rebuilt my tranny had frequent transmission fluid changes. but after extensive troubleshooting. it was the tps. when i would drive it, on 1st take off the trans would work great, but then it would bog down and i could not get it to go past 50 mph.. let it cool down and it would work again. it was like a broken record. the tps was getting hot and losing its reference signal to the tcm and falling out of od.


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## cool78259

look at my post it will solve your problem


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## cool78259

the location of the tps, attached to the left of the injector pump on a 6.5 turbo diesel c3500.


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## BigLou80

Detroitdan;1036122 said:


> Also, I've heard shift kits extend tranny life. The faster the shift occurs, the less time for heat to be created.


Why does this myth persist ? shifting has no tangible effect on heat creation.


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## MI Green

I am going to resurect this old post. I have a 93 6.5 and I was losing 4th and torque lockup at 175 trans temp and all I had to do is flick the igition on and off and it would come back till 180 then I could not get it back. Now it won't go I to either at any temp. Ive only had this truck a week and it was an issue with the last guy. Anyone have more ideas?


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## cool78259

I have a 93 one ton chevy with a 4l80e , my truck would not go into third gear or overdrive. I bought a transmission Manuel on the 4l80e . Make a long story short I drained transmission fluid, pulled cover and replaced solinoid B controls third,4th and overdrive. Once I did that now it shifts like a new truck. It's no rocket science with the directions. Good luck!


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## MI Green

cool78259;1654822 said:


> I have a 93 one ton chevy with a 4l80e , my truck would not go into third gear or overdrive. I bought a transmission Manuel on the 4l80e . Make a long story short I drained transmission fluid, pulled cover and replaced solinoid B controls third,4th and overdrive. Once I did that now it shifts like a new truck. It's no rocket science with the directions. Good luck!


Is that considered the 2-3 when you buy it?


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## Blizzard1980

Im no pro at it but i've heard guys talking about ignition switches go bad and therefore issues with tranny shifting on 4l80e-s.


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## MI Green

Blizzard1980;1654910 said:


> Im no pro at it but i've heard guys talking about ignition switches go bad and therefore issues with tranny shifting on 4l80e-s.


Ya I've read about 6 causes that could make my symptoms


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## MI Green

I tell you what I hate talking to mechanics. They just push a rebuild........ Just got off the phone with a friend who owns a high quality repair shop and he said I needed a new torque converter. Well to get up to speed look at http://www.lawnsite.com/showthread.php?t=414254. This truck has been turned up and once I locked in at 55 I can pull 85mph in torque lockup floored and this truck pulls 15psi of boost and it does not slip one bit. Stock is only 7psi. Well then he said the valve body needs to be cleaned, I agree. Then he said I should just rebuild it and be done with it.............. Well that escalated quickly. This went from a $150 repair bill to $1500......


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## damian

you are all going the wrong way. the tps out of range will throw a code and affect the other shifts, the ignition problem was a low voltage condition feeding all shift solenoids that put the trans into default mode and threw shift solenoid codes,if either shift solenoids a and b were bad or sticking they would affect other ranges, the only clutch element that works only in 4th gear \od in a 4l80e is the fourth clutch, if this failed it would not affect the other ranges.the tcc solenoid wont affect od, if you have tow haul switch i would check it.otherwise my bet is 4th clutch failure or 4th clutch hydraulic circuit problem, either way it is over your head and better left to a good trans guy with a tech 2 scan tool and pressure gages. guessing almost always costs more.


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## MI Green

damian;1655350 said:


> you are all going the wrong way. the tps out of range will throw a code and affect the other shifts, the ignition problem was a low voltage condition feeding all shift solenoids that put the trans into default mode and threw shift solenoid codes,if either shift solenoids a and b were bad or sticking they would affect other ranges, the only clutch element that works only in 4th gear \od in a 4l80e is the fourth clutch, if this failed it would not affect the other ranges.the tcc solenoid wont affect od, if you have tow haul switch i would check it.otherwise my bet is 4th clutch failure or 4th clutch hydraulic circuit problem, either way it is over your head and better left to a good trans guy with a tech 2 scan tool and pressure gages. guessing almost always costs more.


tps never threw a code, no shifts are effected, and there is no ignition issue and there is no tow haul. The tcc does control overdrive because its not a overdrive band, its a torque converter lockup that is the literal overdrive. If you had a tow haul button all it would do is not go into torque converter lockup. It also has one in 3rd gear also. 4th is activated only when 2-3 or B solenoid functions correctly. Just because you think you know it all does not make it over my head because you don't have a clue. If you would checked my link you would of found out what you said even looks more stupid because after changing the filter and pan fluid and resting computer I have not had an issue unless I get the trans over 190 now and that took 30min of pure torturing the trans to get that temp. More than likely i have some crap in the valve body/screens disrupting flow for 4th. If you hunt on forums there are guys who have rebuilt whole trans thinking that would fix it, but some guys won't replace the valvebody in a rebuild only to have the same issues.


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## rjigto4oje

MI Green;1655383 said:


> tps never threw a code, no shifts are effected, and there is no ignition issue and there is no tow haul. The tcc does control overdrive because its not a overdrive band, its a torque converter lockup that is the literal overdrive. If you had a tow haul button all it would do is not go into torque converter lockup. It also has one in 3rd gear also. 4th is activated only when 2-3 or B solenoid functions correctly. Just because you think you know it all does not make it over my head because you don't have a clue. If you would checked my link you would of found out what you said even looks more stupid because after changing the filter and pan fluid and resting computer I have not had an issue unless I get the trans over 190 now and that took 30min of pure torturing the trans to get that temp. More than likely i have some crap in the valve body/screens disrupting flow for 4th. If you hunt on forums there are guys who have rebuilt whole trans thinking that would fix it, but some guys won't replace the valvebody in a rebuild only to have the same issues.


If you think it's a vavle body there's a guy on ebay shiftritetrans hes good I've used his valve bodys cheap has all updates just info hope it helps pm me if you need his number


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## 2COR517

MI Green;1655383 said:


> tps never threw a code, no shifts are effected, and there is no ignition issue and there is no tow haul. The tcc does control overdrive because its not a overdrive band, its a torque converter lockup that is the literal overdrive. If you had a tow haul button all it would do is not go into torque converter lockup. It also has one in 3rd gear also. 4th is activated only when 2-3 or B solenoid functions correctly. Just because you think you know it all does not make it over my head because you don't have a clue. If you would checked my link you would of found out what you said even looks more stupid because after changing the filter and pan fluid and resting computer I have not had an issue unless I get the trans over 190 now and that took 30min of pure torturing the trans to get that temp. More than likely i have some crap in the valve body/screens disrupting flow for 4th. If you hunt on forums there are guys who have rebuilt whole trans thinking that would fix it, but some guys won't replace the valvebody in a rebuild only to have the same issues.


Are you saying that OD in a 4L80 is actually just locking the TC and there are only 3 forward gear ratios?

And are you saying the T/H button simply prevents the TC from locking?


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## MI Green

2COR517;1655427 said:


> Are you saying that OD in a 4L80 is actually just locking the TC and there are only 3 forward gear ratios?
> 
> And are you saying the T/H button simply prevents the TC from locking?


There is a forth gear. It goes first, second, third, third torq lockup, 4th, lockup. So it feels like 6 gears on mine. When it locks it droppes about 200 rpm. so if you had a tow haul button it would keep it from that final lockup. 4th gear at 60 is about 2250 rpm and lockup is 2000 rpm. If you drop to thrid then your doing 2600 rpm.


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## MI Green

rjigto4oje;1655404 said:


> If you think it's a vavle body there's a guy on ebay shiftritetrans hes good I've used his valve bodys cheap has all updates just info hope it helps pm me if you need his number


I think it just needs to be cleaned. The filter just fell out when we took the pan off. The codes thrown were the tcc, the pressure control solenoid, and 2-3 shift. When I reset the computer it did not throw 2-3 shift when I got the trans to 190. So we are replacing the tcc, the pressure control, 2-3 shift, temp sensor, cleaning the valve body and checking the valve for 4th gear which can stick or the hole can even warp.


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## crete5245

Not true on only 1 clutch on in 4th... 

the fourth clutch, the forward clutch the intermediate clutch and the direct clutch.

See if there is any codes..

if you look at the clutch and band chart and the solenoid chart. the solenoid are on and off in different gears, it only has 2 solenoinds and it appears that they are working because you have the first 3 gears. solenoid A is on in first and solenoid B in on in 3rd and fourth so them must be working 

I would go for the fourth clutch, it is only used for fourth, the other clutches come on in the other 3 gears. 

just my 2 cents worth


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## MI Green

crete5245;1655545 said:


> Not true on only 1 clutch on in 4th...
> 
> the fourth clutch, the forward clutch the intermediate clutch and the direct clutch.
> 
> See if there is any codes..
> 
> if you look at the clutch and band chart and the solenoid chart. the solenoid are on and off in different gears, it only has 2 solenoinds and it appears that they are working because you have the first 3 gears. solenoid A is on in first and solenoid B in on in 3rd and fourth so them must be working
> 
> I would go for the fourth clutch, it is only used for fourth, the other clutches come on in the other 3 gears.
> 
> just my 2 cents worth


After everything I've read and mechanics I've talked to they have never suggested the forth clutch. If it was then I would not have 4th and torque lockup today. There is a valve that sits right of the 2-3 solenoid and they have been known to collect crap and keep it from going into forth or the hole warping and leak fluid. Also if it was 4th clutch then I would still have torque lockup in 3rd and I didn't. Also that does not explain losing lockup without loosing 4th like it did on Sunday when I got the trans hot. Also see above post for codes thrown.


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## crete5245

ok so let me get this right.. because I am confused from your thread title of "no overdrive"

You have fourth now and then and you have lock up now and then so it is not a complete loss of overdrive? Correct. 


the valve next to the solenoid you are talking about is the 3-4 shift valve

I would be looking in the valve body then rather than a hard component. You could drop the valve body and check all the valves to make sure they all move freely and are not scuffed. Also check all the solenoids while you have the valve body out.


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## MI Green

crete5245;1655555 said:


> ok so let me get this right.. because I am confused from your thread title of "no overdrive"
> 
> You have fourth now and then and you have lock up now and then so it is not a complete loss of overdrive? Correct.
> 
> the valve next to the solenoid you are talking about is the 3-4 shift valve
> 
> I would be looking in the valve body then rather than a hard component. You could drop the valve body and check all the valves to make sure they all move freely and are not scuffed. Also check all the solenoids while you have the valve body out.


Haha I stole this thread. This thread is 3 years old but I found it on Google relating to my issues and I was hoping the guy who started it would tell me what they did. My issue is that at 170 trans temp ill lose torque lockup and then 4th or both together. Once I reset the computer ill get them back until the trans gets hot again. I just got the truck and its got 210,000 miles and I doubt the fluid was ever changed. We changed it and changes the filter and now it has to be above 190 for me to loose it. The codes thrown are the tcc, pressure control solenoid, and 2-3 shift. Were changing those and the temp sensor, dropping the valve body and cleaning everthing. Since I've changed the oil I don't get 2-3 shift code. Yes the valve next to it is the 3-4 shift. From what I read I'd 2-3 and 3-4 act up you will lose 4th and toque lockup regardless of which one is the issue. I guess 2-3 is known for leaking around the o-ring. Also read my posts and you be up to speed


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## damian

Hey MI GREEN ,lock up is not overdrive, 4th is overdrive, the 4th clutch is the only element that is exclusively used in 4th on a 4L80E meaning no other range uses the 4th clutch other than OD. If the 4th clutch was bad it would only affect OD, any other clutch or element failure would cause multiple range issues,forward,direct,intermediate,and 4th clutch along with a roller clutch are applied in OD. How many 4l80E's have you overhauled anyway? Ive done plenty. Please If you dont know something its ok just dont give bad info to some poor slob trying to get through a tough problem, it only makes things worse.


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## MI Green

damian;1655629 said:


> Hey MI GREEN ,lock up is not overdrive, 4th is overdrive, the 4th clutch is the only element that is exclusively used in 4th on a 4L80E meaning no other range uses the 4th clutch other than OD. If the 4th clutch was bad it would only affect OD, any other clutch or element failure would cause multiple range issues,forward,direct,intermediate,and 4th clutch along with a roller clutch are applied in OD. How many 4l80E's have you overhauled anyway? Ive done plenty. Please If you dont know something its ok just dont give bad info to some poor slob trying to get through a tough problem, it only makes things worse.


Sounds like you need to eat your own advice because what's going on has nothing that you said. Its considered a 4 speed with overdrive. If you had a tow switch no way would it drop you down to thrid. You can't even run freeway speed with that.


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## damian

3 speed with overdrive plus lock up. 4-l-80-E : 4 speed, rear drive, tourque rating, electronic. you should quit while your behind.


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## 2COR517

Mr Green knows more about the 4L80 than the rest of us put together. Now it's a six speed lol. Plus, he can change the meaning of his sentences as needed. And T/H prevents TC lockup which I find very amusing, along with the inability to run freeway speeds with T/H button on. 

I would recommend more boost. The 6.5 heads love it.

Mr Green, can you post a pic of the Tow button on your 93?


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## MI Green

2COR517;1655731 said:


> Mr Green knows more about the 4L80 than the rest of us put together. Now it's a six speed lol. Plus, he can change the meaning of his sentences as needed. And T/H prevents TC lockup which I find very amusing, along with the inability to run freeway speeds with T/H button on.
> 
> I would recommend more boost. The 6.5 heads love it.
> 
> Mr Green, can you post a pic of the Tow button on your 93?


Heads are fine its the head gasket. 15psi is the limit and a studs fix the issue. Then you can push 20psi+, but its recommended to run thicker head gaskets which lower the compression to 20-1. Mine does not have a towhaul button and I said it didn't. The other guy thought I did. I never said it was a 6speed. I said its acts like a 5 speed becuase if you count the lockups it will lockup after 3rd and 4th. Plus running is 3rd is a great way to ruin this trans. Mine will run 220 with no sweat in 3rd no trailer. If you ran in third you could never do 70mph with a 4:10 ratio. Anymore from the unhelpful morons?


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## 2COR517

Now it acts like a five speed.

You should consider politics.......

And what's wrong with running a 4L80 in direct?


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## damian

6.5 liter engines are a whole other argument. My most replaced engine. too many issues to list.


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## MI Green

2COR517;1655831 said:


> Now it acts like a five speed.
> 
> You should consider politics.......
> 
> And what's wrong with running a 4L80 in direct?


I've said it a bunch of times. First, second, third, lockup, 4th, lockup. So sorry yes it feels like 6 shift for 4 gears. The problem is in drive with a 4:10 ratio your doing 2600 at 55 and 3500 at 65. 3500 is the yellow line on the tac. I got 9 mpg in drive last tank because I was forced to drive in it.


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## 2COR517

So it acts like a five speed and feels like a six speed?

I think I'm getting it. 

And again, what's wrong with running a 4L80 in direct?


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## Mike_PS

I'm thinking we can close this one out for now

thanks all


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