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4l80e time for a new one

ak diesel driver

ak diesel driver

6.5 driver
Messages
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Location
alaska
So my ?s are

1. Is there any good tranny builders ,preferably in the northwest, who would build a good solid tranny built for towing?

2. What upgrades should I be asking for or about?

3. Is there anyway to do the TCC lockup mod like the obd1s can do for obd2?Is it possible when I get a chip to have something changed so this mod will work?

4. What kind of price range should I expect?

5. Anything else you can think of?
 
I know you can get a gm rebuild with all factory upgrades for about 2300 + core(though scarce). 50k mile warranty, and shiny. my opinion is to just keep it cool-heat kills any of em--------as ak's summers go
 
I take it when you say a GM rebuild you are talking about the stealer? 50k is a pretty good warranty best I found at any of the local shops is 2 yr 24k. May be cold here in the winters but it can get pretty hot here also I've seen an occasional mid 90s, just not for very long. So I plan on putting a big cooler on it and was thinking of running the oil thru it and then thru the cooler in the rad to help warm it up when its really cold. Think it matters which I go thru first? I was also thinking about an upgraded TC.
 
My kids are getting old enough that I am thinking about fixing up my old 26' travel trailer. And I have pulled a mini excavator which ways 18000lbs but that would be a rareity. The biggest reason I want the TCC mod is most of the roads here are 2 lane and can be rough so I will see alot of hunting between OD and 3rd. Be nice to pull it into 3rd and lockup.
 
Well I bought a GL4 chip today. Talked to Bill and he said with my symptoms that he thought that it would put off my rebuild. My symptom was it would slip in third under load but only when i throttled it. He also said that they were working on a TC mod for the OBD2 not a big priority but was in the works. Told me if it comes out later that I could get an upgrade without having to buy a whole new computer. I've been wanting a chip anyway so it was a good excuse.:D
 
good, one thing that has made a big difference is a secondary cooler. I put a 28k lb gvwr cooler in front, then moved factory cooler under bed (TDoc has a thermostat fan on his) in series. I would recommend a fan. really helps keep fluid cool, thereby extending tranny life. according to gmtdscan normal temp in summer towing is around 180 empty about 120.

yeah, the dealer has a pretty good deal, a stronger tranny would be great, however-----for the price and warranty, I couldn't beat it. I figure since I will take care of it, it should last a lot longer than the one that wasn't taken care of that came with the truck.
 
Well after spending a chunk for GL4 I decided to limp along till next winter and then I'm going to dive into it myself. Already bought some specialty tools off fleabay. If anyone knows of something in particular that I need for this job let me know.
 
Got my GL4 installed today so far no slippage. Haven't tried towing yet but I don't know if I will I'm just trying to get by until next winter when I can rebuild the tranny myself.
 
So here I am a year later still running this same tranny that everyone I talked to said needed a rebuild and wouldn't last much longer. I decided to drop the pan and change the filter. I bought the truck with 60k on it and never have touched it, the tranny I mean. I expected to see black as coal oil and lots of "stuff" in the pan. Oil was defineatly dark but didn't seem "burn't". Hardly any residue in the pan which really suprised me.The magnet had less than 1/8" of stuff on it and I did find a few pieces of brass about the size of a bb but they were very very thin. So I finally found a tranny tech who would talk to me and he said he would try and change the EPC selenoid. So I got one for $67 and put it in. So far I haven't driven it enough to come to a positive conclusion, but shifts do "seem" firmer. So I guess my ? for you guys is how much rpm change do you get when towing. Scenario 45mph no TC lockup pulling 6-8k. Step on the throttle and can watch rpms raise 800+rpms before I back off cause I'm worried about slipping. When I say step on the throttle I don't mean floor it just giving it some to accelerate. I'm wondering if it's just me or is this normal. Most of the towing I've done has been with a manual trans.
 

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So another update the ecp selenoid and filter change definately helped. Towed 10k before I took my trip to Fairbanks and I could still get some slippage but with 5-6k on the way back from fairbanks and working it hard with hills and a headwind it did just fine.
 
You can install a shift kit,it adresses all the hickups.
I done rebuild a 4L80 last fall and put the kit in as well,wont be easy putting the kit in with the tranny in the truck though.
Rebuilding these tranny's aint that hard either,no special tools needed,just have to buy(pricy) or fashion a sleeve for installing 2 clutch pistons.
 
At this point I already have an 03 tranny to rebuild so I'll just leave this be for now and concentrate on the 03 tranny. Just wish I could've got some good info on my tranny 50k ago. Standard reply was time for a rebuild I'm really getting to dislike tranny guys. They try and make you think your not smart enough to fix your own.
 
been there done that,today my vision is,if other people can build it,i should at least be able to repair it or in some cases modefy so it is better than stock.
 
After reading your posts:
I wouldn't jump to a rebuild just yet.
If you are slipping in third gear it could be simple, simple, simple.


The debris in the pan tells me you have several things to look into.
Depending on the year of the truck.
If you have a Throttle position sensor. Ensure it is adjusted correctly. Even if it is not throwing a code the pressure in the transmission may not be enough for 3rd.
The PCS solenoid is a good call. So is the 1-2 and 2-3 shifting solenoids.
A good pin to pin check at the passthrough connector.

Solenoids can wear out over time.
Tech shops were supposed to pressure test solenoids. There is a special tool designed for that purpose.
You place the solenoids in, actuate the solenoids and see if they hold pressure.
Replace both the 1-2 and the 2-3 and the pressure control. As a matter of fact the TCC solenoid as well.
Make sure you know year specific.
Chances are you might not have slippage in third.
 
I wonder what Heath specifically would have done to address this slip. And when you say slip what do you really mean? Are RPMs surging (jumping 200rpm) prior to landing in 4th? Or do you mean when its in second and accelerating, it shifts into 3rd, but then feels like it finishes the upshift 2 seconds later when RPMs drop.

That second to third akward moment is the TCC locking up, where it seems like its not engaging in third, but it did then TCC locked up and dropped RPMs.

A slip is a jump in RPMs prior to shifting. If its doing that between 2 and 3 that is odd, but between 3 and 4 is common. Thats because TCC is locked in 3rd and has to unlock to make the upshift. This is one reason I dont like the idea of a TCC override switch. The TCC solenoid should be replaced if this is happening with stock PCM. The Sonnax Sure Cure kit is also supposed to address this.

The slip happens when TCC unlocks and you still have your foot into the pedal. The way this is addressed is that GM cuts fuel as RPMs increase for any given pedal percentage. THis way you start accelerating slightly slow and fuel rate is lower when TCC unlocks to make the shift.

Tranny pressure is also related to pedal percental, %TPS as the general eluded to. At higher TPS the tranny climbs in pressure significantly, so you probably have no slip if you left it close to WOT.

A PCM reflash can cause more slip if the fuel curve is modified so that less pedal gives you more fuel, because then your going faster with less tranny pressure. Or if the fuel curve does not drop as fast of a rate as the stock one did. A PCM reflash can help if the builder takes this all into account, drops fuel faster, doesnt increase fuel rates at low pedal percentages, or increases tranny line pressure at low pedal percentages.

Other things PCM reflashers should be doing, but I havent seen specifially is lowering the top kickdown speeds, and increasing the kickdown pedal percentage needed. this way you are more likely to maintain OD. They can also lower the downshift speeds, so it wont downshift unless you put the pedal in more. This would make the system just work better rather than needing a TCC lockup mod.
 
My shifts are fine it's actually slipping after the shifting is all done. Really mushy feeling and rpms will go up alot with throttle application. Way more than I think it should. If this tranny didn't have 226k on it I'd look at it a little more seriously.

What this setup really needs is a tow haul mode button. If you adjust the kickdown so it works good for everyday driving then it won't shift soon enough when towing.
 
Pressure test that dammm transmission. There is a pressure port on the driver's side. Run a fitting, line and pressure gauge. Make the line long enough so you can see it while driving.
There should be around 85-100 in the forward ranges.
The reverse will be higher.
If the pressure changes from 2nd gear to third or 4th then you will absolutely know if you need further maintenance.
If the pressure is low then there could be internal leakage.
It could be something as simple as the transmission Control valve body plate wearing out because the check balls are harder than the plate.
It can also be one of the servos leaking.
If you didn't see clutch material that is a good sign.
Even shifting solenoids can wear out.
The pressure control solenoid. PCS or whatever they call them usually is stuck off or stuck on. The less the amperage to this solenoid means higher pressure. The computer controls the amperage.
Long before most think of rebuilding a transmission a check at the throttle position sensor. A misadjusted sensor means the line pressure is not being adjusted to proper pressure.
The computer needs two inputs for engine load. One from the throttle output and one from the RPM.
You can also trick the 2-3 shifting solenoid into engaging and perform a stall test. When doing it you are checking for clutch application. Any slipping can mean the any clutch holding is not happening.
 
Our TPS is actually the accelerator pedal with 3 sensors, and it only needs two to be working correctly. And the computer knows if those are out of whack usually if they arent agreeing. You cannot adjust them.

The tranny main line pressure is set from that pedal position (%TPS), and speed (MPH). The more pedal the more pressure and the stock PCM program has the same curve at any speed. The scanner can show what the desired is and you can compare to gauge, and scanner can even set it higher to make sure it will actually change with desired settings.

soft feeling in the tranny could be it, or it could just be an underpowered engine, from fuel starvation or poor combustion at higher fuel rates from bad injectors, low compression or low boost.
 
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