• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Considering a 4L80E in my 82 crew cab

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #1
Admittedly I've never been the biggest fan of auto transmissions. Considering that the truck currently has a good th400 in it and that my knee is only going to get worse over time, figure that staying auto isn't a bad idea. As a side note the current th400 doesn't coast when decelerating like normal, it stays engaged.

So what are some things to address with going from the th400 to a 4l80e? Staying with a mechanically injected diesel (Isuzu 4bd1t) and the np205 tcase due to being a passenger side drop and looks like I just found a PTO for it. 400-500ft/lbs of torque range. A decent amount of low speed/rpm rock crawling and offroad use. Towing wise it will stay under 26k combined weight and doesn't tow daily.

Considering adding another oil cooler and a external spin on oil filter mounted along the frame rail.
 

Will L.

Well-Known Member
Messages
7,684
Likes
6,586
Location
Boulder City Nv
#2
What you need to run a 4l80e -85e-90e is a stand alone unit to control it, and depending on the controller- it will change what is needed. Some people dont mind manual shift of a auto trans and just do manual, but daily driving it could get annoying.

Factory GM and AM General used a tcm, vssb, tps on the db2 and 2 wire engine speed sensor which could be done at crank sensor if you add a reluctor wheel or oil pump drive stye sensor.
 

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #4
There's ways to convert the np205 for a VSS (later models had it from the factory) and since I'll be stepping up to 35"s later anyways that is probably the route I'll go there. Add to it my speedo bounces some right now anyways (I get over 60 and it goes nuts haha).

The current 6.2 and the 4bd1t that's replacing it don't have the reluctor wheel/sensor or the tps, haven't looked into that mod for the 4bd1t. Considering the costs of initial purchase then reprogramming of a stock TCM the aftermarket option is looking like a viable option. Such as the Quickshift 4 that Leroy offers. 2 shifting tunes would be plenty with 1 being economy and the other towing. For offroading I'd just leave the trans in 1st like is currently done.

Any reliable ways to get some transmission braking out of these? Besides the th400 that is in the truck and an allison I've never had an auto that could do it. Didn't know the th400 could do it that well until towing from southern Utah up to here at a combined weight of roughly 19k and the trans kept the speed at 55-60mph while going down 4-6% grades. Other autos including other th400's always went into freewheel on me.

This won't be getting swapped in for awhile. 4bd1t and some other things will happen first so plenty of time to get the trans setup right before it goes in.
 

WarWagon

Well it hits on 7 of 8...
Messages
8,313
Likes
2,799
Location
AZ
#5
If it ain't broke don't fix it.

"Any reliable ways to get some transmission braking out of these (4L80E)? "

In a word, No! You are better off money-wise improving the brakes. I would suggest a different trans like an Allison esp. with a different engine in front of it.

The manual 3rd overrun clutch pack is weak. Like two plates instead of a pack and with the TCC locked up it slips while compression braking till it burns out. Even TC unlocked I burn them out. You get some fun "surge" as the clutch pack is getting toasted. There is no physical room to improve that specific clutch pack. I do run many miles with the said overrun clutch pack burned completly out to where it won't hold compression braking at all. (Engine drops to Idle RPM in manual 3rd, direct.)

This is one reason the TCC unlocks on throttle lift.

I find this kit amusing due to the weak clutches they want to use. Point of fact I have blown a 4L80E because of the OD roller clutch failing with an impressive muffler exploding type of "BOOM!" shifting into OD. The shrapnel went through the OD gearset. A bearing in the area also locked up and what failed first was unclear. https://www.sonnax.com/parts/4496-smart-tech-overrun-clutch-valve-kit
 

Will L.

Well-Known Member
Messages
7,684
Likes
6,586
Location
Boulder City Nv
#6
Ya kinda need to pick what is more and least important features. Like I am more and more considering a 6l80/6l90 inplace of my 4l80 because of the final overdrive of 0.667. And fuel mileage can pay for the upgrade. I know a couple guys in hmmwvs/hummer that went from th400 (1:1final) to 4l80e (0.75 final) and saw roughly 10% savings. Longer engine life instead of near wot on the interstate counts too.

Now the hmmwvs that makes ALL the difference because of gearing- many hmmwvs simply can not hit 60 mph ever being n/a 6.2 and th400.

And personally I dont tow a lot of weight coming down mountains so engine braking isn’t a huge factor for me.
When it does happen I am dragging weight, I just manually shift down gears. If I did, I would investigate engine exhaust brakes more - but not sure how bad that load is to the trans. There’s a guy lives a couple miles from me that is an ls engine addict, has a supercharged 6.0 and full built 4l85e in his 1972 1 ton chevy that he tows a tripple axle camper with and uses exhaust brake system on with no issues- but he doesn’t think twice to peel of thousand dollar bills for components either. Everything he owns is ls and 4l80

If you are constantly towing heavy loads in the hills, I cant imagine anything better than a stick.
But if you rarely tow a lot of weight, like once every other month- can’t beat the 4l80 design until you get to the 6l80 imo on lower powered engines.

That said if you have the power to waste and arent running empty or watching mpg- then Allison is the answer. But again depending how you use it most of the time. The guys with hummers that did the ally behind 6.5td I spoke to said a tad slower off the line, a tad lower rpm than the 4l80s hiway.
One guy compared it power wise from n/a to turbo going from 4l80 to allison.
 

WarWagon

Well it hits on 7 of 8...
Messages
8,313
Likes
2,799
Location
AZ
#7
You recall the no-drama grade braking the Allison in the 05 red truck had? Spinning the Duramax over 5000 RPM no-load... Made a bunch of noise testing the limits of the valve springs and little else.

FWIW Manual Trans clutches are designed to transfer torque one way only. So compression braking on them shortens their life as well. For example look at the drive straps on a clutch pressure plate. Generally the engine rotation is pulling on them not attempting to wad them up in cute bent up scrap metal.

Every time I slam on the exhaust brake with the Dodge everything from the differential to the engine steps out of it's ideal design life. It shuts things down in a hurry or holds the grades well. On an off ramp I can take the truck alone from 75 to 10 MPH in the length of the off ramp on the EB alone. Bit of work to quickly double clutch a slow shifting NV-5600 from 6-3rd keeping the RPM's up and below redline. It's just that clutches are $1600 wear items with labor vs. the cost of brake jobs. The exhaust brake on the Dodge is night and day over the mentioned 05 Allison without a exhaust brake.

So if you are going to use compression braking IMO get serious about it with and engine/exhaust brake or don't bother.
 

THEFERMANATOR

FRANKENBURBAN
Staff member
Lead Moderator
Messages
9,068
Likes
2,481
Location
ZEPHYRHILLS FL
Staff #8
IMHO, I wouldn't even consider a 6L80, or even a 6L90. Yes there is an aftermarket controller, but last I checked you could count on one hand how many places would sell it to you, and it's almost a grand for it. And all this controller does is act as a stand alone gateway that allows you to hook your own inputs up to it, program it to interpret the inputs, and it then outputs a high speed GMLAN signal that the 6L's internal TCM could read(still sketchy as to wether it outputs GM code, or if it engages the dvt controls in manual mode). And you still have to have the 6L's tcm programmed with an apropriate base tune for the application.

As to a 4l80e, I would look for a 4l85e from an 06+ duramax van. Tear it down, rebuild it with some quality clutches(blue plates work well for towing), put a hd2 shift kit in it, and I would be on the fence about a triple disc converter for what you're doing. Typically the 4x4 4l80e uses the speed sensor in the transfer case for the output speed sensor signal, but the same case is used for 2 or 4 wheel drive trannies. 4x4's don't have an output reluctor in them and a dummy plug where the oss goes.

Now 91-93 4l80e's in 4x4's used the reluctor in the trans instead of the transfer case. These reluctor's have gotten so scarce, that sonnax is now making replacements for $30 last I checked. So while the trans is apart, install a reluctor on the output drum, install a speed sensor in the output speed sensor hole, and connect your controller to this and you don't have to worry about any converting for a speed sensor in your transfer case.

As to controllers, I would go with the quick 4. I don't reccomend running line pressure at max all the time, and the jake's manual shift setup is awfully hard on the trans shifting at max line, not to mention max line pressure reduces oil flow through the cooler as it has to use the oil to maintain pressure instead of bypassing it to the cooler.

I know some point out the 4l80e's weakness's, but not everybody has those problems, and I know I've been surprised at how well the 4l85e has held up behind the duramax in vans. Wiring up the optishift won't be hard. All it really needs from the engine is an rpm signal(not mandatory, but strongly suggested) and a tps(and there is several cable hook up ones out there with everybody swapping these into cars with carbs), the rest can come from the trans.
 

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #9
You recall the no-drama grade braking the Allison in the 05 red truck had? Spinning the Duramax over 5000 RPM no-load... Made a bunch of noise testing the limits of the valve springs and little else.

FWIW Manual Trans clutches are designed to transfer torque one way only. So compression braking on them shortens their life as well. For example look at the drive straps on a clutch pressure plate. Generally the engine rotation is pulling on them not attempting to wad them up in cute bent up scrap metal.

Every time I slam on the exhaust brake with the Dodge everything from the differential to the engine steps out of it's ideal design life. It shuts things down in a hurry or holds the grades well. On an off ramp I can take the truck alone from 75 to 10 MPH in the length of the off ramp on the EB alone. Bit of work to quickly double clutch a slow shifting NV-5600 from 6-3rd keeping the RPM's up and below redline. It's just that clutches are $1600 wear items with labor vs. the cost of brake jobs. The exhaust brake on the Dodge is night and day over the mentioned 05 Allison without a exhaust brake.

So if you are going to use compression braking IMO get serious about it with and engine/exhaust brake or don't bother.
Yep I remember how the allison handled braking. If I can get similar out of another overdrive trans I'll be happy. The current th400 brakes well. With that load at roughly 19k, my friend was in his early 2000's F350 manual/single wheel, at a similar weight and had to use his brakes repeatedly down those grades to keep from rear ending me. Why this th400 brakes so well I don't know since others that I've driven had minimal to nothing for braking capability.

Going with an exhaust brake behind the 4bd1t is an option. But if the 4L80E can't survive braking on its own, how can it survive the increased braking from a exhaust brake?
 

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #10
IMHO, I wouldn't even consider a 6L80, or even a 6L90. Yes there is an aftermarket controller, but last I checked you could count on one hand how many places would sell it to you, and it's almost a grand for it. And all this controller does is act as a stand alone gateway that allows you to hook your own inputs up to it, program it to interpret the inputs, and it then outputs a high speed GMLAN signal that the 6L's internal TCM could read(still sketchy as to wether it outputs GM code, or if it engages the dvt controls in manual mode). And you still have to have the 6L's tcm programmed with an apropriate base tune for the application.

As to a 4l80e, I would look for a 4l85e from an 06+ duramax van. Tear it down, rebuild it with some quality clutches(blue plates work well for towing), put a hd2 shift kit in it, and I would be on the fence about a triple disc converter for what you're doing. Typically the 4x4 4l80e uses the speed sensor in the transfer case for the output speed sensor signal, but the same case is used for 2 or 4 wheel drive trannies. 4x4's don't have an output reluctor in them and a dummy plug where the oss goes.

Now 91-93 4l80e's in 4x4's used the reluctor in the trans instead of the transfer case. These reluctor's have gotten so scarce, that sonnax is now making replacements for $30 last I checked. So while the trans is apart, install a reluctor on the output drum, install a speed sensor in the output speed sensor hole, and connect your controller to this and you don't have to worry about any converting for a speed sensor in your transfer case.

As to controllers, I would go with the quick 4. I don't reccomend running line pressure at max all the time, and the jake's manual shift setup is awfully hard on the trans shifting at max line, not to mention max line pressure reduces oil flow through the cooler as it has to use the oil to maintain pressure instead of bypassing it to the cooler.

I know some point out the 4l80e's weakness's, but not everybody has those problems, and I know I've been surprised at how well the 4l85e has held up behind the duramax in vans. Wiring up the optishift won't be hard. All it really needs from the engine is an rpm signal(not mandatory, but strongly suggested) and a tps(and there is several cable hook up ones out there with everybody swapping these into cars with carbs), the rest can come from the trans.
My stated towing weight isn't constant by any means. Not a hotshot or farm truck. When I tow it tends to be on the heavier side just not outside of the trucks' capacity.

What are the downsides to a 1999 model year 4L80E? Guy I know sent me a message today that he has one available for cheap.
 

WarWagon

Well it hits on 7 of 8...
Messages
8,313
Likes
2,799
Location
AZ
#11
The conclusion of my rant about the very few weaknesses of the 4L80E was: If you are dropping a 4L80E in "Forget about engine braking!"

If this is a box you want to check I suggest a different transmission. Nothing wrong with getting on then off the brakes esp. if they are upgraded brakes. Again the "cost" of brakes, as long as they don't fade, is way cheaper than engine braking caused wear.

I have gone through 3 overrun clutches and one of them was in the 1995 3/4t Suburban. It would surge slip from the vehicle's weight alone as it didn't tow often at all.

The OEM Torque Converter Clutch is also weak and has trouble holding the diesel torque over the miles esp. if you want to lug it. Most of the transmissions I have gone through have been from the TCC slipping. The last rebuild I put off by replacing the TC with a Yank. It's now slipping 1st and reverse, but, got years and a lot more miles out of it. IMO an upgraded TC clutch is a good idea if possible.
 

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #12
Relying on just the axle brakes isn't a good idea in my opinion/experience. Been working as a mobile heavy diesel mechanic since I got out of the military and every 18 wheeler at the bottom of the hill that crashed or was on the runaway ramp were relying completely on axle brakes.

Granted not near the weight, but some braking capability from the drivetrain is necessary to me. If the 4L80E can do it with a few reasonably priced mods then that's fine for me. It is based off the th400 (which is currently doing this great). I know the current trans was built before I got it.

Main goal with a trans swap is to get the truck up to 70mph cruising at lower rpm while still having the same capabilities it currently has. Right now it's spinning 2600rpm for 60mph.
 

WarWagon

Well it hits on 7 of 8...
Messages
8,313
Likes
2,799
Location
AZ
#13
I would have paid good money for a mod to overcome the weak overrun clutch for compression braking if there was one available. If you find a mod, and I have looked and asked the trans builder of mine, please let me know. I have done plenty of engine braking regardless of reduced life. I can't count on the 4L80E to hold when I need it let alone do enough braking through an unlocked converter to matter. (No complaints of getting things moving with a 4L80E... And there are certainly worse crapmissions out there. )

The TH400 is a 3 speed and IMO the addition of OD is why this weakness is in the 4L80E. After all the overrun clutch is in the OD section...

Maybe a GV overdrive would be a better idea with the current TH400?

Here is the 4L80E layout and some pics of the tiny clutch I keep ruining: http://www.superchevy.com/how-to/transmission/1708-building-a-4l80e-to-handle-more-torque-and-power/
 

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #14
Going off of gear vendors website info I think it might actually be worse regarding braking being that they state 'do not use any engine brake devices with the gear vendor engaged'.

That link mentions they used upgraded plates and clutches in the overrun clutch from Raybestos.

Why not go to a better locking torque converter such as a triple disk that Ferm mentioned?
 

WarWagon

Well it hits on 7 of 8...
Messages
8,313
Likes
2,799
Location
AZ
#15
My trans builder didn't think that improved frictions would help because there isn't enough of them (2), small friction area, and no room to add more to get some real holding power there. Perhaps higher line pressure could help with compression braking. It would cost 2x what I pay for a rebuild to use better frictions and at 50K miles a pop I may use better on this rebuild.

The Triple Disc Yank I have will lug the engine to a near stall before it unlocks in 1st gear if I leave the TCC override switch on. It solved that weakness. Cheaper multi disc converters out there, yes.
 

THEFERMANATOR

FRANKENBURBAN
Staff member
Lead Moderator
Messages
9,068
Likes
2,481
Location
ZEPHYRHILLS FL
Staff #16
My stated towing weight isn't constant by any means. Not a hotshot or farm truck. When I tow it tends to be on the heavier side just not outside of the trucks' capacity.

What are the downsides to a 1999 model year 4L80E? Guy I know sent me a message today that he has one available for cheap.
An early 99 isn'tbad, it just doesn't have the factory improvements in it. There was a wider band installed, solid shafts, and a few other improvements that showed up mid year 99(I believe they made them for the new 6.0L LS engine).
 

THEFERMANATOR

FRANKENBURBAN
Staff member
Lead Moderator
Messages
9,068
Likes
2,481
Location
ZEPHYRHILLS FL
Staff #17
The conclusion of my rant about the very few weaknesses of the 4L80E was: If you are dropping a 4L80E in "Forget about engine braking!"

If this is a box you want to check I suggest a different transmission. Nothing wrong with getting on then off the brakes esp. if they are upgraded brakes. Again the "cost" of brakes, as long as they don't fade, is way cheaper than engine braking caused wear.

I have gone through 3 overrun clutches and one of them was in the 1995 3/4t Suburban. It would surge slip from the vehicle's weight alone as it didn't tow often at all.

The OEM Torque Converter Clutch is also weak and has trouble holding the diesel torque over the miles esp. if you want to lug it. Most of the transmissions I have gone through have been from the TCC slipping. The last rebuild I put off by replacing the TC with a Yank. It's now slipping 1st and reverse, but, got years and a lot more miles out of it. IMO an upgraded TC clutch is a good idea if possible.
The clutch isn't that weak, it's the apply piston that flexxes when applied that is the problem. That's why most aftermarket converters put a weld ring around the piston to stiffen it and prevent failure. Or for an extra $125 you can get one with a billet apply piston.

Going off of gear vendors website info I think it might actually be worse regarding braking being that they state 'do not use any engine brake devices with the gear vendor engaged'.

That link mentions they used upgraded plates and clutches in the overrun clutch from Raybestos.

Why not go to a better locking torque converter such as a triple disk that Ferm mentioned?
Yes, the gear vendor cannot be engaged with an engine brake, it's the reason why they will not sell one to go behind an allison is grade braking would slip it. The gear vendor is a laycock overdrive unit which was used by volvo and several others. It's a great unit, but it uses a cone clutch in it. A cone clutch is tapered and is designed to pull in under load. They shift very smoothly and since they pull in tight under load, very little pressure is needed to engage one, and the bigger the load, the tighter it holds. BUT, if you load it in reverse, the cone clutch tries to disengage and push apart, so it has very little holding power in reverse. I believe if you disengage the gear vendor, you can use an engine brake, you just can't do it with the unit engaged.
 
Last edited:

red

stubborn Texan displaced to Utah
Messages
1,589
Likes
418
Location
Eagle Mountain, Utah
Thread starter #18
An early 99 isn'tbad, it just doesn't have the factory improvements in it. There was a wider band installed, solid shafts, and a few other improvements that showed up mid year 99(I believe they made them for the new 6.0L LS engine).
For my application would you consider those upgrades (between a stock 99 and a stock 2000+) necessary? 400-500ft/lbs of torque, no boosted launches and I usually drive pretty easy on the truck.

Where to get the upgrade and better quality rebuild parts/torque converter, including the billet apply piston for the overrun clutch? Reason I ask is I can get that 1999 model 4L80E with stock harness and tcase for $500 and although new to auto's have no problem diving into a rebuild.
 

THEFERMANATOR

FRANKENBURBAN
Staff member
Lead Moderator
Messages
9,068
Likes
2,481
Location
ZEPHYRHILLS FL
Staff #19
For my application would you consider those upgrades (between a stock 99 and a stock 2000+) necessary? 400-500ft/lbs of torque, no boosted launches and I usually drive pretty easy on the truck.

Where to get the upgrade and better quality rebuild parts/torque converter, including the billet apply piston for the overrun clutch? Reason I ask is I can get that 1999 model 4L80E with stock harness and tcase for $500 and although new to auto's have no problem diving into a rebuild.
I was talking about the billet torque converter piston, not an overrun piston. But I see SONNAX has a kit to strengthen the over run clutch in the 4l80e/4L85e. You can install the updates, but it's going to cost you more than $500 for the pieces. That said, there's nothing really wrong with the earlier units. The 06+ 4l85e out of the duramax van's would be ideal. It has all the factory improvements, and about as good of pieces as you can get inside it already.
 

Will L.

Well-Known Member
Messages
7,684
Likes
6,586
Location
Boulder City Nv
#20
@THEFERMANATOR
Not to be rude and step on his thread. But my Hummer has db2 and GM tcm controlling it. Is it just install the 4l85e inplace of the 4l80e? Or is there programming, etc needing to be done for the 06 van trans?
 
Top