4L80E & TH400 Tech.

[clinebarger]

I thought I would share some Tech for 4L80E & TH400 transmissions.
These units have very few weaknesses. But can be made better with a few mods.

Dual Feeding the Direct Clutches is hands down the best mod you can do.


From the factory the Direct apply piston is divided into 2 separate sections. In factory form, 3rd gear oil only uses the smaller of the 2 sections to apply the Direct clutches.

However, Reverse uses both areas to apply the Direct clutches.

The first diagram is D3/D4...Directs clutches applied.
Second diagram is Reverse.

[clinebarger]

The only thing needed is a parking pawl cup plug, Comes in every 4L80E/TH400/TH350/700R4/4L60E rebuild kit.

Use the Cup Plug to block the Reverse passage in the case. (the passage to the right of the Center Support Bolt) I recommend using some type of Retainer Compound on the OD of the cup plug & let it set overnight.

[clinebarger]

Omit the lip seal in the direct drum & the second sealing ring on the Center support.

[demian5]

Originally Posted by clinebarger

The only thing needed is a parking pawl cup plug, Comes in every 4L80E/TH400/TH350/700R4/4L60E rebuild kit.

Use the Cup Plug to block the Reverse passage in the case. (the passage to the right of the Center Support Bolt) I recommend using some type of Retainer Compound on the OD of the cup plug & let it set overnight.

Is this a good thing to do if you have to pull the valve body for any reason?

I have to pull my VB to replace the plastic piston on the VB.

Any other suggestions while I am in there?

Its an 86 C20 with 57k OG miles. Never been apart. Shifts great, just no engine braking in 2nd only.

[clinebarger]

Originally Posted by dfarr67

Thanks, do I rebuild what I have or is there any merit going with the earlier gun drilled shafts with a different lube circuit? Not racing just a nice meduim duty towing/4x4/street build behind a torquey 385 TPI.

Originally Posted by dfarr67

A few other questions as well.

- My mechanic has had to replace a few trans alum oil cooler lines on newer GM trucks as the crimps let go on the rubber hose portions. My truck is a 1989 K1500 with 700r4- would I order 1998 K2500 454 lines (are these steel?), or make my own, my oem steel lines never gave me any trouble.

- Regarding frictions are all HE created equal or try to find BW rather than Alto or Raybestos?

Use the 2005 core, The early "Conventional Lube" & Late "Center Lube" both lubricate well.....

The only Achilles Heel on the "Center Lube" unit is if the AFL filter cracks, The Case Bushing, Case Thrust, & Output Bushing will starve for oil, Always 100% replace the AFL Filter & don't crack it during installation.

DO NOT mix parts between conventional lube & center lube units......Sure, There are parts that swap, Like the O/D unit, Forward Drum, & Direct Drum but few other pieces!!

A early drilled Main Shaft will probably be OK in a Center Lube unit, But a Solid Main Shaft in a early unit would be disastrous!!
I've never had the guts to try a early main shaft in a late unit, So even that is speculation.

It's not the line material or the crimp for that matter behind the failures, It's the Junk thin wall hose GM uses & cold temps aggravate the issue, When I come across this failure on 4L60E/4L80E, I split the crimp 180 degrees with a cut off wheel, Remove the old hose & crimps, Replace the hose with Gates 400psi Trans Cooler hose & use "Pinch Clamps".

Hose failures are more of a Allison 1000 problem because they run 3X the cooler line pressure of a Hydramatic, Maybe this is what the mechanic is alluding to??

I would just run some AN Braided hose on a '89 as the later "Center Lube" lines will be Quick Disconnect & not compatible with your radiator or auxiliary cooler. Get the correct fitting for the rear cooler line port!

I use Borg Warner frictions because that is what GM uses, If they could get away with cheaper frictions.......I'm sure they would.
I use some Raybestos specialty frictions from time to time. I'm sure their stock replacement stuff is OK.

Alto has screwed me to many times with their JUNK, I had one of their Red Bands completely delaminate & ruin a $100 drum & they wouldn't even warranty the Band.

[clinebarger]

Originally Posted by demian5

Is this a good thing to do if you have to pull the valve body for any reason?

I have to pull my VB to replace the plastic piston on the VB.

Any other suggestions while I am in there?

Its an 86 C20 with 57k OG miles. Never been apart. Shifts great, just no engine braking in 2nd only.

NO, You have to remove the center seal in the Direct Drum as well!

There are Shift Kits that "Dual Feed" the Directs without removing the seal.

Trans Go 400-1&2, And Trans Go 400-PRO.
The 400-PRO comes with a Aluminum 3rd Accumulator Piston.

[dfarr67]

Thank you for the replies.

Is this piece a straight replacement in the newer units or does it require other changes.

http://www.ebay.com/itm/111453434374...%3AMEBIDX%3AIT

Would these fittings restrict volume of oil flow? I want to use just regular fittings not the factory snap in.

http://www.ebay.com/itm/231278300872...%3AMEBIDX%3AIT

At first I thought- yes I am capable of doing a 4l80e, not so much anymore...more so the looming specter of taking the trans out again because I missed something.

Clineberger- I like the idea of the Sonnax reamer and sleeve- does your shop have these, could I ship valve body for service. I cannot justify buying that particular kit and don't like the wearing characteristics of the cheaper technique.

The damaged oil cooler lines were not on a Allison trans, and yes this is a cold climate here, I just didn't see the cooler lines as a maintenance item. Either way I think hard line is a lot of work but a good quality hydraulic line will fit the bill.

[Clyde65]

Thanks Cline!

[clinebarger]

Originally Posted by Clyde65

Thanks Cline!

Your welcome, Hopefully it helps someone.



The next weakest link is the Intermediate Sprag....


4L80E's have a 34 Element Sprag from the factory, And are pretty stout.

'69 & earlier TH400's use a 16 Element Sprag.

'70 & up TH400's have a 8 Element Roller Clutch. Under 450HP applications will be OK, A lot of HP & torque, & Harsh 1-2 shifts will kill this Roller Clutch.

If you have a 4L80E, Your good, Though I would replace the sprag with a new Borg Warner.
If you have a Early TH400 (Direct Drum), All you need is a 34 Element Sprag for a 4L80E.
If you have a Late TH400 (Direct Drum), Buy a Early Drum or a 4L80E Drum.

Custom 36 Element Drums are available, Not needed on most anything street driven.

**NOTE, Do not mix the Sprag Races on these 3 drums!!!! The 4L80E Race is taller for the 4 Intermediate Clutches vs 3 on a TH400 & will not fit on a TH400 Direct Drum. Early TH400 Drums are getting scarce, Buying a Complete 4L80E Drum is the best option.

This is a pic of a 4L80E Direct drum with a 34 Element Sprag.

[whitels1]

Thanks Cline! I'm getting ready to swap in an 86 TH400 and this is just what I needed

[clinebarger]

Originally Posted by whitels1

Thanks Cline! I'm getting ready to swap in an 86 TH400 and this is just what I needed

Why a TH400? I only ask because you have a 5.3L. Not being cynical at all....Just curious because your PCM is capable of controlling a 4L80E.

[whitels1]

Cost really, I'm getting the TH400/NP205 combo for less than the price it would be for a 4l80E/NP205 Adapter.

[clinebarger]

Originally Posted by whitels1

Cost really, I'm getting the TH400/NP205 combo for less than the price it would be for a 4l80E/NP205 Adapter.

Cool, Are you going to tear the TH400 down & rebuild?


Ok, Back to the business at hand.

Separator Plate Hole sizes, We will start with the TH400. These are suggestions. The bigger the feed hole....The quicker & Firmer the shift will be. Clutch clearance affects this as well! A loose clutch stack-up will cause a firmer shift than one that is set-up tight.

2nd Feed Hole, 125" Max.

3rd Feed Hole, 140" is good if your Blocking the 2-3 Accumulator.
If leaving the Accumulator functional, .175" is where I like it.

Before anyone gets their panties in a wad over such a big 3rd feed hole......The plate in the pic is from a '70 Cadillac TH400 that had a factory 6 friction Direct Drum & has a .175" 3rd feed hole stock.

**Note, Removing checkballs will render feed hole sizes useless!

[whitels1]

Originally Posted by clinebarger

Cool, Are you going to tear the TH400 down & rebuild?

Yes, even though it only has 50k miles on it and in good working order, I still feel like it would be beneficial to beef it up now, rather than later. Besides it would make for good video and it's something that I have been wanting to do for a long time.

[clinebarger]

Blocking the 2-3 Accumulator. (TH400)

You will need a 5/16-18 tap & a 5/16" set screw.
Tap it just deep enough for the set screw to seat good.

The red arrow is the accumulator feed hole that needs to be tapped & plugged.

[clinebarger]

4L80E Separator Plate hole sizes. This unit is kinda picky about clutch feed hole sizes & don't need to be as big as a TH400.

If your running a stronger Pressure Regulator spring or a larger Boost valve (Or both)....Be conservative on feed hole sizes.....Mainly 2nd to keep from shocking the Intermediate sprag.

"Stall" Of the converter has a huge effect on shift feel....The Looser the converter...The softer the shifts will feel, Meaning you can run bigger holes.
Using a stock converter....Again, Be Conservative!

2nd Feed Hole, .085" to .125"
3rd Feed Hole, .093 to .150"
4th Feed Hole, .085 to .093"

[-TheBandit-]

clinebarger, thank you for the great tech advice!

Originally Posted by clinebarger

Blocking the 2-3 Accumulator. (TH400)

You will need a 5/16-18 tap & a 5/16" set screw.
Tap it just deep enough for the set screw to seat good.

The red arrow is the accumulator feed hole that needs to be tapped & plugged.

When blocking the 2-3 accumulator feed port, should you remove the spring under the accumulator piston?

Originally Posted by clinebarger

3rd Feed Hole, 140" is good if your Blocking the 2-3 Accumulator.
If leaving the Accumulator functional, .175" is where I like it.

Before anyone gets their panties in a wad over such a big 3rd feed hole......The plate in the pic is from a '70 Cadillac TH400 that had a factory 6 friction Direct Drum & has a .175" 3rd feed hole stock.

Regarding blocking the 2-3 accumulator vs. leaving it functional and using a larger 3rd feed hole, do you have a preferred approach? What are the tradeoffs?

[picklito]

Originally Posted by clinebarger

Separator Plate Hole sizes, We will start with the TH400. These are suggestions. The bigger the feed hole....The quicker & Firmer the shift will be. Clutch clearance affects this as well! A loose clutch stack-up will cause a firmer shift than one that is set-up tight.

2nd Feed Hole, 125" Max.

1970 TH400: I'm at .125" using a new plate from Superior and all 6 original check balls. I want to go a little firmer... enlarge the hole or start removing check balls?

[clinebarger]

Originally Posted by picklito

1970 TH400: I'm at .125" using a new plate from Superior and all 6 original check balls. I want to go a little firmer... enlarge the hole or start removing check balls?

Do you know what style Direct Drum you have...Roller Clutch or Sprag type???

A Intermediate Roller is quite a bit weaker than a Intermediate Sprag, A '70 model "should" have a Sprag type Drum.

Roller Clutch....NO larger than .125"! If you do.....The risk of Roller Clutch failure is high.

Sprag....You can go out to .140".....With the 2nd Clutch checkball in place & a Active 2nd accumulator.

Do not remove checkballs....The Reverse checkball being an exception when dual feeding the directs.

The checkballs job is to route clutch feed oil through the orifice, If you remove it, Feed oil will freely pass through both the orifice & the hole the checkball is suppose to check. You end up with a effective feed hole size of over .300" or larger.
I have fixed too many broke units with B&M/TCI shift kits (That delete checkballs) to ever recommend doing this on a street transmission.

The ONLY time I omit CB's other than reverse, Is on Reverse Pattern Manual Valve Body (RPMVB) units, And RPMVB with a Trans Brake. However these competition units don't take a standard plate, They only have the Feed holes, The CB holes are eliminated.

Here is a pic of a RPMVB/Trans brake plate to show the huge difference from a standard plate.

[Dieselwrencher]

Clinebarger, I was wondering if you would share what I need to get to build a 4L80E to hold 600hp reliably. The trans is from a 96 truck. Will that be an issue? The trans is going behind a 2000 5.3 in a 40 Ford with a mid frame S400 turbo and I'm sure it'll see some abuse. I'm going to use the GM PCM to run it so do I need to change any connectors to a later one or is it cheaper to get the adapter harness? Thanks for your time, Ryan.

[clinebarger]

Originally Posted by Dieselwrencher

Clinebarger, I was wondering if you would share what I need to get to build a 4L80E to hold 600hp reliably. The trans is from a 96 truck. Will that be an issue? The trans is going behind a 2000 5.3 in a 40 Ford with a mid frame S400 turbo and I'm sure it'll see some abuse. I'm going to use the GM PCM to run it so do I need to change any connectors to a later one or is it cheaper to get the adapter harness? Thanks for your time, Ryan.

A '96 model will work fine!, It actually has a better/stouter Overdrive Sprag assembly than the '97 & up 4L80E's, However '91-'96 models generally have a weaker 16 Element Intermediate Roller Clutch VS a 34 Element Intermediate Sprag, If yours has the 16 Element Roller Clutch.......At 600hp, You will have to upgrade the Direct Drum/Intermediate Sprag!

On the wiring, Your going to use a 2000 chevy truck 5.3L/4L60E harness? If so, You can just swap some wires around at the Trans Plug & PCM & run 2 Input Speed Sensor wires, The Trans plug will reach.....Simple stuff. Now if your running a 4th gen F-body harness, The Plug will not reach & buying a adaptor harness is best.

Ok, On to the parts list...

Of course you will want to "Dual Feed" the Directs.

Billet Input Shaft, http://www.ckperformance.com/View/CO...ON-INPUT-SHAFT If your planning on running drag Radial/Slicks this is absolutely necessary!

Billet Forward Hub, http://www.ckperformance.com/View/FO...ZED-CLUTCH-HUB Recommended for any Boosted application.

Spiralock Intermediate Clutch Snap Ring, http://www.ckperformance.com/View/TH...UTCH-SNAP-RING

Late 4L80E Direct Drum/Intermediate Sprag, http://www.ckperformance.com/View/6-...L-RETAING-RING

Actuator Feed Limit repair kit, http://www.transgo.com/products.php?...dcountview=Yes

AFL Filter End Plug, http://www.sonnax.com/parts/2031-afl...lug-o-ring-kit

Large Ratio Boost valve, http://www.sonnax.com/parts/2170-lin...re-booster-kit

Line to Lube Pressure Regulator Valve, http://www.sonnax.com/parts/1989-lub...egulator-valve

TCC Regulator Valve, http://www.sonnax.com/parts/2025-tcc...ator-valve-kit

Torlon Check Balls (you need 8), http://www.sonnax.com/parts/1689-checkball

No Walk Case Busing, http://www.sonnax.com/parts/1981-case-bushing Requires careful installation, Cannot use a typical bushing driver...The bushing will break!

Rebuild kit with Frictions, Bands, Steels, Bushings, Seals etc. http://www.ebay.com/itm/4L80E-Transm...-/360815789616
"HEG" High Energy Graphite Carbon frictions are superior to "Red"/"Blue"/"Tan" materials.

Alto rates their proprietary "Red Eagle" friction material as the "Best". Raybestos rates their proprietary "Blue Plate Special" friction material as the "Best". These 2 companies both make HEG frictions as well, But have to pay royalties too Borg Warner because Borg Warner holds the patent on High Energy Graphite Carbon friction material. Alto & Raybestos wants to sell their proprietary frictions because they make the most money that way, Not what is best for the end user!

[softballnrd27]

Clinebarger-
I am currently looking for a decent 4l80e to build up and I can only find the 91-96 cores in the price range I am comfortable with. It will be behind a 5.3 and will eventually have a turbo or 2. My current th350 wont hold fluid and is slipping real bad so I need to replace it. Can I control the 91-96s with the 03 computer? Can I add an aftermarket floor shifter later on down the road? I plan to do everything you have listed, can you explain why? Just for my knowledge, not questioning you at all.

[clinebarger]

Originally Posted by softballnrd27

Clinebarger-
I am currently looking for a decent 4l80e to build up and I can only find the 91-96 cores in the price range I am comfortable with. It will be behind a 5.3 and will eventually have a turbo or 2. My current th350 wont hold fluid and is slipping real bad so I need to replace it. Can I control the 91-96s with the 03 computer?

A 91-93 can be modified to work with a '03 PCM. '94-'96 will work with no modifications.

I will cover the '91-'93 modification in detail because others might need this also....

'91-'93 models use a "Silver" Bosch EPC Solenoid that is not compatible with '94 & up PCM's, It was replaced with a "Black" EPC. It is an accepted method to just replace the EPC with a '94-'03 version, And most of the time it works fine, But in some cases it will cause line pressure issues, Besides if your rebuilding....Do it right from the Start!!!

Parts needed....
'94-'03 EPC solenoid
.093" drill bit
Trans-Go Separator Plate part# 48-PLT-01
IF your core has the original internal harness, You will need a '94-'03 Harness

First INDENTIFY your Valve Body! Parts get swapped all the time....
Notice the EPC is Black, This is a '01 Core.
Notice the Arrow pointing to a slot in the Valve Body, This is the EPC Vent. A '91-'93 will not be vented.







Once the Valve Body is removed, Flip it over, Remove the EPC, At the Arrow, Drill a .093" hole through too the other side, This will Vent the EPC with a hole instead of a machined slot.





I am including this for Information, '91-'93 will have a EPC hole in the Separator plate, This is no longer needed now that you Vented the Valve Body, The Trans Go plate does not have this hole, You have now completed your conversion to the Later/Better/Compatible EPC solenoid.
Picture of where the EPC hole is in the plate...

[clinebarger]

Originally Posted by softballnrd27

Can I add an aftermarket floor shifter later on down the road? I plan to do everything you have listed, can you explain why? Just for my knowledge, not questioning you at all.

Yes, You can add a Floor Shifter, However....With correct PCM Tuning, You do not need to manual shift this unit, Just remember to always Race/Burnout in D3 NOT D4/OD, Selecting D3 applies the Overruns & Protects the Overdrive Sprag from Shock/Damage.

I listed a lot of things that NOT EVERYONE will need, Do you have a max horsepower/torque goal? Slicks/drag radials?

[softballnrd27]

Probably drag radials and enough horsepower to run low 10s to high 9s. I'm not sure on the power level needed to reach those numbers. It will be a while before I add the turbo(s) so I am trying to get the overdrive for now and slowly accumulate all the needed upgrades like the billet shaft. A basic rebuild is all I am looking to do for now due to the $$$ and time schedule.
Will I need to do a segment swap to be able to control the 4l80e?