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#1 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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4L80E & TH400 Tech.
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. |
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#2 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
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. |
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#3 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Omit the lip seal in the direct drum & the second sealing ring on the Center support.
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#4 | |
Registered User
Join Date: Aug 2016
Location: Lake Forest, CA
Posts: 2,177
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Re: 4L80E & TH400 Tech.
Quote:
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.
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"Work hard, use your vacation days." 1970 C15 GMC Long Bed 1986 C20 Scottsdale 1983 K2500 Sierra Classic Suburban 6.2 Instagram: C10sofOC Last edited by demian5; 02-09-2017 at 07:20 PM. |
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#5 | ||
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
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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. |
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#6 | |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Quote:
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. |
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#7 |
Registered User
Join Date: Aug 2011
Location: Yellowknife, NWT
Posts: 39
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Re: 4L80E & TH400 Tech.
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. |
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#8 |
1965 Chevy C10, 2005 4.8L/4l60
![]() Join Date: Aug 2004
Location: DFW Texas
Posts: 8,543
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Re: 4L80E & TH400 Tech.
Thanks Cline!
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Clyde65 Rebuild of Clyde http://67-72chevytrucks.com/vboard/s...84#post8338184 69 Aristocrat Lo Liner build http://67-72chevytrucks.com/vboard/s...84#post7561684 ![]() ![]() ![]() support our troops! |
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#9 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
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. |
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#10 |
Registered User
Join Date: Apr 2012
Location: Vegas
Posts: 617
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Re: 4L80E & TH400 Tech.
Thanks Cline! I'm getting ready to swap in an 86 TH400 and this is just what I needed
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#11 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
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#12 |
Registered User
Join Date: Apr 2012
Location: Vegas
Posts: 617
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Re: 4L80E & TH400 Tech.
Cost really, I'm getting the TH400/NP205 combo for less than the price it would be for a 4l80E/NP205 Adapter.
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#13 | |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Quote:
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! |
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#14 |
Registered User
Join Date: Apr 2012
Location: Vegas
Posts: 617
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Re: 4L80E & TH400 Tech.
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.
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#15 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
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. |
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#16 |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
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" |
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#17 | ||
Registered User
Join Date: Apr 2017
Location: Ventura County CA
Posts: 4
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Re: 4L80E & TH400 Tech.
clinebarger, thank you for the great tech advice!
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Last edited by -TheBandit-; 04-12-2017 at 01:03 PM. |
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#18 | |
Registered User
Join Date: Sep 2013
Location: Vacaville CA
Posts: 490
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Re: 4L80E & TH400 Tech.
Quote:
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#19 | |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Quote:
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. ![]() |
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#20 |
6>8 Plugless........
![]() Join Date: Sep 2007
Location: Prairie City, Ia
Posts: 17,140
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Re: 4L80E & TH400 Tech.
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.
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Ryan 1972 Chevy Longhorn K30 Cheyenne Super, 359 Inline 6 cylinder, Auto Trans, Tilt, Diesel Tach/Vach, Buckets, Rare Rear 4-link and air ride option Build Thread 1972 GMC Sierra Grande Longhorn 4x4 1972 Chevy Cheyenne Super K20 Long Step side tilt, tach, tow hooks, AC, 350 4 speed 1972 C10 Suburban Custom Deluxe 1969 Chevy milk truck 1971 Camaro RS 5.3 BTR STG3 Cam Super T10 1940 Ford 354 Hemi 46RH Ford 9" on air ride huge project Tired of spark plugs? Check this out. |
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#21 | |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Quote:
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! |
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#22 |
Always a work in progress
Join Date: Jun 2007
Location: Harker Heights, TX
Posts: 1,599
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Re: 4L80E & TH400 Tech.
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.
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USMC Retired Never trust a man who can't laugh at his own fart! 2010 Silverado Crew Cab 73 SWB 5.3/4l80e Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=695168 |
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#23 | |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Quote:
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... ![]() |
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#24 | |
Senior Member
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
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Re: 4L80E & TH400 Tech.
Quote:
I listed a lot of things that NOT EVERYONE will need, Do you have a max horsepower/torque goal? Slicks/drag radials? |
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#25 |
Always a work in progress
Join Date: Jun 2007
Location: Harker Heights, TX
Posts: 1,599
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Re: 4L80E & TH400 Tech.
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?
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USMC Retired Never trust a man who can't laugh at his own fart! 2010 Silverado Crew Cab 73 SWB 5.3/4l80e Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=695168 |
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