Re: 4L80E & TH400 Tech.
 

You will need a basic Seal Kit or Buy individual seals from GM.

For example....If you pull the Pump out to replace the Input Shaft, You will need the Pump to Case paper gasket & all 4 Sealing Rings on the Shaft itself.

If I were you....I would do the SpiroLock Intermediate Snap Ring & Billet Forward Hub now so you don't have to pull the Valve Body, O/D Housing Bolt, O/D Housing, Forward & Direct Drums to install the Snap Ring & Forward Hub.
These 2 items only add $200 to the build.

Then you just have to pull the Pump, & O/D Carrier/Overrun Housing to replace the Input Shaft later on (Don't even have to remove the Pan)

Re: 4L80E & TH400 Tech.
 

Chris,
Just wanted to thanks for all your help and info from this thread on my rebuild. Trans is done and ready to go back in the truck.
https://photos.smugmug.com/photos/i-...-9fzHV3k-L.jpg

Re: 4L80E & TH400 Tech.
 

Your welcome, Let us know how is shifts.

Re: 4L80E & TH400 Tech.
 

Chris

I have more of a programming question than a mechanical rebuild question for the 4l80e.

The set up is a 5.3 running off a 2000 Silverado PCM. We did a segment swap to change from a 4l60e to the 4l80e. Followed the wiring changes needed as found on LT1Swap.com.

The truck idles fine in park or neutral, but stumbles and dies when you put it in gear. From past experience with a TH350 doing this, it would lead me to believe the convertor is to tight and loading up the engine. Before going to that point and swapping convertors, we have some other thoughts/questions.

When we shift the trans to drive or reverse, the notice the O2 sensors nearly stop working and then it dies. If we add 1-2% throttle, we can keep it running.

How does the electronics of the trans interface with the PCM? Does shifting it to drive electronically effect some part of the tune for the engine? If so, what parts should I look at?


Thanks!

Re: 4L80E & TH400 Tech.
 

More like how it holds up to my abuse and the twin turbos :devil::devil:

Re: 4L80E & TH400 Tech.
 

There is a Park/Neutral wire that comes from the Neutral Safety Switch that idles the engine up 100rpm when you shift into any gear other than Park/Neutral, But most swaps dont need it.

Is you IAC motor working?, A stuck IAC will cause this issue because it cannot adjust for load.

Converter Clutch Drag is VERY common on high mileage 4L80E's because the lack of "Lube to Line" bypass on stock units, Is this a rebuilt unit? This usually rears its ugly head when the unit is Hot/At operating temp.

I'm not a Tuner, I wish I was!! Boosted C10, BrewCity, or Hart Rod will know more about that. I take that back....I don't wish I was, My plate is full enough

Pressure Rise, Pressure Rise, Pressure Rise:smoke:

Re: 4L80E & TH400 Tech.
 

Is there any advantage of using 6 over 5 disc direct drum? I know 6 will hold more lbs but is it worth the trouble. I'm using a 4L80E 34 sprag direct drum. I need to buy a aluminum piston the 2 sources I found said they could machine it to work with 6 disc or 5. It was my understanding that the 4L80E direct Drum has enough room for 6 disc if you remove the wavy and replace with steels.

Re: 4L80E & TH400 Tech.
 

Does your kit have the extra Friction & Steel?, If so....Have it machined for 6 Frictions. If not....Stay with 5 Frictions. And too add something myself.....I have GREAT luck using 5 Friction set-up's when using 4L80E High Energy Frictions!
There was a few TH400's that came Factory with 6 Frictions in the Direct Drum (Behind 500 Cadillac's mostly), The 4L80E drum is machined to the same depth.

Technically it has room for the Wave & 6 Frictions, Depending on the Machined Height of the Piston.
What you DO NOT want too do is use a late 4L80E wave plate with a Piston machined for 6 Frictions & a Wave Plate, The 4L80E Wave is super thin & can get logged under the "Lip" in the Drum & burn the Directs down, Break the Piston etc.
It is fine to run no Wave in the Directs......BUT, Along with Blocking the 3rd Accumulator, Can cause a overly harsh 3rd Apply.

More Direct Clutch/Drum info....
Sometimes, You can Omit the Wave, Stack the Directs with 6 Forward .077" Steels & 6 .080" Frictions with a 5-Friction Piston, It's a rare occurrence this stacks-up with the correct clearance (.010" per friction), Got to watch what you read on the internet....Just because it works on one Drum/Piston/Backing Plate combination, Does Not mean it will work for you!

As I touched on in our PM exchange....You NEED a Bleed Checkball in the Drum OR the Piston....But NOT both, Aluminum Pistons come in BOTH configurations! All 34 Element 4L80E Direct Drums have the Bleed in the Drum.
If you or others get a Piston with a Bleed Capsule.......It's a easy fix with a 1/4-28 Set-Screw.
Drill out the 2 tangs holding the Checkball in place, Remove the Checkball, Drill the hole all the way through with a 7/32" Drill Bit, Tap the hole with a 1/4-28 Tap.....NOT all the way trough!! You have to leave material for the Set-Screw too seat against, After you get the depth set right, Loctite the Set-Screw in & let sit overnight.

Aluminum Direct Piston with a Bleed Checkball, & the 1/4-28 Set-Screw.
http://i296.photobucket.com/albums/m...ps0zsvmbsm.jpg

The Same piston from the top, The deep spring pockets, The fact they can be machined, & They are very Stout are the reasons to use the Aluminum Direct Piston in any H/P TH400 or 4L80E build using High Rate return springs.
The Yellow circle is the Bleed, Between the 2 arrows is the material that gets machined for Piston/Clutch height.
http://i296.photobucket.com/albums/m...psb2vtqh1r.jpg

This is a Stamped Steel TH400 Direct Piston with a Insert too control height, DO NOT use this Piston, They work OK on stock builds, Put Pressure to them & they can & will Fail!
http://i296.photobucket.com/albums/m...psppbzohgb.jpg

4L80E Molded Stamped Steel Piston, Not suitable for High Rate Springs.
http://i296.photobucket.com/albums/m...pshcmeorwe.jpg

Re: 4L80E & TH400 Tech.
 

Would it be okay to run the heavy duty return springs with 5 clutch disk setup and all the modifications you describe in this thread? No reason for me to use anything from the transgo 400-pro kit I bought Ill just return it to summit. Thanks for posting the pictures some good information there.

Re: 4L80E & TH400 Tech.
 

Yes, You can use High Rate Return Springs no matter the Clutch count.

I'm not a big fan of the Trans Go 400-Pro anyway......Mostly because the Multi Layer Separator Plate. That's how they Dual Feed the Directs without trans tear down. The Overkill Pressure Regulator Spring bumps pressure too much at Idle/No load. If you need to downshift into 1st at high speeds....I can walk you through that modification.
But you will need to purchase the Return Springs, Boost Valve, & Intermediate Snap Ring separately.

Return Springs
http://www.ckperformance.com/View/HI...ELEASE-SPRINGS

Boost Valve
https://www.summitracing.com/parts/sox-400-lb1

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

If the budget allows, A Billet Direct Piston would be a nice addition & You can spec it out the way YOU want!
http://www.ckperformance.com/View/BI...-CLUTCH-PISTON

Re: 4L80E & TH400 Tech.
 

I would like to be able to manually shift down to 1st gear if possible. What do you think about this pressure regulator spring CK sells 185-190 PSI http://www.ckperformance.com/View/TH...GULATOR-SPRING Should I just leave the stock spring in the pump?

Re: 4L80E & TH400 Tech.
 

I'll snag a Valve Body from work & go through the mod with you, Just keep in mind it will shift into 1st at ANY speed!!

Higher Rate PR Springs boost pressure in a Linear fashion, The increase at full throttle/high load is fine, It's the increase at Idle/No load is the issue in a street vehicle with a sub 3000 stall converter as it will bang into gear. If your going too run a High Stall Converter......You won't feel it.

Large Ratio Boost Valves boost pressure in a Progressive fashion, Good pressures a full throttle with No increase at Idle/no load conditions.

**The Sonnax 400-LB1 does include a 10% stronger PR Spring, This is the increase in pressure at "No-Load/Torque Signal" in the Graph)**
I added the Red Line to reflect about what the CK PR spring will do.

http://i296.photobucket.com/albums/m...pspi2mcb9j.jpg

Re: 4L80E & TH400 Tech.
 

Reading another wiki on modifications it was suggested one use only half heavy duty return springs and half stock springs in the direct drum? Do you have any thoughts on that I see you already discussed a .30 bleed hole with 5500RPM and higher applications. My assumption is more pressure is needed in the direct drum to over come the heavy duty springs.

Re: 4L80E & TH400 Tech.
 

Did they mention a reason for Half High Rate & Half Stock return springs?

Because, I can't think of one..... I have ran full sets of high rate return springs in Stock Pressure TH400's with no issues, The springs will hold-off the Piston from moving 'til a little more pressure builds, Resulting in a later but Quicker shift. Buy later, I talking 100th's of a second.

With used stock spring, They could have millions of cycles on them, I testing several sets on my Valve Spring Checker, Set right before coil bind....The weights were all over the place, Springs from CK, ATI, & Hughes are very uniform in weight, Trans Go spring are OK but have the most variance in weight out of the aftermarket springs I tested.

You could use the Half & Half method & probably be OK as long as they are staggered (1 High Rate, 1 Stock, & so on)

Builders have their own practices & beliefs, Some of this stuff can not be proven in a conventional way, We do one mod, Test the trans, Tear it down 100-300 passes later & assess the situation.

The Bleed hole is a secondary guard from centrifugal apply at high RPM, & a faster release on "Detent" Downshift, & "Forced" Downshift.

Re: 4L80E & TH400 Tech.
 

I read about using half stock and half heavy duty from this he doesn't say whyhttp://www.crankshaftcoalition.com/w...0_rebuild_tech

I assumed the best way would be to alternate between springs ill just go with all heavy duty

Re: 4L80E & TH400 Tech.
 

I have, amongst other vehicles, an 07 Trailblazer LT, with the 5.3.

I'm swaping the 5.3 for a 6.0, and would like to swap a 4l80 behind it. If I used a 2WD for a donor, would the VSS on it be able to communicate with my PCM with a segment swap or repinning the harness?

Re: 4L80E & TH400 Tech.
 

Is this 2WD, 4WD, AWD??

Re: 4L80E & TH400 Tech.
 

4wd, I currently have an NP 226, I would be swapping to a 241, or 261 depending on what is easier.

Re: 4L80E & TH400 Tech.
 

Both NP241, NP261 have a VSS sensor, So no need for you to buy a 2wd unit. A 4wd unit & Adapter will fit both T-Cases.

We only use 2wd units when adapting a older T-case that doesn't have a Output VSS sensor.

All GM Output VSS sensors create the same 40 Pulses Per Revolution A/C Sine Wave Signal.

Re: 4L80E & TH400 Tech.
 

Perfect! That's what I needed to know, thank you.

Re: 4L80E & TH400 Tech.
 

Subed for reference.

Re: 4L80E & TH400 Tech.
 

Not sure if you covered this or not but what is the best way(right way) to convert from the bolt on yoke to a slip yoke on a 1998 4l80e? I ordered a a slip yoke that fits the trans but it doesn't seem like it allows enough slip.

Re: 4L80E & TH400 Tech.
 

I have not......

The easiest thing to do is run a short "Counter Bored" Yoke, http://www.sonnax.com/parts/3841-slip-yoke

The "Correct" way & a Must for vehicles with a lot of suspension travel is to machine off the O-ring boss & run a long full spline Yoke.

The "Best" thing to do.....Buy a Core with a Full Splined Output Shaft to start with.

http://i296.photobucket.com/albums/m...psyb4ula29.jpg

http://i296.photobucket.com/albums/m...psrxobaqd1.jpg

Re: 4L80E & TH400 Tech.
 

Clinebager, thanks for all your help on the forum here!

We've been going through 4L80E's like cookies at a bake sale on one of our trucks. Doesn't matter if they are rebuilt by Movarus, Good wrench , local shop or junkyard. I only am given a 90 day warranty on these as it's a snow plow(commercial) truck.
We have no check engine light, nothing shows up on the Verus, I have a pile of 2500 mi or less trans coolers and lines plus three new radiators installed to get any warranty. All of them have good line pressure when installed but in a few miles you notice it take longer to engauge first or reverse but still have clean fluid, another 500 mi or so you start to get soft shifts and some flaring between shifts, new fluid and filter and line pressure is 10-16 psi lower and soon the slipping in 1/2/r is very noticeable and we stop running it.
98 K2500 reg cab long box 5.7 powered truck.
We and dealer think it's an ecm/wiring Janessa problem, do you have any ideas?

Re: 4L80E & TH400 Tech.
 

I would like to tear one of them down to see exactly what's failing, Maybe I can walk you through it???

The change in line pressure has me concerned, Using a DVOM set to AMP scale, Connect one of the leads to the each of the Pressure Control Solenoid wires.

Pin 6 of the Clear connector is the PC High control
Pin 16 of the clear connector is the PC Low control

Use your scanner to monitor the Commanded Amp's......It should match the Actual output read by the DVOM. If it's off (Especially higher Amp's).....The PCM is faulty or You have a bad ground.

These transmissions may be eating pumps for some reason.....Like engine/trans alignment issues, Are both dowels present & in good shape??
Flexplate runout?
Inspect the pump gears, pump bushing, & pump body for wear/damage.

Check the Boost Valve Sleeve for being loose in the bore, The will cause Torque Signal oil to leak & cause low line pressure when the unit is hot.
Same with a loose Pressure Regulator Valve.

4L80E Reverse Bands are not suitable for plowing duty, Use a TH400 "Grooved" Band.

Check the Forward Drum for damage where the Input Shaft & seals ride, VERY commonly over-looked & will cause repeat Forward Clutch failure.

Use Raybestos grooved HD frictions in commercial applications (Forward, Intermediate, Directs)

Do not use 4 frictions in the Intermediate Clutch, Use 3 TH400 frictions, Wave Plate, Steels & Backing Plate. The 4 friction set-up is great for holding power BUT no so much for a HD set-up.

Set your end-play correctly!!!!! TH400/4L80E will beat themselves to death with to much end-play, Very quickly in a plow truck that is shifted from forward to reverse a million more times than a regular truck.
http://www.sonnax.com/articles/408-p...-train-failure

Re: 4L80E & TH400 Tech.
 

Thanks for the tips- I really appreciate them! Have made a copy to pass on to my new Trans guy for my 2002 GMC k2500 trans this summer. We don't rebuild our own due to time, either buy reman or send out.
Wish you had a shop here!
Thanks Again!

Re: 4L80E & TH400 Tech.
 

Thanks for the tips- I really appreciate them! Have made a copy to pass on to my new Trans guy for my 2002 GMC k2500 trans this summer. We don't rebuild our own due to time, either buy reman or send out.
Wish you had a shop here!
Thanks Again!

Re: 4L80E & TH400 Tech.
 

Awesome thread. Just awesome. I look forward to using it when I rebuild my old 93 4l80e.

Thanks clinebarger for the effort you put into this!

Re: 4L80E & TH400 Tech.
 

You probably covered this somewhere in here but I'll ask again.
I just put a 4L80 from a 2002 van behind a gen 1 327.
the van had a 350 vortex in it. fluid was good so I just put a filter and fluid in and crossed my fingers.
Everything worked good when I fired her up. upshifts and downshifts in drive all good. Then when the controller ( Quickshift 1) shows 140 F. the convertor starts locken up and killen the engine. worse in reverse but still bad in fward.
I put a temp gauge in the test hole on drivers side of tranny. the gauge takes 30 minutes to come up to 100 F. but the controller says I'm at 140 F. I checked the gauge and sending unit on my engine temp system they are working. The tranny is plumbed into the rad. but did have a little trouble getten the lines in close enough to the tranny so they don't hit the tunnel.
I don't have any trouble at 130 F. but then it starts grabbing real hard above that. this is my first electric lock up tranny, but I've rebuilt some TH. in the past. ???

Re: 4L80E & TH400 Tech.
 

The Cooler Circuit is routed to the Converter first to keep the TCC Off & Charge the Converter.
If this circuit does not have the correct volume, The TCC will drag and/or lock-up & kill the engine.

This is caused buy 1 of 2 things.....

1. Worn out pump, PR Valve Bore, or End Plug leak..... As the fluid heats up, Pressure & Volume drop, The Pressure Regulator Valve will put a priority over the Cooler Circuit to maintain Line Pressure, The symptoms will happen at idle because that's when the pump is least efficient.

2. EPC "amps" to low at idle, (To much pressure demand), Amps should hover right around 1.00 at idle. Have you "Learned" the TPS value on the controller?? The controller must know where closed throttle/idle is!

To low of a curb idle can also cause this.

Re: 4L80E & TH400 Tech.
 

I did set the TPS up it's a pretty nice holley product designd for the electric choke on the carb. low idle shows .54 volts h. idle is 4.40. I'm not sure how to check the amps. I,m pretty sure I can turn the voltage up if that's what your talkin about. Does the fact that I don't get good temp readings at the test outlet mean anything

Re: 4L80E & TH400 Tech.
 

So I'm doin some more homework.
seems like if the pump and or
pr valve was weak or to many bleed of spots that increasing pressure with RPMs would bring the convertor out of lock up. But if the EPC sol. is screwed up or the cooler line is restricted that the thinner the fluid get the quicker the PR valve will lock up the convertor. Am I thinkin in the right direction ? I don't like replacen parts till I understand why I'm replacen them.

Re: 4L80E & TH400 Tech.
 

Hey clinebarger

As I posted the other day I got ahold of a cheap '93 4l80e that was taken in as a supposedly working core. (I bought it from a retired trans builder that had it left laying around) Even though it supposedly works, I am going to assume it needs a rebuild to be "right."

I am going to use this in a turbo LS swapped C10. It will have a max of about 800hp but more realistically around 4-500 horsepower for street cruising.

I know the 800hp is pushing it pretty hard on the input shaft and forward clutch hub. I also know this trans still has the old outdated harness and case connector so it likely has never been opened up. Sounds like the 93 is good that it has the larger overdrive roller clutch but bad that it also has a 16 element intermediate sprag.

So it sounds like I need to upgrade the wiring harness and the intermediate sprag for sure. Probably the input shaft and forward hub also? Who do you go to for good rebuild kits? I have been looking at the rebuild kits from Jake's Performance either stage 2 or stage 3.

http://www.jakesperformance.com/rebuild-kits/

The price seems fairy steep but maybe not too bad once you add up all the little things this trans probably needs anyways to be brought up to spec. What do you suggest?

Re: 4L80E & TH400 Tech.
 

I should add I have never rebuilt a transmission before but I'm a machinist for a day job so I am familiar with all of the various measuring tools and how to use them. Sounds like that is a lot of the job.

Also, I haven't even taken the pan off to check the magnet or get a general status check on this transmission. I do know it had fluid in it when I picked it up and it was red and not burned smelling.

Re: 4L80E & TH400 Tech.
 

More reading on the subject, http://www.sonnax.com/articles/124-a...-lube-circuits

Re: 4L80E & TH400 Tech.
 

Yep, I've read it twice and see your posts on the LS1 site that tells how to run some tests. It's slowly making sense. I'll get it. thanks for advice.

Re: 4L80E & TH400 Tech.
 

Before you order anything, I made a typo in my original post, Early (Pre '97) 4L80E's have a Intermediate Roller Clutch, Not a Sprag.

It would be in your best interest to buy a compete 34 Element Direct Drum.

Drum, http://www.ckperformance.com/View/6-...L-RETAING-RING

Calibration kit, Accumulator delete, PR Spring, Intermediate Snap Ring, Hi-Rate direct springs, Machined TH400 Direct Piston, Parts to rollerize the Case, & Instuctions.

Forward Hub, http://www.ckperformance.com/View/FO...ZED-CLUTCH-HUB

Input Shaft, http://www.ckperformance.com/View/CO...ON-INPUT-SHAFT

Coated Pump Gears, http://www.ckperformance.com/View/4L...D-PUMP-GEARSET

Sonnax Boost Valve, http://www.sonnax.com/parts/2170-lin...re-booster-kit USE THE CK PR SPRING!!!

Sonnax PR Valve, http://www.sonnax.com/parts/1989-lub...egulator-valve

Sonnax shims to set Carrier end play, http://www.sonnax.com/parts/1979-shim

Bearing kit, http://www.sonnax.com/parts/3021-bearing-kit

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

I like to use a TH400 Rear Band, Front Band RARELY need replacement!
Local Trans Supplier.

Seal Kit, Local Trans Supplier.

Steel Plate kit, Local Trans Supplier.

Borg Warner Fiction Module, Local Trans Supplier. Here is a picture of the Module & part number.
http://i296.photobucket.com/albums/m...psvmzc4pl6.jpg

Re: 4L80E & TH400 Tech.
 

Nothing against Jake, But his kits are based on the assumption that you already have a 34 element "Sprag" style direct drum.

Front Band, See above.

Lo-Roller Clutch, If no metal is embedded in the "Dogs" & it's in good shape.....Not needed. Your will have "No Legs"/Early style if need to know.

Solenoids & Harness, Source these from a GM dealer for a 2001 C2500, And do the EPC mod I detailed in this thread.

Bushing kit, Local Trans Supplier, (I forgot)

Re: 4L80E & TH400 Tech.
 

Can I get a ID on this trans, guessing 2002 2500hd.

Re: 4L80E & TH400 Tech.
 

2005