4L80E & TH400 Tech.

[Dustytrix]

Subed for reference.

[softballnrd27]

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.

[clinebarger]

Originally Posted by softballnrd27

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.

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.

[rickpilgrim]

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?

[clinebarger]

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

[rickpilgrim]

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!

[rickpilgrim]

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!

[indymachinist]

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!

[frankslagoon]

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. ???

[clinebarger]

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.

[frankslagoon]

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

[frankslagoon]

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.

[indymachinist]

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?

[indymachinist]

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.

[clinebarger]

Originally Posted by frankslagoon

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.

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

[frankslagoon]

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.

[clinebarger]

Originally Posted by indymachinist

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?

Originally Posted by indymachinist

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.

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.

[clinebarger]

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)

[dfarr67]

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

[clinebarger]

2005

[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.

[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?

[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.