For the THM400, there are two different stock bushings... both have oil grooves.

A wide bushing with grooves and a hole:









And a narrow bushing with grooves only:



If there are any other bushings that can be used in this location, I am not aware of it.
The 4L80E generally ONLY will fit the narrow bushing.

 

This bushing works nicely... I am glad that you turned me on to it.
For any of you that have not used this bushing, it is approx. 1/8" wider than the THM400 case bushing...
The original 4L80E case bushing is very small in comparison.

 

Lol

I know... I said: "This causes issues with shifting and insufficient Boost/ Line-Pressure rise", in that post.

 

Here are some images showing differences between the EARLY-4L80E and the LATE-4L80E.
There are many more changes than what is shown here... I do NOT have images for everything at this time.
Most of these are images from TransGo:



This images above shows the Cooler-Return port locations of both the EARLY and LATE designs.
The EARLY design has both ports at the Pump assembly.
The LATE design has the Return port moved to the Center-Support.

The image below, shows how the splines of some components were changed to better allow Lube-Oil to pass through the Transmission:




For example; the splines of the Ring-Gear for the Rear-Planet, look like this so that Lube-Oil can pass down to lubricate the Output-Shaft bushing
Output-Shaft bushing shown again below:





The Change in the Center-Support and bushing, for the Cooler-Return port are shown below:



Below is an image out the Output-Shaft change, where the lube holes for the Case-Bushing were removed:




Here is a HyperLink to the TransGo article that has these images: TransGo 4L80E Changes

 

Next are hydraulic diagrams, comparing EARLY and LATE design Lube-Circuits.

This image shows the passages of the Pump flange/ Case for the EARLY design.
The different circuits of the transmission have different names and numbers...
#13 is the Cooler-Return Fluid/ Circuit (Lube-Oil).
This images shows Cooler-Return Fluid entering the Transmission at the Pump via:
-the Transmission Cooler Return Fitting next to the Pump (Left circle).
-the Cooler Return Port in the Pump Flange (Right circle).




This is the same image for the LATE design.
The Transmission Cooler Return Fitting is no longer next to the Pump, It has been moved next to the Center-Support.
The Cooler Return Port has been removed from the Pump Flange.




The next images are hydraulic diagrams, showing the Lube-Circuit entering the transmission and where it goes.
In the EARLY design, the Lube-Circuit separates into two sections (Front section Lube and Rear section Lube).
As Lube-Oil enters the case near the Pump, the Lube-Circuit divides...
One section goes through the Pump, becomes the Front section Lube; exits at the Rear of the Stator-Support to bring Lube-Oil to the OverRun and OverDrive components.
The other section goes down to the front of the Valve-Body, then enters a long Lube-Pipe that goes into the Case Bushing Journal...
The Case Bushing and Tail-Shaft Bushing receive Lube-Oil; then Lube-Oil enters the Output-Shaft, enters the Main-Shaft, and Lubricates all of the components through the Forward Clutch.
Below is an image of the Early design showing both sections being created...




The Rear section from here will enter the Valve-Body as the #13 Fluid and then enter the Lube-Pipe.
Case passages image below:




Next is the LATE design, where Lube-Oil does not enter the Case near the Pump... But enters into the Center-Support.
The Lube-Oil here does not separate into other sections... It becomes the Center section by itself.
The other two sections (Front and Rear) do not come from here, and instead originate from other locations/ circuits.
Below is an image of the Pump and the Cooler-Return Fitting that is in the Center-Support; becoming Center Lube-Oil:




In the LATE design, the section of the Valve-Body that had the #13 Fluid... is no longer present; it is a void in the LATE design.
The Cooler-Return Fitting is also shown to be moved rearward to the Center-Support. Shown below:

 

The Late design has 3 section for the Lube-Circuit.
The Center section was just gone over, and the other 2 sections will be covered next.

These 2 other sections of the Lube-Circuit, DO NOT receive cooled oil from the ATF cooler return line.
In the Late design Lube-System... ONLY the center section Lube-Circuit receives cooled ATF.
The Early design Lube-System, has only 2 sections... and BOTH receive cooled ATF.

The Front section still Lubricates the OverRun and OverDrive components...
But the Lube-Oil actually comes from another circuit in the Pump, that serves another purpose (and is not cooled oil).
The Regulated Torque-Converter Feed Circuit is used for the Front section of the Lube-Circuit.
This circuit is very important; is used for Torque-Converter Clutch, and would be better off undisturbed...
However the Front Section of Lube-Oil is stealing oil from this circuit.

Below are some images of the Pump showing where the Front section of Lube-Oil starts.

The image below shows a hydraulic diagram of the Pump with the #24 orifice in the Blue circle, which is the start of the Front section of Lube-Oil (Fluid #49 being stolen from Fluid #8).




The image below shows the same information as above, but of the physical passages/ chambers of the Pump:





Here are the same diagrams, but of the Early design...
Regulated Converter Feed is undisturbed... Hydraulic diagram below:



...and now the physical passages and chambers of the Pump below:

 

I'm late to the party but this is excellent! Thanks for this Chello!

 

Next is the Rear section of the LATE design Lube-Circuit.
Just as the Front section of the Lube-Circuit is taken from another circuit with a different purpose...
So is the Rear section of the LATE design.

The Rear section comes from the Actuator Feed Limit Circuit (and again is not cooled oil).
The Valve-Train for this circuit is often worn as we discussed earlier in this Thread.
Not a good idea to steal fluid from it to create the Rear section of the Lube-Circuit.

Below is the hydraulic diagram of the Valve-Body; showing the AFL circuit section that starts the Rear Lube-Oil section:




And next, the image below shows the same information, but of the physical passages of the Valve-Body:

 

The Three final parts of this Thread will be regarding 4L80E Lube-Circuit Modifications.

The First part will be Lube-Circuit Modifications that apply to both the EARLY and LATE versions.
The Second part will be Lube-Circuit Modifications for the LATE version ONLY.

Last, the Third part will be some Modifications that I have experimented with regarding the first iteration of the LATE Lube-Circuit...
This is mainly because the Pump-Flange of the case still partially retains the case passage that was present in the EARLY design Cooler-Return Fluid.
This part will be discussing my experiments with bringing Cooler-Return Fluid into the OverRun and OverDrive sections (like the EARLY design did, but with a replacement Pump that can be used for either EARLY or LATE units).

 

I am looking for some more images of the 4L80E assembly process...
If anyone has any readily available; Please contact me and I will sent my E-Mail address to receive the images.

Specifically, if anyone has any images of the LATE design Center-Support Bushing installed into the EARLY Center-Support...
That would be very helpful and much appreciated.

Thank you!

 

I did see that a few of the members here, were interested in this topic...
Please do ask any questions that any of you have on this topic.

To Be Continued soon, depending on any images that I receive.

 

you must not have gotten my image?!

 

No, I could not find it. Sorry.

 

excellent stuff Sir! thank you for sharing your knowledge.

 

Thank you Doug!

Good chatting with you the other day.

 

So Maroon Monster has been working on getting some images sent over to me... I know that he is busy though.

Doug, if you have any build images that you could send me that would be great!
If you can do so... send me another PM and I will replay with my E-Mail address.

Of course anyone else that would like to help is welcome to as my Photo back-up Server hard-drive array is rebuilding itself after a disc failure.

 

roger that. i'll pm you now. I'm putting together a '98 tomorrow.

 

Okay...
Trying to find the time to continue this.

I did get Bushing/ Center-Support images from Maroon Monster. Thank you Grady!
I also got an E-Mail from TruckDoug for a Link to a 4L80E 2.75:1 Gear set??? Thanks for trying Doug.

Starting off with the Lube-Circuit again... well not technically, but Converter circuits that can become Lube-Oil.

Some of the most important parts for the Lube-Circuit, are the Front Bushing of the Stator-Support Tube...
and the Pump to Torque-Converter Bushing.
Both of these bushings also need to act in part as seals to separate hydraulic circuits from one another.
So Bushing fitment and clearance for both of these bushings are critical.

Here is a Sonnax extra-Wide Front Bushing for the Stator-Support Tube:



Sonnax part # 34016-Wwill help seal this area between the Input-Shaft and the Stator-Support Tube.

The Late (1997+) units use a wider Pump Bushing than the Early units.
The Late Bushing should measure 0.675" or 0.700" wide.
Where the Early Bushing should measure ONLY 0.550" wide.

I recommend fitting the wider Bushing in all model years...
Just be cautious with the Early units, of the Bushing position/ placement...
as it can interfere with the Pump or the Pump to the Torque-Converter Seal.

I have become very happy with Dura-Bond "Coated" Bushings in the last few years (especially for the Late 4L80E units).
Here is an image of a wide Pump Bushing from Dura-Bond with a PTFE like coating:




Here is an image of a full set of these "coated" Bushings from Dura-Bond for the 4L80E (Late set in this image):





On the Topic of Bushings...
The Late 4L80E STOCK Lube-Circuit is heavily dependent upon Bushings.
We will be discussing modifying the Late design, in order to be less dependent upon these Bushings.
In particular... I am discussing here the Center-Support Bushing, and the Sun-Gear Shaft Bushings.

The Late design uses different Bushings in these locations than the Early design.
As discussed much earlier... The Late design uses a Solid Intermediate-Shaft...
Lube-Oil flows Between the Intermediate-Shaft and the Sun-Gear Shaft... due to Oil-Grooved Bushings in the Sun-Gear Shaft.
These Bushings look like this (which we looked at way earlier on also):








A Lube-Circuit modification for the Early units, would be using the Late design Oil-Grooved Bushings in the Sun-Gear Shaft...
and using the Late design Center-Support Bushing.

The Late design Center-Support Bushing is Taller/ Longer than the Early design.
Using the Late design Bushing in an Early unit creates two benefits.
One: it better supports the Sun-Gear Shaft.
Two: it better directs Lube-Oil to the Bushing inside of the Front Planet/ Reaction Carrier... and to the inside race for the One-Way Low Roller-Clutch.

Here are images from Maroon Monster that display the Taller Bushing and Oil Grooving/ Channeling to the passage that Lubes the Bushing of the Front Planet/ Reaction Carrier... and to the inside race for the One-Way Low Roller-Clutch:


The image ABOVE, shows Grady pointing to the Lube-Passage that goes to the Bushing of the Front Planet/ Reaction Carrier... and to the inside race for the One-Way Low Roller-Clutch.
While the Passage is in both the Early and Late design Center-Support...
Only the Late design Bushing is Tall enough to reach this far down in the Center-Support...
With Oil-Grooves and an Oil-Passage in the Bushing to bring Lube-Oil directly to the Passage for the Bushing of the Front Planet/ Reaction Carrier... and to the inside race for the One-Way Low Roller-Clutch.

Below, Grady is showing the same Passage, but from farther away...
Better showing the upside-down Center-Support...
and where Lube-Oil exits to the Bushing of the Front Planet/ Reaction Carrier... and to the inside race for the One-Way Low Roller-Clutch.

 

Many Lube-Oil modifications are minor, especially concerning units behind stock or low power engines.
Other Lube-Oil modifications are significant regardless of engine power.

One of the less important Lube-Oil mods (Unless Power is getting high and Improved clutch cooling should be used from anywhere available)...
is adding/ increasing the holes/ Lube passages of the Forward Clutch-Hub and the Forward Clutch Backing-Plate/ Direct Clutch-Hub.

It is difficult to see... but the Forward-Hub to the right has had more Lube Holes added in the image below.
Adding 2 or 3 Lube Holes (0.187" to 0.250") to the approximately 45-Degree Face above the Splined area for the clutch teeth...
bringing Lube-Oil from the Forward-Clutch into the Direct-Clutch (a more important Mod. for a THM400).


Also shown is an increase in the number of Lube-Holes in the splined area for the clutch teeth.
Try to increase the Lube Hole count by 33-Percent.

Also the diameter of the Lube Holes can be increased to the Full width of the groove intended for a clutch tooth.
Mainly THM400 would need this done as apposed to 4L80E Transmissions.

The image below shows the same modification done to the Forward-Clutch Backing-Plate/ Direct-Clutch Hub on the Right side:



This image above, makes the increased number of Lube-Holes easier to see/ count.

Changing the subject again...
When discussing the 4L80E Pump and Bushings; I forgot the most important part of what I was trying to say.
I apologize for jumping around again.

I consider this a more significant Lube Modification!
This is something that I consider to be Mandatory for any 4L80E with Fixed High Line-pressure or a Trans-Brake.
Very briefly I wish to mention a design improvement that GM/ Hydra-Matic Engineers made to the Late design THM400 Pump.
I mention this, because the modification I will show next... comes from a STOCK improvement that GM created for the THM400.

Here is an image of the Late design THM400 Front half (Casting number ending in: 895) of the Pump:



The Blue Circle on the image above shows a small gap between the Outer Pump-Gear and the Pump Casting.
This small gap is referred to as a "Pocket" and it is for Oil to collect and help prevent excessive Pump Gear wear and tear.
I am not going to discuss the how/ why this works until later.

Both the Early design THM400 Pumps and all of the 4L80E Pumps lack this "Pocket" that is shown in the Blue Circle.
So, we modify the 4L80E Pumps (and Early THM400 Pumps) to have this pocket made via a simple milling process.
Thanks to Maroon Monster again for the next image that follows.

The next image shows the same pocket, but with the Pump Gears removed.
Shown below inside the Red square:


This Modification should be performed on all 4L80E units that have Fixed Line-Pressure or a Trans-Brake.

 

I am not sure that I am going to bother to finish this...
It has been a lot of work, late at night after days and days full of a lot of work at my business...
I don't think this is worth it to the forum members; other than maybe 10 of you.
Sorry.

Thank you to MaroonMonster, TruckDoug, and everyone else who contributed in helping me with photos.
You guys are all awesome.