4l80e Rear case bushing

[shootracing22]

Short Question:
Is the rear case lube circuit on a late model 97-2003 4l80e sufficient for rollerizing the rear case thrust washer with a TH350 bushing?

Early models a lubed through the shaft late models are lubed through the case. Being that this is a 4wd unit the tail shaft bushing or-face is blocked adding little more volume to the rear case thrust bearing and output shaft bushing.

Plus I am thinking that the rear bushing that centers the case thrust bearing needs some type of path for the oil to migrate to the rear case thurst roller. I have seen this mod made and some discussion on lube circuit but clear direction what is the best practice for the late model 4l80e.


Long story for anyone interested:
I have a 1989 v3500 Chevy 4x4 square body crew cab that I swapped in a 12 valve Cummins and a stock 4l80e that was pulled from a low mileage 2003 box van. The Cummins is currently making in the neighbor hood of 400hp and 1100ft lbs of torque at a very low RPM (max torque is usually made in the 2000rpm range). I am using a TCI EZ TCU by Fast to control it.

I haven't pulled it apart yet and needless to say the stock transmission did not last. Under full throttle 1st gear pulled strong, 2nd felt like it slipped, the converter lock up was not as firm as it once was and with the converter locked the truck didn't set you back like it once did. Now its not making any line pressure after idling in the yard I want to attempt to build if right this time around. I plan to go with a tripple disk converter tuned and built for the Cummins powerband.

My main goal is dependability with crisp shifts with out being to harsh since this is often used for the occasional under 10k light towing daily driver often ran in Over drive, and I am hoping the 4l80e is capable of this.

I recently ordered a Stage 5 kit from Jakes Performance with a valve body re-calibration kit that blocks off the accumulators. I plan on using the ATRA manual for most of the rebuild.

If my 2003 4l80e is stock rear case lube accumulator feed that lubes the rear case bushing isnt sufficient I read some builders find it necessary to block the accumulator feed lube tube and run a early intermediate shaft and out put shaft? Just want to make 100% sure this is correct before I go through the trouble

My plans are to run the Sonnax Smart-Tech Overrun Clutch Valve Kit Part No. 34200-40K. Running this kit will help with my late model overrun clutch will hold up or would it be wise to swap it to a early model larger overrun clutch? I have heard about one high HP application that it did well using this Sonnex kit did well in one of Jakes builds.

Any addtional parts or tips would you recommend for my build that is not included in the kit?

In advance I greatly appreciate any help. Like most people I am on a budget, my trucks is more of a hobbie I enjoy tinkering with but want to build it right. I built a few transmissions in the past and feel confident I can build this one by being thorough and paying close attention to detail.

I found this article though it dosnt address the lube circuit question it does address causes for thurst bearing failures due to load. I am going to try to apply this article to my build.

http://www.gearsmagazine.com/magazin...4l80-rebuilds/

Heres a picture since most of us like pics

[shootracing22]

Having trouble attaching pictures

[YoungPup1977]

I suggest you read thru the thread named TH400 and 4L80E tech, it has a few tips on how you can upgrade your 4L80E.....my experience here on this forum most people use "good used" 4L80's or buy from the internet...
No rebuilders on this forum, I will be real surprised if you get any replies on your requests...Good Luck.

[shootracing22]

Originally Posted by YoungPup1977

I suggest you read thru the thread named TH400 and 4L80E tech, it has a few tips on how you can upgrade your 4L80E.....my experience here on this forum most people use "good used" 4L80's or buy from the internet...
No rebuilders on this forum, I will be real surprised if you get any replies on your requests...Good Luck.

Thanks YoungPup1977 I been through it a few times. It's been helpful and I'll print out the sections I need to have them handy during my build. Plus keep searching I think I seen a few guys using rear case bushings with notches to allow lubrication of the rollerized case section. Also I found a excellent article addressing Thurst issues and carrier float on the 4l80e and th400 in gear magazine but it requires a whole lot of attention to detail and some machine work. Hopefully I can find some one that can help with the machine work part locally.

[Captainfab]

I thought you were an experienced transmission builder?

Originally Posted by YoungPup1977

I suggest you read thru the thread named TH400 and 4L80E tech, it has a few tips on how you can upgrade your 4L80E.....my experience here on this forum most people use "good used" 4L80's or buy from the internet...
No rebuilders on this forum, I will be real surprised if you get any replies on your requests...Good Luck.

[shootracing22]

He addresses rollerizing the rear case on the last page which answers my question. Lol... I read the first 4 to 5 several times thinking the last page wasnt useful. Thanks YoungPup1977. The late model lube system is sufficient in his opinion just need to carefully replace the AFL filter in the valve body during the rebuild and modify the Sonnex cure case bushing to not block the oil path.

[YoungPup1977]

Originally Posted by Captainfab

I thought you were an experienced transmission builder?

Whats your point....

[Captainfab]

Any other time you seem to be willing to help members with their transmission problems but now all of a sudden there aren't any rebuilders on this forum.......smh

Originally Posted by YoungPup1977

Whats your point....

[YoungPup1977]

Hey captain adapter man Did shootracing find his answer to his question ? I think he did. And I didn’t have to explain anything and reinvent the wheel...... referred him to a existing thread. Shame on me. What is untrue about my statement on “No builders”. Do you think I was speaking about you or myself. Someone must of took it personal. Lol!!!!!

Now you are policing how people answer questions. LOL !!!!!! You must be getting paid well to keep up with the way I reply to people on YOUR forum. Unbelievable !!!!!!!!
Posted via Mobile Device

[95 S_Trucker]

Originally Posted by YoungPup1977

Hey captain adapter man Did shootracing find his answer to his question ? I think he did. And I didn’t have to explain anything and reinvent the wheel...... referred him to a existing thread. Shame on me. What is untrue about my statement on “No builders”. Do you think I was speaking about you or myself. Someone must of took it personal. Lol!!!!!

Now you are policing how people answer questions. LOL !!!!!! You must be getting paid well to keep up with the way I reply to people on YOUR forum. Unbelievable !!!!!!!!
Posted via Mobile Device

Let's calm down a little bit. Captain fab is one of the most knowledgeable and nicest people on this forum. I can honestly say he would still be here if he wasn't a vendor.

You stated that you were an experienced transmission builder, and then you stated there aren't any transmission builders on this forum.

We are just trying to understand what you are saying. You are lying or contradicting yourself.

[YoungPup1977]

I don’t think I was referring to myself in that statement. Posted via Mobile Device

[61K10]

Where's the dog pound lol!

[old Rusty C10]

play nice guys

[61K10]

sorry-just my humor. No disrespect to youngpup.

[70cst]

Originally Posted by YoungPup1977

I don’t think I was referring to myself in that statement. I don’t give a damn about who your buddy is. Policing on how I answer questions What a joke to say the least. Calm down ? I am not the one offended. What’s the address to send the baby powder ?? That most likely will calm the rash
Posted via Mobile Device

Lets cool down ...

[YoungPup1977]

Originally Posted by 70cst

Lets cool down ...

I think the focus needs to be on if shootracing got the answer he was looking for and if he needs additional assistance instead of someone asking me if I am an experienced trans builder or not ...........
Posted via Mobile Device

[shootracing22]

Thanks again Youngpup1977! I tore into my 4l80e today and found more surpizes that will start a new thread to see if anyone has and idea of what caused it.

[Kawabuggy]

I have not looked through the "4L80E/400" build thread that was referenced above, but I am a transmission builder/rebuilder by trade.

One thing we do for the rear case bushing is to use a C6 pump bushing in that position. It is significantly wider than the factory case bushing and as such has less chance of walking, or spinning, in the case bore. There is no mod necessary to the bushing as it gets plenty of lube. This, of course, is on the 1997 & later cases that lube through the center support, and NOT through the output shaft as the earlier units do. I can attest to thousands of units running this way with no issues related to this mod. This mod DOES NOT replace the necessity of rollerizing the gear train though. It simply adds a little more support for the weight of the gear train and is significantly less likely to walk or spin due to additional contact with the case bore. We also use a very slight amount of Red Loc-Tite in the bore before installing the bushing. Absolutely critical that you get the bushing in perfectly straight. Any tilt, or angle, on the bushing and you will not be able to drop the lower assembly into the case.

[shootracing22]

Originally Posted by Kawabuggy

I have not looked through the "4L80E/400" build thread that was referenced above, but I am a transmission builder/rebuilder by trade.

One thing we do for the rear case bushing is to use a C6 pump bushing in that position. It is significantly wider than the factory case bushing and as such has less chance of walking, or spinning, in the case bore. There is no mod necessary to the bushing as it gets plenty of lube. This, of course, is on the 1997 & later cases that lube through the center support, and NOT through the output shaft as the earlier units do. I can attest to thousands of units running this way with no issues related to this mod. This mod DOES NOT replace the necessity of rollerizing the gear train though. It simply adds a little more support for the weight of the gear train and is significantly less likely to walk or spin due to additional contact with the case bore. We also use a very slight amount of Red Loc-Tite in the bore before installing the bushing. Absolutely critical that you get the bushing in perfectly straight. Any tilt, or angle, on the bushing and you will not be able to drop the lower assembly into the case.

Thanks for the feedback Kawabuggy!
Do you have any suggestions for a bushing driver kit for me to purchase for my 4l80e?
On a Google search I found a article written by Chris with CK performance in Gear Magazine about using a Th350 pump bearing between the rear 2 planetarys and milling the center support for a pump bearing to separate the thrust loads from the front and rear. Also correct carrier float on the direct drum and reaction planetary. Looks like a good mod just concerned about the added center support thrust getting proper lubrication.

[Kawabuggy]

Rollerizing the gear train is a great way to prolong the life of the unit in high performance applications, or where towing regularly, or when towing heavy loads frequently. IMO, it is not needed for 95% of most daily driven vehicles that rarely see abuse. We do it at my shop on Stage 3 and above units. It is typically a LOT of work machining everything, and assembling to check clearances as you go. We use a lathe, and a mill, for this type of work.

Lately, I've gotten to the point where we leave everything under the center support alone, and just rollerize everything between the pump, and the center support, and make certain that NO LOAD from the front of the unit is being applied to anything under the center support. This means the forward drum, O/D planetary set, and direct drum are floated on bearings and supported OFF of the sun gear tube, and the intermediate shaft. Essentially we are floating the forward, direct, and O/D planet set on bearings and isolating that load into, or onto, the center support, which then transmits that load to the case by way of the fretting ring. Doing it this way insures that the planet thrust washer, and selective washer are seeing significantly reduced loads. We are putting a bearing on BOTH sides of the forward clutch hub. On stage 4 and above, we will then rollerize everything under the center support, shore up the planetary clearance, and put the roller bearing between case & output shaft. IMO, just doing the "top" side components (between pump & center support) is more beneficial than messing with everything under the center support. Significantly less machine work for outstanding longevity. I have, to date, never had a unit come back with any significant wear, or any damage, due to these modifications. In fact, the only one I've had come back was due to water intrusion into the unit. When we checked clearances compared to when it was first assembled, and built, it gained less than .004" in end clearance and the planet thrust washer looked brand new still.

One thing I will mention, if you are working on this unit you MUST vacuum test the AFL valve in the valve body, or if you don't have a vacuum test stand, and the unit has 100K miles or more, then install the Sonnax valve, or ream and install an over-size valve. If anyone needs a valve body reamed, I can ream and install the O/S valves and ship the VB to you. I will need your old one back as a core though. Or, you can ship me yours, I'll ream it and install the valve and ship back to you. This valve, along with damaged/clogged AFL screens, are responsible for a LOT of problems. Also, these units after rebuild may exhibit TCC clutch drag.. Be proactive in your rebuild and take steps to insure you don't have this issue. There are Sonnax valves that will preclude this issue, or there are manual changes you can make to your pump if you have it apart that will accomplish the same thing. Always recommended to replace the pump gears, pump bushing, reverse boost valve, when you have the pump apart.

[shootracing22]

Originally Posted by Kawabuggy

Rollerizing the gear train is a great way to prolong the life of the unit in high performance applications, or where towing regularly, or when towing heavy loads frequently. IMO, it is not needed for 95% of most daily driven vehicles that rarely see abuse. We do it at my shop on Stage 3 and above units. It is typically a LOT of work machining everything, and assembling to check clearances as you go. We use a lathe, and a mill, for this type of work.

Lately, I've gotten to the point where we leave everything under the center support alone, and just rollerize everything between the pump, and the center support, and make certain that NO LOAD from the front of the unit is being applied to anything under the center support. This means the forward drum, O/D planetary set, and direct drum are floated on bearings and supported OFF of the sun gear tube, and the intermediate shaft. Essentially we are floating the forward, direct, and O/D planet set on bearings and isolating that load into, or onto, the center support, which then transmits that load to the case by way of the fretting ring. Doing it this way insures that the planet thrust washer, and selective washer are seeing significantly reduced loads. We are putting a bearing on BOTH sides of the forward clutch hub. On stage 4 and above, we will then rollerize everything under the center support, shore up the planetary clearance, and put the roller bearing between case & output shaft. IMO, just doing the "top" side components (between pump & center support) is more beneficial than messing with everything under the center support. Significantly less machine work for outstanding longevity. I have, to date, never had a unit come back with any significant wear, or any damage, due to these modifications. In fact, the only one I've had come back was due to water intrusion into the unit. When we checked clearances compared to when it was first assembled, and built, it gained less than .004" in end clearance and the planet thrust washer looked brand new still.

One thing I will mention, if you are working on this unit you MUST vacuum test the AFL valve in the valve body, or if you don't have a vacuum test stand, and the unit has 100K miles or more, then install the Sonnax valve, or ream and install an over-size valve. If anyone needs a valve body reamed, I can ream and install the O/S valves and ship the VB to you. I will need your old one back as a core though. Or, you can ship me yours, I'll ream it and install the valve and ship back to you. This valve, along with damaged/clogged AFL screens, are responsible for a LOT of problems. Also, these units after rebuild may exhibit TCC clutch drag.. Be proactive in your rebuild and take steps to insure you don't have this issue. There are Sonnax valves that will preclude this issue, or there are manual changes you can make to your pump if you have it apart that will accomplish the same thing. Always recommended to replace the pump gears, pump bushing, reverse boost valve, when you have the pump apart.

Thanks Kawabuggy for taking the time to help me out.
Here is my plan so far. It will be another week before I get time and parts to start working on it again. The truck is more for fun and cruising but I will tow some with it and I plan to shoot for 550hp 1200ftlbs of torque latter down the road so I figured I better do it right.

Hopefully I am off to a good start with the stage five kit from Jakes Performance. BW clutches, 300m input, 36 element super drum, Rollerized billet foward hub, billet main shaft, Sonnax boost valve, 10%+ regulator spring will be a good start. Plus I ordered there recalibration with the 3rd and 4th accumulator block offs. With the their separator plate undrilled. I don't want a super hard shift so hopefully this isn't to bad. My main question here is do I run the factory waves in all the clutch packs or not. I read that some of the waves can break and cause clutch packs to stick.

So far I ordered a set of Sonnex pump gears, Sonnex upgraded pressure regulator spool, Sonnex overrun clutch manifold (plan to run it in OD so hopefully this will help the over run sprag live). Bushings bearings and shims to rollerize the rear case.
I placed an order with CK performance. I ordered his intermediate clutch spring retainer and a the thick pressure plate that makes contact with the HD snap ring (CK says they flex with high line pressure), A modded TH400 piston and hd springs for the direct clutch. Probally should have went with the billet direct piston but to late now.

My plans are and please correct me if I am making a mistake. Also, I do plan to follow the steps in the 2 part Gear Magazine I posted to get all the end clearances right and float the forward, direct, and O/D planet set on bearings and isolating that load on the center support. The forward hub from Jakes should come machined for rollerizing. But I am sure there is more machine work to be done.

1. Rollerize the rear case. Seems pretty easy to do using a Sonnex no walk bushing back wards. a TH350 pump bearing starting with a .020" shim.

2. I am thinking I don't want to go through the trouble to rollerize between the reaction carrier planetary and output carrier assembly. So I am thinking I can used the old rear case thrust here instead of the factory plastic. Currently the reaction carrier has .025" of float. I read a article by Sonnex recommends .010" float. SO I was thinking cant I use the old rear case thrust with a .015" TH350 pump shim to achieve this? Hoping its not a bad Idea and the 4 legs of the thrust will have plenty of material still in the planetary.

3. To keep the thurst from the rear I plan a fit the TH350 pump thrust bearing to the center support by machining it to 0.375” measuring from the front face of the boss, and to an inside diameter of 2.125” and an outside diameter of 2.875”. then shiming it to keep the thrust off the sun gear tube and main shaft. I am think I may have to file the front main shaft if I cant get it to shimmed properly.

Greatly appreciate all the tips. My AFL does have some slack. will most likely just order a $125 transgo kit to install the bigger spool. Hopefully it will last. The Sonnex really seems like the way to go but the reemer is exspensive. Also, I look into my options for correcting the TCC.

[shootracing22]

Here's a few pictures of using the rear thrust in between the reaction planetary and output carrier. Also a few pictures of my tranny teardown.

[Kawabuggy]

My main question here is do I run the factory waves in all the clutch packs or not. I read that some of the waves can break and cause clutch packs to stick.

I think this is a matter of personal choice when it comes to building them.. I always run the wave plate on the intermediate stack. That is the only wave plate I reuse. I also ALWAYS retain the accumulators. You can still get bone-jarring shifts out of your unit even with the accumulators in place so there really is no need to delete them. On that subject, I NEVER set up 4L80E's to shift any harder, or firmer, or faster, than is absolutely necessary for the intended use of the vehicle. I WILL NOT set them up to chirp the tires at low RPM's as some customers request. The gear train in an 80E is HEAVY.. Trying to stop, and or start, drums instantaneously that are spinning at high RPM's is just asking for a short lived tranny, or broken shafts, or wear in various places inside the unit. You can decide how you want your unit to shift, but I caution you that harsh/hard shifts will do you more harm than good with this unit. Your aluminum direct drum will greatly aid in longevity should you set it up to shift hard, but you still have other areas of concern in the unit that will be negatively affected.

A modded TH400 piston and hd springs for the direct clutch. We run the factory intermediate aluminum piston, and factory bonded pistons in the forward & direct. With the wave plate, I can still get 6 intermediate frictions, and Kolene steels, and still have adequate clearance within the clutch stack after milling the backing plate.

On the direct cluth, we discard the wave plate, and put 7 frictions & Kolene steels into this drum, along with a hole drilled along the band surface (between piston and bottom of drum) for faster kick-downs. Doing it this way negates the need for the aluminum direct piston and stiffer springs. We sometimes use the stiffer return springs (sparingly) within the factory retainer on vehicles that we know will be turning 7,000RPM or more regularly. Otherwise, in lower RPM operating ranges, it's not necessary.

think I may have to file the front main shaft if I cant get it to shimmed properly.
You should not have to file ANY of the shafts to get your clearances correct. You will have to shim under the bearing that will sit in the face of the center support to get the drums up, and off of, the sun gear tube. Even after shimming up the drums you will still have plenty of clearance in the front of the unit.

You are on the right track. I would caution you to not try and boost the line pressure too high. These units have plenty of line pressure from the factory. High line pressure will mean very careful selection of the feed hole sizes that you use in the plate. Also, high line pressure paired with no accumulators might be a little more than you expect.

I know you want to only have to "do it once".. But if you set it up too harsh you may come to regret that when it starts tearing up bearings in the rear differential, U-joints, transmission mounts, and hard parts inside the transmission. Be cautious in how you elevate that pressure. It's very easy to surpass "reliable" and wind up in "regrettable".

There is a mod that you can make to your pump since you have it apart. You simply drill a small passage between two divider walls in the pump cover, and it aids in line to lube.
Look here; https://www.google.com/search?q=4l80...464GgPQz5eS0M:

You did not mention it, but I assume you are direct feeding it? I also recommend using the solid white teflon sealing rings on the center support. Yes, they are a bit more difficult to resize once in place, but they do a superior job of sealing as compared to the plastic rings in the rebuild kits. Check the inside of your direct drum very carefully for grooves. If you can catch a fingernail in any of the grooves-get another drum! We actually machine damaged direct drums at my shop and install the Sonnax special bushing that restores sealing ring surface area. If you end up needing a new drum, I will gladly buy your old drum from you. I repair them, and sell them.

Your pics of your unit indicate water inside the unit at some point in it's history. I strongly suggest that you replace EVERY bearing, every thrust washer, all rubber components, and every single bushing (whether you think you need to or not).

If you have any specific questions, you can e-mail me at Transmissionheaven@gmail.com

[shootracing22]

Originally Posted by Kawabuggy

My main question here is do I run the factory waves in all the clutch packs or not. I read that some of the waves can break and cause clutch packs to stick.

I think this is a matter of personal choice when it comes to building them.. I always run the wave plate on the intermediate stack. That is the only wave plate I reuse. I also ALWAYS retain the accumulators. You can still get bone-jarring shifts out of your unit even with the accumulators in place so there really is no need to delete them. On that subject, I NEVER set up 4L80E's to shift any harder, or firmer, or faster, than is absolutely necessary for the intended use of the vehicle. I WILL NOT set them up to chirp the tires at low RPM's as some customers request. The gear train in an 80E is HEAVY.. Trying to stop, and or start, drums instantaneously that are spinning at high RPM's is just asking for a short lived tranny, or broken shafts, or wear in various places inside the unit. You can decide how you want your unit to shift, but I caution you that harsh/hard shifts will do you more harm than good with this unit. Your aluminum direct drum will greatly aid in longevity should you set it up to shift hard, but you still have other areas of concern in the unit that will be negatively affected.

A modded TH400 piston and hd springs for the direct clutch. We run the factory intermediate aluminum piston, and factory bonded pistons in the forward & direct. With the wave plate, I can still get 6 intermediate frictions, and Kolene steels, and still have adequate clearance within the clutch stack after milling the backing plate.

On the direct cluth, we discard the wave plate, and put 7 frictions & Kolene steels into this drum, along with a hole drilled along the band surface (between piston and bottom of drum) for faster kick-downs. Doing it this way negates the need for the aluminum direct piston and stiffer springs. We sometimes use the stiffer return springs (sparingly) within the factory retainer on vehicles that we know will be turning 7,000RPM or more regularly. Otherwise, in lower RPM operating ranges, it's not necessary.

think I may have to file the front main shaft if I cant get it to shimmed properly.
You should not have to file ANY of the shafts to get your clearances correct. You will have to shim under the bearing that will sit in the face of the center support to get the drums up, and off of, the sun gear tube. Even after shimming up the drums you will still have plenty of clearance in the front of the unit.

You are on the right track. I would caution you to not try and boost the line pressure too high. These units have plenty of line pressure from the factory. High line pressure will mean very careful selection of the feed hole sizes that you use in the plate. Also, high line pressure paired with no accumulators might be a little more than you expect.

I know you want to only have to "do it once".. But if you set it up too harsh you may come to regret that when it starts tearing up bearings in the rear differential, U-joints, transmission mounts, and hard parts inside the transmission. Be cautious in how you elevate that pressure. It's very easy to surpass "reliable" and wind up in "regrettable".

There is a mod that you can make to your pump since you have it apart. You simply drill a small passage between two divider walls in the pump cover, and it aids in line to lube.
Look here; https://www.google.com/search?q=4l80...464GgPQz5eS0M:

You did not mention it, but I assume you are direct feeding it? I also recommend using the solid white teflon sealing rings on the center support. Yes, they are a bit more difficult to resize once in place, but they do a superior job of sealing as compared to the plastic rings in the rebuild kits. Check the inside of your direct drum very carefully for grooves. If you can catch a fingernail in any of the grooves-get another drum! We actually machine damaged direct drums at my shop and install the Sonnax special bushing that restores sealing ring surface area. If you end up needing a new drum, I will gladly buy your old drum from you. I repair them, and sell them.

Your pics of your unit indicate water inside the unit at some point in it's history. I strongly suggest that you replace EVERY bearing, every thrust washer, all rubber components, and every single bushing (whether you think you need to or not).

If you have any specific questions, you can e-mail me at Transmissionheaven@gmail.com

THanks again!! Kawabuggy! Really appreciate your input!!!!
I been working on it slowly. I found one bad planet in the rear planetary. I got a replacement from WIT.
I am afraid the overrun planet splines will not be strong hold up so I ordered a new one with a 4140 hub from TCS in Canada.
Unfortunately I a still waiting on my direct drum / Super drum from Jakes Performance. I ordered in on June 22 so its been over a month I am still waiting. They said it will ship Wednesday so I hope to have it Monday.

I ordered the Sonnax TCC spool for the valve body. It comes with 2 springs. I think I will use the stock lock up one.
Also the stage 5 kit came with a boost valve and a higher line pressure spring. I am thinking I should run the stock spring to keep shifts in a more desirable spot. The separator plate that I was supplied by Jakes has the 2nd 3rd feed hole drilled to .115

[YoungPup1977]

Here is another tip:
Use a 200r4 trans center support seal (see pic) to help seal the center support to case on your 4L80E. This will help eliminate any cross leaks on your center support. It fits good into the 4L80E case and seals nicely against the center support. The trans will tell its grand kids you cared. Good Luck !!!