4L80E build, things to be mindful of
4L80E build, things to be mindful of I wanted to start a thread of things to be mindful of for someone looking to build a 4L80E for the first time. Things that aren’t covered in youtube videos or not explained very well in build manuals and such. Note that this list does not include all the various lubrication mods or machining of parts for improvements as well as various other tricks that can be performed, as all that information is contained in various other threads on this site.
Most of this information comes direct from vorteciroc, MaroonMonsterLS1, jakeshoe, truckdoug and others from the numerous threads that I’ve read over the years. Some of the information they have generously shared with us has been compiled below. Consider this list is as a work in progress and a very poor initial attempt to put this together, as there’s much more to add to it.
I plan to add to this over time as I read about folks that have issues on their builds that was due to an oversight, as every bit of information helps those attempting a 4L80E rebuild. Mainly I want to link to this page and use it as a reference whenever the common question comes up “in addition to watching videos and getting an ATSG manual, what are some of the other things I need to be aware of?”
Hard part/case inspection
1. Inspect the case for damage and cracks.
2. Inspect the case for broken lugs
3. Inspect the pockets in the case where the check ***** go. They may needed filed down. Some like to use torlon checkballs in this location if the pockets look bad.
4. Sand the worm track surface of the valve body and the case with a sanding stone. Also do the same for both pump halves where they contact each other/contact an aftermarket pump plate.
5. Ensure that the center support to case sealing area has a good finish on both contact areas.
6. Inspect center support for cracks/leaks.
7. Inspect center support to ensure that it has not rotated out of position
8. Inspect wear on the separator plate. For $5, it’s suggested to replace it all together with new.
9. Inspect the accumulator inside the low band servo. 2nd gear fluid can bleed off from here. The 2nd accumulator piston seals are not the best, iron sealing rings from a TH400 are better.
10. Use a scotchbrite pad on the bores of the accumulator and reverse servo.
11. Inspect the condition and prep of the low-reverse band surface (this surface prep determines whether of not a smooth band lining is used)
12. Measure the diameter of the low-reverse band surface (for proper low-reverse servo operation/ clearance
13. Inspect pinions/gears/ and shims on all planetaries, and check clearances. When they get higher than .025” worth of play, it’s time to replace or rebuild the planet.
14. Measure all clearances for the gears to the pump. OEM pump gears are best. Gear to face clearance of .0007 - .0028”, outer gear to pocket of .0015 to .008”, inner gear to crescent of .002 - .012”
15. Inspect pressure plate surfaces for wear. Replace/address as needed.
16. Check the inner sleeve of the forward drum where it makes contact with the o-rings on the input shaft. This is a common wear area and the forward drum often needs replaced. It can be machined with a new sleeve but compare cost of buying new vs labor/time to machine.
17. Inspect the mesh of the sun-gear with the planet
18. The sun tube bushings are finish in place. Aim for .0015” clearance using a flex hone or brake hone.
19. Inspect the surface (ramps and pockets) where the low-reverse one-way roller-clutch makes contact.
20. Inspect the contact of all parts with the new bushings.
21. Assemble the unit on the bench, and make sure everything rotates as it should both in and out of the case when assembling. Rotating the output shaft clockwise will be harder than counter-clockwise.
22. If the bushings are not in straight, (it’s highly recommended to press them in, not pound them in) there will be binding issues. Check that the case bushing is in straight by putting the output shaft into the case after installing the bushing, and banging on it with a rubber mallet in a star pattern.
23. Ensure that the snap ring on top of the center support is fully installed into the groves. If it’s not, is a sure sign that the stack is too high because a bearing was flipped or something overlooked causing the height to be incorrect.
24. Inspect clearance/ fitment of the bushing to the inner race on the center support (clearance should be 0.0015" to 0.003")
25. Inspect the condition of the inner race surface on the center support (surface must be undamaged
26. Never remove the inner race from the center support yourself if damaged (easiest and cheapest solution is to replace the center support)
27. Inspect the sun gear thoroughly. Look for nicks and chips in the gear.
Replacement part notes
1. Be mindful of mixing and matching parts from various year transmissions. Some parts play well together, some don’t.
2. If replacing the main shaft, get an early shaft with hollow center and machine the end to get proper fit and endplay, most of these need .060 shaved off.
3. For the forward clutch if you are going to use a wave, use the th400 style thick wave. The late 4L80e waves are really thin and can get stuck under the "cleanout groove" and cause and issue or they crack.
4. Whenever using a TH400 early aluminum or billet piston in the direct drum that has been machined to increase the clutch pack clearance for thicker steel plates/additional friction plates, be mindful of the presence of a check ball. Some have them, some don’t. No checkball in the piston and the direct drum is a problem. A checkball in one of the two parts = good. A checkball in in both parts = not a problem, but not really ideal. If the drum has a check-ball hole, leave it alone. If the piston also has a check-ball hole; knock out the check-ball, and tap the hole for a small set screw.
5. Strongly consider the use of a pump plate in-between the pump halves.
6. High-rate" springs should be used for the direct clutch when "dual-feeding” and replace the stock springs. Often the solution here is to use a TH400 spring retainer plate and a billet surface for the springs to seat in on a stock piston, the stock spring cage is flimsy. A billet or TH400 early aluminum piston is another option.
Testing
1. Vacuum test the valve body and pump. See the Sonnax site for more details on this.
2. Air test the various circuits for seal blow out/leaks by blowing air into the case prior to installing the VB.
3. Check line pressure with a GOOD mechanical gauge from a well known manufacturer.
4. Check the TCC valve and circuit for leaks.
5. Measure the resistance of all electronics, even if they are brand new.
6. Ohm out all wires on the internal and external harnesses.
7. Ensure that endplay is correct in all 4 locations. Note that endplay tolerance of rollerized setups varies from non rollerized.
General
1. Ensure that the center support bolt is properly torqued
2. Make sure that the bolts that are used to secure the accumulator housing to the VB aren’t accidently used to secure manifold pressure switch to the case. They are a different length and can cause issues if they are mistakenly swapped.
3. Set the clearances in each clutch pack correctly.
4. It’s a good practice to replace the AFL and TCC in all valve bodies (you should vacuum check to determine if this needs done) but many don’t vac check and just ream the AFL bore and use an oversize AFL valve and a new TCC valve.
5. Ensure that the reverse servo apply travel has the correct amount of travel.
6. Calibrate the dipstick tube to be ¼” above the pan rail. Verify "full" level on the dipstick when fluid is hot and vehicle is on a level surface.
Most of this information comes direct from vorteciroc, MaroonMonsterLS1, jakeshoe, truckdoug and others from the numerous threads that I’ve read over the years. Some of the information they have generously shared with us has been compiled below. Consider this list is as a work in progress and a very poor initial attempt to put this together, as there’s much more to add to it.
I plan to add to this over time as I read about folks that have issues on their builds that was due to an oversight, as every bit of information helps those attempting a 4L80E rebuild. Mainly I want to link to this page and use it as a reference whenever the common question comes up “in addition to watching videos and getting an ATSG manual, what are some of the other things I need to be aware of?”
Hard part/case inspection
1. Inspect the case for damage and cracks.
2. Inspect the case for broken lugs
3. Inspect the pockets in the case where the check ***** go. They may needed filed down. Some like to use torlon checkballs in this location if the pockets look bad.
4. Sand the worm track surface of the valve body and the case with a sanding stone. Also do the same for both pump halves where they contact each other/contact an aftermarket pump plate.
5. Ensure that the center support to case sealing area has a good finish on both contact areas.
6. Inspect center support for cracks/leaks.
7. Inspect center support to ensure that it has not rotated out of position
8. Inspect wear on the separator plate. For $5, it’s suggested to replace it all together with new.
9. Inspect the accumulator inside the low band servo. 2nd gear fluid can bleed off from here. The 2nd accumulator piston seals are not the best, iron sealing rings from a TH400 are better.
10. Use a scotchbrite pad on the bores of the accumulator and reverse servo.
11. Inspect the condition and prep of the low-reverse band surface (this surface prep determines whether of not a smooth band lining is used)
12. Measure the diameter of the low-reverse band surface (for proper low-reverse servo operation/ clearance
13. Inspect pinions/gears/ and shims on all planetaries, and check clearances. When they get higher than .025” worth of play, it’s time to replace or rebuild the planet.
14. Measure all clearances for the gears to the pump. OEM pump gears are best. Gear to face clearance of .0007 - .0028”, outer gear to pocket of .0015 to .008”, inner gear to crescent of .002 - .012”
15. Inspect pressure plate surfaces for wear. Replace/address as needed.
16. Check the inner sleeve of the forward drum where it makes contact with the o-rings on the input shaft. This is a common wear area and the forward drum often needs replaced. It can be machined with a new sleeve but compare cost of buying new vs labor/time to machine.
17. Inspect the mesh of the sun-gear with the planet
18. The sun tube bushings are finish in place. Aim for .0015” clearance using a flex hone or brake hone.
19. Inspect the surface (ramps and pockets) where the low-reverse one-way roller-clutch makes contact.
20. Inspect the contact of all parts with the new bushings.
21. Assemble the unit on the bench, and make sure everything rotates as it should both in and out of the case when assembling. Rotating the output shaft clockwise will be harder than counter-clockwise.
22. If the bushings are not in straight, (it’s highly recommended to press them in, not pound them in) there will be binding issues. Check that the case bushing is in straight by putting the output shaft into the case after installing the bushing, and banging on it with a rubber mallet in a star pattern.
23. Ensure that the snap ring on top of the center support is fully installed into the groves. If it’s not, is a sure sign that the stack is too high because a bearing was flipped or something overlooked causing the height to be incorrect.
24. Inspect clearance/ fitment of the bushing to the inner race on the center support (clearance should be 0.0015" to 0.003")
25. Inspect the condition of the inner race surface on the center support (surface must be undamaged
26. Never remove the inner race from the center support yourself if damaged (easiest and cheapest solution is to replace the center support)
27. Inspect the sun gear thoroughly. Look for nicks and chips in the gear.
Replacement part notes
1. Be mindful of mixing and matching parts from various year transmissions. Some parts play well together, some don’t.
2. If replacing the main shaft, get an early shaft with hollow center and machine the end to get proper fit and endplay, most of these need .060 shaved off.
3. For the forward clutch if you are going to use a wave, use the th400 style thick wave. The late 4L80e waves are really thin and can get stuck under the "cleanout groove" and cause and issue or they crack.
4. Whenever using a TH400 early aluminum or billet piston in the direct drum that has been machined to increase the clutch pack clearance for thicker steel plates/additional friction plates, be mindful of the presence of a check ball. Some have them, some don’t. No checkball in the piston and the direct drum is a problem. A checkball in one of the two parts = good. A checkball in in both parts = not a problem, but not really ideal. If the drum has a check-ball hole, leave it alone. If the piston also has a check-ball hole; knock out the check-ball, and tap the hole for a small set screw.
5. Strongly consider the use of a pump plate in-between the pump halves.
6. High-rate" springs should be used for the direct clutch when "dual-feeding” and replace the stock springs. Often the solution here is to use a TH400 spring retainer plate and a billet surface for the springs to seat in on a stock piston, the stock spring cage is flimsy. A billet or TH400 early aluminum piston is another option.
Testing
1. Vacuum test the valve body and pump. See the Sonnax site for more details on this.
2. Air test the various circuits for seal blow out/leaks by blowing air into the case prior to installing the VB.
3. Check line pressure with a GOOD mechanical gauge from a well known manufacturer.
4. Check the TCC valve and circuit for leaks.
5. Measure the resistance of all electronics, even if they are brand new.
6. Ohm out all wires on the internal and external harnesses.
7. Ensure that endplay is correct in all 4 locations. Note that endplay tolerance of rollerized setups varies from non rollerized.
General
1. Ensure that the center support bolt is properly torqued
2. Make sure that the bolts that are used to secure the accumulator housing to the VB aren’t accidently used to secure manifold pressure switch to the case. They are a different length and can cause issues if they are mistakenly swapped.
3. Set the clearances in each clutch pack correctly.
4. It’s a good practice to replace the AFL and TCC in all valve bodies (you should vacuum check to determine if this needs done) but many don’t vac check and just ream the AFL bore and use an oversize AFL valve and a new TCC valve.
5. Ensure that the reverse servo apply travel has the correct amount of travel.
6. Calibrate the dipstick tube to be ¼” above the pan rail. Verify "full" level on the dipstick when fluid is hot and vehicle is on a level surface.
