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Rebuilding My 4L80E Transmission

folkenheath said:
How does the quality of that tool seem, does it feel like it will last or is it more of a limited use type tool?
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I would say the quality is fair. For bushings that do not require a whole lot of torque (20 to 25 foot pounds) to get them out it works fine, but for bearings that require a whole lot of torque (70 to 80 foot pounds) to get them out this set may not be up to the task. The great thing about these pullers is they grab hold of the bushing in a place that would be impossible to reach with a regular punch.
 
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Truckman4life said:
Looks like you have to buy the 4L80E video series but after watching his other YouTube transmission videos it would be worth it in my opinion. The Transmission Bench does excellent videos on trans rebuilds and has a really good website for parts also.
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Even though this is a great video it is not the "be all, end all" of videos. After actually getting my hands on my transmission there are a number of small details this video does not cover. It covers all the basics, but there is more to know than this video can cover. I am starting to understand what the experienced transmission builders go through to become good at what they do. It takes actually getting your hands on it to get a grasp of what there is to know.
 
I agree, I read 2 books and looked at a bunch of literature before I did my first auto trans, and during the build I had so many questions I had to get answers too, and this was 15 years ago when it was harder to find the answers if it wasn't in the book.
 
folkenheath said:
I agree, I read 2 books and looked at a bunch of literature before I did my first auto trans, and during the build I had so many questions I had to get answers too, and this was 15 years ago when it was harder to find the answers if it wasn't in the book.
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First time I did a transmission 35 years ago, I had no resources.
I opened it up, laid out all the pieces in order of removal and inspected all the parts then went to the parts store and bought a rebuild kit.
It had all the parts I needed.
Put it together and it worked.
The second I thought I knew what I was doing and it didn't work.
Couldn't figure out what was wrong.
I went to a friend's shop that builds transmissions and asked him.
He said that he would fix it for $100.
But if I wanted to know what I did wrong it was $200.
I paid $200.
The trans was a th350c.
The pump has a little valve for the lockup converter and that valve fell off.
I had a 78 so no lockup converter so he gave me a used regular pump instead.
Years later I came to the states and started getting books and learning and I will get the video.
I built th400 and th700r4.
Next is a 4L80E
 
You'll find the 4L80E is half TH400...the only two I've bothered to rebuild...never opened a 700R4 other than a couple shift kit installs.

I don't do something unless I have a lot of confidence I am doing it correctly. I don't like to assume and just try it. With that said there really isn't much I haven't tackled on a vehicle, with the auto trans being the last piece of the puzzle I had put together it feels like.
 
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I enjoy rebuilding transmissions. I loathe removing and installing them haha.
Looking back I’ve rebuilt a
Th350
4l60e
42re
700r4
46rh
C6
And poked around in a 6l80 and 8l90
 
imiceman44 said:
Didn't you also rebuild your nv4500?
That is next on my list
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Yeah, I was just listing autos. Manuals I think are
NV3550
NV4500
SM 465
And whatever was in my old ‘82 Toyota back in the day haha.
Oh and an Eaton fuller or two. I think a ten spd and a 15 when I was at freightliner.
 
I got all the spool and pressure valves into my pump. Pictured is the Sonnax line to lube spool valve with pressure relief ports, and Sonnax pressure valve with O-ring seals. Also pictured (long spring on left, TransGo spring on right) is a pressure valve spring that is customed manufactured by Jake's Performance that is supposed to give a more consistent line pressure than the stock or TransGo spring does.

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Pump completely assembled with new bushings, seals and pressure valves.
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Got my band servo's installed today. I installed a Sonnax adjustable reverse servo pin kit. Did not have to add any shims to lengthen it. At about 3/4 of servo travel the reverse band engauges enough to the point where I cannot turn the output shaft by hand. That is the best I can do as far as reverse band adjustment goes. The direct drum band servo travels about 80% of the way before in engauges enough to the point I cannot turn the output shaft by hand anymore. There is no adjustment for the direct drum band...it is what it is.

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Ill read through and try to catch up. Are you air testing this as you go? You can air check that low reverse band servo and see the throw and if its too far.

I've built a few 4l80e's, probably 100 or more.

I saw the post about this unit whining all the time. i have personally seen this once. And it was the converter, it was a rebuilt converter doing it to us at that time. we swapped the converter with another rebuilt unit and it was gone.

If it whined in first and reverse, they had a wear problem on the low sun gear. You may know all this already just tossing it in here anyway.
 
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CharlesC83 said:
Ill read through and try to catch up. Are you air testing this as you go? You can air check that low reverse band servo and see the throw and if its too far.

I've built a few 4l80e's, probably 100 or more.

I saw the post about this unit whining all the time. i have personally seen this once. And it was the converter, it was a rebuilt converter doing it to us at that time. we swapped the converter with another rebuilt unit and it was gone.

If it whined in first and reverse, they had a wear problem on the low sun gear. You may know all this already just tossing it in here anyway.
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I found the reason it was whining. The pump bushing behind the input seal was starting to get torn up. I think the reason for this was that I had a SFI flex plate for a T400 or T350 that did not have the off-set 6-bolt pattern that the 4L80E torque converter has, thus I was only running three torque converter bolts. This probably led to some balancing or converter support issues that was probably not good for the bushing. I have gone out and bought the proper flex plate for this build. Going to make sure the converter spacing is correct too. The bushing was not too bad because as soon as my transmission started to whine I parked my truck until I could get the transmission fixed.

I also found that the overrun clutch sprag was going bad too. That was because I was driving my 4L80E around town in circle D. The 4L80E transmission is not supposed to be in circle D around town because when you do that the overrun sprag is handling all the power from the engine. I am going to install a Sonnax overrun clutch valve that will lock the overrun clutches in all the time even in circle D accept in overdrive.

I have a question. Right now I am dealing with setting the end play on my input shaft. should input shaft end play be measured with the pump bolted down or not bolted down?

I have been air testing some of the components as I install them, such as the center support to direct drum, and 4th clutch housing.
 
1-ton said:
I found the reason it was whining. The pump bushing behind the input seal was starting to get torn up. I think the reason for this was that I had a SFI flex plate for a T400 or T350 that did not have the off-set 6-bolt pattern that the 4L80E torque converter has, thus I was only running three torque converter bolts. This probably led to some balancing or converter support issues that was probably not good for the bushing. I have gone out and bought the proper flex plate for this build. Going to make sure the converter spacing is correct too. The bushing was not too bad because as soon as my transmission started to whine I parked my truck until I could get the transmission fixed.

I also found that the overrun clutch sprag was going bad too. That was because I was driving my 4L80E around town in circle D. The 4L80E transmission is not supposed to be in circle D around town because when you do that the overrun sprag is handling all the power from the engine. I am going to install a Sonnax overrun clutch valve that will lock the overrun clutches in all the time even in circle D accept in overdrive.

I have a question. Right now I am dealing with setting the end play on my input shaft. should input shaft end play be measured with the pump bolted down or not bolted down?

I have been air testing some of the components as I install them, such as the center support to direct drum, and 4th clutch housing.
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I would check the end play with the pump torqued and obviously paper gasket installed. At least 4 of the pump bolts or so. You can omit the rubber D seal around the outside of the pump for easier pump removal. Make sure to replace the bolt O-rings with new when going back together.

Sonnax is good stuff. I’d say you’re safer to run around in D more often with that over run sprag in there. But in a larger truck like yours I’d say 3 is better for reducing wear to that but your sonnax part really helps.

The OD piston is tricky to get back together with new lip seals as well.

The paper gasket can handle being torques down a few times and be ok. If it turns into a lot you may want to final assemble with a fresh gasket.
 
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I am having some trouble getting the front end play. When I snug the pump bolts down I have no end play at all. Even with the thinnest selectable pump washer the transmission will spin, but there is no end play at all. Since I have changed some parts and modifications some dimensions have changed. I have to tear my transmission back down to the forward clutch, and recheck all clearances between the forward clutch and the direct clutch. Also have to check clearance between forward clutch housing and the Sonnax billit hub that comes with a roller bearing that is .025" thicker than the stock washer. If I where not such a rookie at this I would have known before I even got this far with the transmission.
 
CharlesC83 said:
Sonnax is good stuff. I’d say you’re safer to run around in D more often with that over run sprag in there. But in a larger truck like yours I’d say 3 is better for reducing wear to that but your sonnax part really helps.
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Since this truck is 80% street driven on Interstate state highways and state highways going up and down mountain passes and running into traffic on busy Interstates, I do not want to do a whole lot of shifting from circle D to manual 3. This Sonnax overrun valve will make long distance cruising a whole lot easer.

CharlesC83 said:
The OD piston is tricky to get back together with new lip seals as well.
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I am thinking about not even pulling the 4th gear piston drum apart. I did a wet test on the drum and the seals seem to be in good condition, What are your thoughts on this?
 
1-ton said:
Since this truck is 80% street driven on Interstate state highways and state highways going up and down mountain passes and running into traffic on busy Interstates, I do not want to do a whole lot of shifting from circle D to manual 3. This Sonnax overrun valve will make long distance cruising a whole lot easer.


I am thinking about not even pulling the 4th gear piston drum apart. I did a wet test on the drum and the seals seem to be in good condition, What are your thoughts on this?
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I’d say you’re safe to not pull the OD drum apart if the clutches weren’t burned.
 
CharlesC83 said:
I’d say you’re safe to not pull the OD drum apart if the clutches weren’t burned.
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The whole transmission was in better shape than I had expected. The clutches, seals, and most bushings looked almost unused. The only bad bushing was the pump bushing behind the input seal. I was looking at a Sonnax tutorial on front end play, and they are saying that input endplay can be measured with the pump bolts only finger tight. With my pump bolts only finger tight I have plenty of end play. It is when I tighten them down to torque spec (18 Ft Lbs.) all the end play goes away. I am going to call Sonnax tech line tomorrow to discuss this with them.
 
1-ton said:
The whole transmission was in better shape than I had expected. The clutches, seals, and most bushings looked almost unused. The only bad bushing was the pump bushing behind the input seal. I was looking at a Sonnax tutorial on front end play, and they are saying that input endplay can be measured with the pump bolts only finger tight. With my pump bolts only finger tight I have plenty of end play. It is when I tighten them down to torque spec (18 Ft Lbs.) all the end play goes away. I am going to call Sonnax tech line tomorrow to discuss this with them.
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No end play at all? Does it still turn freely?


It will be interesting to see what they tell you. Some of the way I do things is just the way the owner at the transmission taught me to. I guess I don’t know if it was the best way or not. Ha. But I did it his way and it worked. He had us tighten the bolts down for checking end play.

Sounds and looks like you’re doing a good job and the transmission will be awesome.
 
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