Rebuilding My 4L80E Transmission

[1-ton]

We cleanup the reverse drum on a lathe, taking off the high spots and polishing it for use with the later band, good move on the Sonnax servo pin

Even if the transmission is a early model 4L80E that originaly came with the grooved reverse band you use the later smooth one? I went to the guy that is working on my torque converter, and he said he could turn output planetary drum for me. It is taking a long time for that guy to get to my stuff because he is the only guy in town that can do what he does on transmissions, and he has people nocking his door down to do work for them non stop.

 

[Greg Ducato]

The type of band used is determined by the Texture of the drum, the early drums were grooved, the later are smooth. If you create a smooth drum by machining then you should use the later band.

 

[1-ton]

The type of band used is determined by the Texture of the drum, the early drums were grooved, the later are smooth. If you create a smooth drum by machining then you should use the later band.

Holy sh!t Batman...that may mean there is nothing wrong with my drum because it has minor grooving in it like the band does. I thought that was abnormal wear.

 

[Greg Ducato]

it will be across the entire surface

 

[1-ton]

it will be across the entire surface

That is what my drum looks like very small minor grooves across the entire surface. Of all the videos I have watch on 4L80E transmissions not one mentioned that the early output reverse drum is supposed to have a lightly grooved texture across the drum, and not smooth like the later models. That is because so many of the videos are using the later model 4L80E as a reference, and not the early models. Thanks for the heads up on this.

 

[Greg Ducato]

If it is flat then use as is with a high-quality early band, it's a very durable combination.

 

[1-ton]

This my rollorized output shaft kit that comes with the Jakes Performance Stage II kit. I have already installed the bushing, the roller bearing, shims, and set the starting output shaft end play. Since my rear planetary turns out to be good I do not have to mess with that. All I am waiting for now is a new low roller sprag, that should be here in a couple of days, for the rear planetary drum. Once I get that I will be able to install the entire output assembly and center support. Then I can set the final output shaft endplay.

 

[1-ton]

Bought this pressure testing gauge for my transmission. Comes with all the adapters to plug it into my transmission after it is put together so I can make sure the pressures are correct. Got it from Amazon for only $25 with free prime shipping and taxes.

 

[imiceman44]

Bought this pressure testing gauge for my transmission. Comes with all the adapters to plug it into my transmission after it is put together so I can make sure the pressures are correct. Got it from Amazon for only $25 with free prime shipping and taxes.

Thanks for mentioning this.
I am in the process of getting the tools and learning from guys documenting their rebuild like you then I will tackle my first 4l80E.
I have done a few th350 with success, and all I had was a bad trans, a basic rebuild kit, I took it apart and put it back together in the right order.
I don't think a 4l80E will be that simple, looks like lots of adjustments and clearance checks so I am taking my time to see a few rebuilds.
I also got my ATSG manual and I will probably get the same kit you got and the video

 

[mrk5]

Thanks for mentioning this.
I am in the process of getting the tools and learning from guys documenting their rebuild like you then I will tackle my first 4l80E.
I have done a few th350 with success, and all I had was a bad trans, a basic rebuild kit, I took it apart and put it back together in the right order.
I don't think a 4l80E will be that simple, looks like lots of adjustments and clearance checks so I am taking my time to see a few rebuilds.
I also got my ATSG manual and I will probably get the same kit you got and the video

If you decide to do the Actuator Feed Limit Valve Repair Kit, TransGo 48-ACT-TL, post up in the Wanted section as there are several guys here on CK5 that have extra. The kit comes with enough parts to do 6 transmissions. It's the only way you can get it.

 

[imiceman44]

If you decide to do the Actuator Feed Limit Valve Repair Kit, TransGo 48-ACT-TL, post up in the Wanted section as there are several guys here on CK5 that have extra. The kit comes with enough parts to do 6 transmissions. It's the only way you can get it.

I will, but I also might just get the kit since I have 3 4l80E transmissions

 

[1-ton]

Been a couple of weeks since my last update on my 4L80E build. Took a while to get some parts and tools together. Transmission parts and tools do not fall off of trees. I finally got my direct drum back together. I installed a heavy duty set of cage springs on it. Had to get a tool designed to compress cage springs because these heavy duty springs are so much stronger that my make shift cage spring compressor would not do the job. I also drilled out a bleed off hole on the direct drum, and removed the inner seal which is another mod made to the direct drum so that the piston has more surface to grab onto. I also installed the 34-element sprag that came with the rebuild kit into the direct drum. My direct drum actually still had the old style 16-element sprag in it.

 

[folkenheath]

Now you can add a transbrake without removing the trans...

 

[1-ton]

Now you can add a transbrake without removing the trans...

Being that this is a 1-ton crew cab I do not think I need a trans brake even though my rebuild kit did come with some of the parts required to make it into a manual valve body.

 

[folkenheath]

I was just joking mainly because you drilled the bleed hole and added the springs in the direct drum, which every transbrake that I know of requires. The rest can usually be done by pulling the pan.

 

[wasted wages]

Being that this is a 1-ton crew cab I do not think I need a trans brake even though my rebuild kit did come with some of the parts required to make it into a manual valve body.

So no 1/8 mile 4 wheel drive holeshot videos forthcoming?

I am depressed.....

 

[1-ton]

I was just joking mainly because you drilled the bleed hole and added the springs in the direct drum, which every transbrake that I know of requires. The rest can usually be done by pulling the pan.

I figured you where being sarcastic since you know what vehicle this transmission is for. The modifications to the direct drum are for getting it to hold harder in third gear, and the bleed off hole for any high pressures that could cause the 2 & 3 gears to try to engage at the same time. These are two known problems that the 4L80E have...not holding well in third gear, and trying to engage both 2nd and 3rd gear at the same time, thus causing drag in the transmission under any high pressure conditions. I am also doing the internal dual feed, and drill out the valve body separator plate port holes a small amount.

 

[1-ton]

I think I may have found the problem with my transmission. It had a bad roller sprag in the overrun clutch. When I removed the planetary gear from the overrun clutch a couple of rollers and springs fell out of the sprag. When I inspected the roller sprag closer I could see there was a small crack in the plastic sprag cage. My transmission had a whining noise all the time whether it was in park or in gear, and since the overrun clutch planetary is splined into the input shaft it is spinning all the time around the roller sprag.

 

[folkenheath]

The moment you put it in gear and the vehicle is stationary that would be stopped, because the input shaft is only spinning if the converter spins it, which is barely at all at idle if its in neutral and free spinning, and should be stopped when you put it in gear until you accelerate. Because once it is in gear the power transmission shafts are then connected to the output shaft at some gear ratio. So if the wheel speed is zero, the input shaft speed should then be zero.

I still believe it would be in the pump, which is directly connected to the converter case, which is bolted to the flexplate, and the same RPM as the engine.

 

[1-ton]

I still believe it would be in the pump, which is directly connected to the converter case, which is bolted to the flexplate, and the same RPM as the engine.

I still have not gotten around to looking at the pump pressure valves. I have inspected the gears and bushings, and they where all in very good shape.