E4OD post-mortem, rebuild and upgrades

13 years after I built this unit, it finally let go in the middle of summer 2020.

Early warnings:

Reverse was getting somewhat weak over the last few months and adding power seemed to add a "clunk" of sorts where a sudden surge of torque was instantly applied. Thinking back, this was likely a slipping clutch.

3-4 shift seemed a bit crisp but I added an extra friction so I didn't think much about it until after the teardown. Work close to home also means the truck seldom used overdrive for the preceding several months.

Late Warnings:

First indication of a major problem was the truck seemed reluctant to get all the way down into 1st gear when coming to a complete stop. Usually I can feel a slight nudge just before the truck comes to a stop (2-1 shift). Instead, the transmission would kickdown to 1st while pulling away, which is not normal.

Within about 1 hour of driving in light urban conditions, it was already slipping so bad it could barely climb any hills at all. I barely limped it home and tried again in the morning. When cold everything seemed fine but as it warmed up, the slipping returned to the point where it could barely move. It was done.

The rebuild is already complete so what you'll see in the next few posts is what you get. I may have a few other photos but this won't be an exhaustive thread. I'll focus mostly on the post-mortem and the mods that I added for this time around.

So it's come to this:

 

For anyone interested in doing this job themselves, I strongly encourage you to get both ATSG manuals:

1. Rebuild Manual

2. Update Manual

They are still available in paperback or digital copies. I have been able to find both online in PDF form now so they are not hard to find. I probably shouldn't post here, however due to copyright concerns.

One other source that proved invaluable is an attached article that describes checkball functions in the transmission. Mine has the Baumannator shift-kit, which is no longer supported. So it took some study time to figure out the modifications. I emailed US Shift if they still had the old manual on file and they never responded. This is a public article, so I don't think there are copyright issues but the Mods can remove if there are.

 

Post Mortem begins...

First off, the torque converter pump gear was installed backwards. Major egg on my face here. This explains the problems I had with the offset of the E4OD compared to the C6. How I screwed this up, I'll never know, but I did.

This caused damage to the converter hub and the pump gears. Fortunately, the pump case was salvagable and I was able to machine the case to accept the Sonnax oversize pump gears. Setup on the lathe was a nightmare on a 3-jaw chuck, but I was able to get the tolerance recommended by the kit (not recommended to try this at home).

Next problem was the overdrive return spring snap ring had popped off. This explains the hard 3-4 shift I mentioned in the first post. As it turns out this won't necessarily cause a catastrophic failure with the original style aluminum apply piston. From what I've read, the later bonded steel piston (circa 4R100) are another story. So a spiral snap ring will most certainly go in this time.

First indicator of a major failure was the tiny steel balls shown in the attached photo. These are the ball bearings from the center support. And every last one of them flew out.

 

Here is the sonnax pump gear kit I used:

https://www.sonnax.com/parts/2075-oversized-pump-gear-set

I checked for binding and clearance on the converter after the machining was done and all fit perfectly. Also shown is the new sonnax metal anti-drainback valve

 

So back to the center support. Once the roller bearing failed, alignment to the sealing rings also failed and likely caused a massive loss of hydraulic pressure (AKA internal bleeding). This is probably where my sudden failure came from. However, looking at the original symptoms, problems were appearing before then.

I wasn't able to photograph this, but it turns out the intermediate clutch apply piston seal was installed backwards. This is a lip seal, so it should only go in one way, with the lip facing the high pressure. With this, a bigger picture starts to form.

Pressure loss for any gear above 2nd was likely the result of this. If you look at the shift table in the manual, clutches are added to produce the next gear in the transmission. The higher the gear, the more clutches are required. The E4OD does not shift by releasing one clutch and simultaneously applying the next; the 4R110 does but that's a different animal that uses software to get the timing right. So chances are, this may have been bleeding fluid pressure and lubricant from early on.

It may have also helped explain the weak reverse engagement over the longer period of time, since more engine RPM seemed enough to add enough fluid. The backward pump gear likely didn't help either.

So that takes care of the teardown and post-mortem. And also gives me a parts list:

1. New Sonnax modified center support: https://www.sonnax.com/parts/2080-center-support-ring
Shoutout to Youtuber, Precision Transmissions for showing this in one of their videos. I would have never caught this issue otherwise. Sure enough, my center support did have notches carved into it from the lugs on the case. Hard to say if this contributed to the overall failure.

2. New Direct Drum (moderate damage)

3. New Intermediate Drum (moderate damage)

4. Overdrive stub shaft (minor damage)

5. New Overdrive Sprag (minor damage)

6. 6 pinion steel reverse gear setup circa-4R100 (minor damage to original 4-pinion aluminum setup)

7. 45 Element intermediate Sprag (no damage, but wanted the upgrade)

8. Billet Converter (worried about debris, so asked the original shop to rebuild)

9. Sonnax converter drainback valve (transmission got hot, so I didn't want to risk a melted valve here)

10. All Raybestos red clutch packs

11. Transgo Tugger kit came with the rebuilt kit, but I kept the updates mild (no drilling on the separator plate)

12. New solenoid body (not rebuilt)

I've likely forgotten some items on this list so I may circle back to add photos and other edits. This rebuild dragged out over more than 6 months, so it's a bit hazy now...

 

Now for some of the upgrades. First off was the torque converter.

I asked the builder to send me photos after he tore down my converter. Apparently it was mint inside so the rebuild wasn't needed. However, I really don't want to have to do this again.

 

Here's another clearance issue I had with the E4OD conversion 13 years ago. This wasn't related to the pump gears.

The crank shaft bolts actually press against the hub of the billet front cover. This isn't an issue on the OEM stamped cover because there is more room on those. I explained this to the builder and sent the flexplate and crank bolts in the crate along with the core. He said this is a common problem and machined down the front of the cover slightly to allow clearance for the crank bolts. Keep in mind, this is a C6 flexplate, so I'm not 100% sure if the problem would occur on any IDI engine with a billet converter.

 

The rebuilt converter ended up being a 6-stud. I didn't directly ask for one but rather ask if it would be a good idea. The builder ended up giving me one free of charge after he reread my email on the topic. No harm I suppose, but it did mean having to modify my flywheel and flexplate now.

Drilling the flexplate is relatively simple, since it's thin steel and doesn't represent a lot of mass. Simply tools and a drill press are really all that's needed. Keep in mind the centering is done at the hub of the assembly. Not that you want the holes to be off, but it's not catastrophic if they are.

 

The flywheel is another story. This is a big piece of heavy iron and needs to be drilled accurately. I tried doing this the same way but ended up having to do it on the CNC. Fortunately we have one and my Dad was able to do the work for me. So with that, this IDI is now going together with a 6-stud billet converter.

 

Before we get any further, a little PSA on the E4OD. Attached are photos of the output shaft snap ring. Don't ever try to reuse these. The rebuilt kit didn't come with one, and it was actually quite challenge to try and order one separately. Covid was also interfering with many of the businesses I tried ordering from in the states.

In any case, the reason you can't reuse them is they will deform when install them, and deform even further when you remove them. The photo shows the difference between used and new. Also, don't install the snap ring using pliers. the correct way is to slide it down the shaft until it snaps into the groove. If you use snap ring pliers, you will open it more than necessary and again deform it.

I ordered two snap rings just in case I needed to backtrack for some reason.

 

Now for some of the secret sauce.

Alto offers kits that increase the number of friction elements in each clutch pack. This is accomplished by making thinner frictions and steels so the stack height still fits in the same location. I opted for modifying the backing plates instead. This is how it's generally done at the factory, and I preferred using thicker elements.

Here's the modification to the direct clutch pack (2-3 shift).

First, the outer edge of the plate needs to be machined down to allow for an extra friction and steel. The trick is, you can't machine the whole thing down, or it will become too weak. You also can't machine it as a square notch, or you can't get the snapring in and out. So I turned it down in stages, taking time to check the clearance and make sure I didn't take off too much. You can see the stepped pattern from this rough machining where I'm checking the clearance.

Once I was happy with the stack clearance, I cleaned up the top of the plate and then deburred it.

As for how I arrived at this stack height, I used the manual's recommendation, then increased it slightly to account for the extra friction set (Basically, multiply the stack clearance by 1.20 ~ 1.25).

 

Now for the even more risky modification: Intermediate clutch.

Although this clutch pack has a nice and thick backing plate, you can't use all of it. this plate lands against the case where a radial groove is cut, so if you take too much off, it won't engage the case lugs. That being said, I was still able to fit an extra friction set (upgrade from 3-4).

This is not a simple job and requires a great deal of caution, measurements and double checking your work. Unlike the other clutches, the clearance on this is not so easy to measure. Material has to be taken off the end plate, but also from the intermediate apply piston. But eventually I was able to get it within spec, while still having plenty of engagement on the case lugs.

 

A safer modification was the case vent. Later E4ODs and 4R100s had a better setup than the crimped cap on this one. Since this truck is now officially a 4wd, there is a slim possibility of going through deeper water and one of the things I planned to do is route vent hoses up into the body to prevent the transmission, transfer case or axle housings from ingesting water. As it so happened, I had a spare banjo fitting from a turbo kit lying around, so I used that to attach a hose to the top of the case. From there, the hose goes up to the firewall.

The original vent is press fit in (not threaded). The new banjo fitting required thread tapping to work on the case. Cuttings were cleared by blowing compressed air out from the inside port.

 

Richard is an inspiration on many levels (YouTube Channel: Precision Transmissions, for those who aren't familiar). It always hits me in the feels when I see a Father and Son getting along like that (I was similarly blessed in my life). Also glad to see him back to work after his surgery. Heh, his first teardown after returning was a 4R100.


Early indicators my E4OD are good but I've only been able to run the transmission on blocks since I'm waiting for one of the front fenders to come back from the paint shop.

Engagement in forward or reverse is 0.8 seconds (!!!!). I timed it repeatedly and came up with a similar number every time. This is huge for me because reverse engagement was usually 1 to 2 seconds. I removed the wave plate so it is a little more positive but I'll take it. I think the reverse clutch clearance was 0.065" 13 years ago, since ford had no official recommendation and the ATSG manual didn't have a number either. Since then I found other guys that are running them closer to 0.040", specifically to deal with delayed reverse. Mine is right around 0.045" now, which may have helped reduce delay. The Tugger kit also recommends removing 1/3 of the return springs for the reverse piston on this vintage of E4OD, which I did not do. Later E4OD/4R100s have smaller springs.

Manual low is also instantaneous, which may be partly due to the new accumulator springs from the transgo tugger kit. Shifting down into manual 2 or 1 was always sluggish before, and according to the transgo documentation, indicates slipping. Now, I can manually start in 1, then manually shift into 2 and the upshift is instant. Drop back down to 1, and it's again instant (even at idle engine speed). I can go from 3rd gear straight down to 1 and the downshift is still completed in about 0.5 seconds. Very crisp operation. I haven't shifted into overdrive since wheel speed would be to high to safely run on blocks, but the 3-4 shift was always good, even with the old build. I might try a custom program just to engage 4th at lower speed and help clear any air in that circuit before the road test.

There are so many things I replaced that I think its hard to really say if any one upgrade or repair had the most effect. I can't wait to see what the road test is like.