On What Lies Within

I wasn't sure what to do from the outset of this process, to be honest. [I'm going to turn this into a drinking game. Every time I say, "I'm not sure what to do" you have to take a shot! -SW] On one hand, I took a look at what was involved in rebuilding a gearbox and reckoned that maybe it was best to leave everything alone. For one thing, I don't have a lot of budget at the moment; it can be a super expensive job. Parts are available, fortunately, but getting them can be a pain. 

Compounding this problem was the fact that I didn't know if the gearbox was working or not when I acquired the vehicle. I kind of assumed that it would be, given it was moved around (I presume) in the mid 2000s before it was last laid to rest, but I couldn't know for sure. 

Fuckit. I can pull things apart basically for free, and taking a look at the state of things is useful information I can gather to determine if it's more feasible to source a good used gearbox or just replace a few parts on mine. 

So I pressed on with the next steps in the shop manual, which is to take the now-separated components and disassemble them individually. The main gearbox is listed next in the Haynes manual, so that's where I started. 

You begin by taking the bellhousing off the front of the gearbox. To do this, you have to take the clutch mechanism and its housing off the gearbox. It is only a few lines in the manual and it's not too complicated. 

In my case, of course (of course!) I had trouble. One of the nuts on the end of the loooooooong studs going through the clutch release mechanism refused to turn and just loosened the stud in the housing. It was so oily and grimy thanks to some kind of seal failure that it was quite stuck on there. Also unfortunately, the stud didn't want to come out with the nut for easy access later. So the whole release mechanism was stuck on the bellhousing thanks to one stuck nut.

Sigh.

I managed to solve this problem by getting an impact gun on the nut which broke it 'free enough' that I could spin it off. After that, the clutch release mechanism came out fairly easily.  

Should the clutch release mechanism have this dark, oily mud / soup goo at the bottom of it? [Edit: No. No it should not.]

I also took off the bracket for the hi/lo selector lever on the bellhousing. As you can see, it's super worn. Pretty sure the hole is not supposed to be ovoid. It's covered in oil-glued sand, which probably explains some of the wear on the part. Not sure there's supposed to be oil on the bolts, either. 😐

I also took apart the clutch release pivot pin / thing:

It's pretty worn and wobbly. I have a feeling I'll need to source new components so that this system, which looks really, uh, "farm-grade" (with sincere apologies to my agricultural readers), has any chance of working in the future. 

With this truck there is always at least one stud holding a given part which, when removed, comes out with its nut stuck firmly to it. Every damn time.

Whatever, that's a problem for another day. Time to get the big bolts holding the bellhousing on and remove 'em!

Success!

Though you see what I mean? Three bolts will come out and sure enough, the nut that's attached to a stud *always* comes out. 

This is what the now-removed bellhousing looks like, with the input shaft attached via its bearing and retainer plate. 

There are some interesting things to see in the above photo. First is the worn in... grime? corrosion? schmoo? that's on the back of the input shaft. The back of it is clean on the mating surfaces, except where it's exposed to the open air inside the gearbox. That black sh*t is stuck on there, like seriously stuck on there. I'm having to scrape it off to clean the part. I don't think it's corrosion, but it sure is gritty like corrosion.

You can see the hand-fashioned inspection plate on the top of the bellhousing. It's supposed to be a "D" shape -- you know, kind of like the Anaheim Ducks hockey logo -- but instead it's an oval that someone cut out of sheet metal. No gasket of course. Hmm.

Anyway, on to pulling the parts out of the gearbox!

Here is what it looks like once you get the selectors, the selector housing, the mainshaft, and the layshaft removed. I didn't get many photos, unfortunately. One's hands get really covered in old gear oil and it's a fairly involved process to get everything disassembled. I just followed the manual and laid everything out on the bench. It definitely helps to have a couple of things: 1) good lighting in your work area; 2) lots of space to lay out parts once they come out of the gearbox; and 3) the right tools to make the job a lot easier. On this generation of gearbox, nearly every fastener is BSF so whitworth spanners are a must. I also highly recommend a really good pair of circlip pliers. Mine are Chinese-brand-but-decent and they will bend on some of the bigger, stronger circlips. 

Just for fun, I snapped a pic (when I was done) of all the tools I used:

Here's an enlarged pic of all the 'mud' in the bottom of the gearbox. I expected there to be some in there, for sure. But I did not expect this much slime in the bottom. It's quite worrying, to me at least, that this much silt suspended in oil is sitting at the bottom of the gearbox. Metal flakes, sand, and other powders get suspended in the EP90 and a lot of this goo ends up on the mating / bearing surfaces. It can't be good for them, surely. 

It took quite a few shop towels to wipe out the goop:

I dunno if your projects go like this but for me, after some time spent working in gearbox slime, all I wanna do is clean something -- anything -- so that it's done, or done-ish, and looks like it could be ready to go back on the truck. 

So I took an hour and a bit to clean up the front output housing. It was totally stripped, so access was easy. And it was kind of mostly clean already thanks to the oven cleaner. Out came the simple green, scraper, wire brushes, scotchbrite, and (eventually) a sanding block. 

Why the sandpaper? I wanted to get the mating surfaces as flat, clean, and smooth as possible. The goal would be to give any gasket I put in there a fighting chance at holding in oil. 

Getting the last of the stuck-on grease / oil ended up being a big challenge though, so I left it soaking in a bucket of degreaser & water for a couple of days to try and loosen some of it up.