Build Mitsubishi 4D34-3AT3B diesel swap into 94 FZJ80

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I am now down to 1 hour for trans removal and about 2 for reinstall. I started lifting the front end with the floor jack at 7PM and by 9:00 I had everything laid out on the bench, right down to the check balls in the valve body.

The worst part about it is definitely the sheer weight of the trans and transfer case. It's a funny feeling working under it and knowing that if it falls off the trans jack, it's gonna leave more than a mark...

I also sent Rodney at Wholesale Transmissions an e-mail regarding the lockup issue. I doubt he is familiar with the Aisin trans but I think it is probably a closer cousin to the A442F found in the later 100 series 1HDT truck. Next time I see Eleblanc we will have to compare the A442F in his 100 and this trans to see if they are similar - IE no mechanical throttle pressure cable...

So, to expand on the control side of things, I re-read the manual this weekend and the computer does not have a whole lot of parameters to look at for lockup. Temperature is a big one, so is throttle position, and the output shaft speed, presumably versus the crank RPM provided by the ECM. So, really other than an ECU issue, there are not too many inputs necessary to make it work.

What's been confusing me is why the TCM is not energizing the lockup circuit. The temp is within range, the input and output speeds should be within range, and all other parameters should be OK.

I obviously had a mechanical issue, which is hopefully rectified, and I am hoping that somehow this corrects the control side of things, but the line pressure issue I had would not automatically result in no-lockup as the computer does not "see" the line pressure. Perhaps it's seen indirectly by monitoring the output RPMs and pedal position, it seems like the pedal position is less than it was before...

I will try and top it up and see how it goes.
 
Fromage said:
Between the center support and the main case. One of the three O rings right where the valvebody pressure connections are. I believe it was the center one.
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Those are the one prone to getting cut. Kind of a bad design - having to slide a compressed o-ring sideways over the hole it is supposed to seal. Of the several Aisin transmissions that I disassembled, I found several of those o-rings damaged and the only way that I can see them getting damaged is during reassembly.

Fromage said:
Kind of an amazing feeling going from putting check balls in a valvebody to driving it around in an afternoon.
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Sure beat my record and I haven't had to do it from underneath like you have :beer:
 
Yes, not a great idea. The first time I used silicone grease to lube the O rings up, this time straight ATF and this time it almost seemed to work better. Not sure why. I pressure tested everything and it seemed fine.

One of the things I would like to do is add a spin-on trans filter up front near the cooler. Any recommendations? I have seen many people use a straight PH8A oil filter with good success. I cut apart the factory filter and it's not very good.
 
Fromage said:
...One of the things I would like to do is add a spin-on trans filter up front near the cooler. Any recommendations? I have seen many people use a straight PH8A oil filter with good success. I cut apart the factory filter and it's not very good.
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I added one to my Ford van that I purchased at a local hydraulic shop. I'll check to see if I can get you a part number.

My 2002 NPR came with an OE frame-mounted transmission filter. I originally thought it was a fuel filter until I traced the lines. I'll get you some info on that one also.
 
Update:

We have lockup.

Once I got it on the highway the truck seemed to run "different". Keep in mind I still don't have a tach, so it can be difficult to figure out what RPM the engine is running at, and since I have been into the transmission and the shifting has noticeably changed for the better, I figured it might have been something else.

It was easiest to tell at about 50 mph. In fourth, I could flare the RPMs by stepping on the accelerator, and upon releasing, they could come back down to the same point, exactly. I then came to a long uphill and held the throttle back, and it went up the hill at exactly the same RPM but the boost increased a huge amount. As soon as I depressed the accelerator any more, it would unlock and the RPMs would flare.

The engine runs a lot slower on the highway and it's really noticeable at lower speeds.

I'm going to be commuting with it for the rest of the week, we'll see if the mileage improves.

Edit - On the filter front, mine also had an external filter but the mount was badly corroded and broken. I think that the OEM trans pan filter is not designed to filter fine particles. After cutting one apart, I will be adding a filter ASAP. I think I am going to hide it behind the grille in the front.
 
Congratulations! Get a tach working to verify that lockup is working. Try a test light on the lockup solenoid to see if the TCM is commanding a lockup.

The filter on my NPR is a WIX 51622 and if plumbed between the front transmission line and the cooler. IIRC, that is the output from the transmission. On my the filter mount that I installed on my van there was a plug on the inlet side of the filter that I replaced with a pressure switch (5 psi if I recall correctly) that I wired to a light. If the filter were to plug up, the light should come on.

Here is a photo of the filter on the NPR:
ATF-Filter.webp
 
Hey, congrats!!! Welcome to the world of stable cruise RPMs, haha! You should see a marked improvement in fuel economy with the converter locking. On rural roads where the speed limit is 40 or 45, I find myself accelerating to 50 to lock the converter and then slowly coasting back down to 45 just to have the converter locked. (It locks around 48-50MPH indicated and unlocks at 43-44 indicated when throttle is being applied, unlocks around 40MPH indicated when no throttle applied)

My truck definitely did not have an external filter, nor do I have one installed or plans for one.
 
The drive in this morning was awesome. I barely have a toe on the accelerator and I can maintain 70. Instead of slowing down on uphills and requiring more throttle, it just lugs down and the boost comes up. I am finally experiencing torque rise. It now pulls hills better than my 2001 VW TDI.
 
Fromage said:
The drive in this morning was awesome. I barely have a toe on the accelerator and I can maintain 70. Instead of slowing down on uphills and requiring more throttle, it just lugs down and the boost comes up. I am finally experiencing torque rise. It now pulls hills better than my 2001 VW TDI.
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That's sounding a lot better!! More in line of what was expected from a nice diesel swap. I bet with that kind of driving your fuel economy is going to sky rocket.
 
Fromage said:
The drive in this morning was awesome. I barely have a toe on the accelerator and I can maintain 70. Instead of slowing down on uphills and requiring more throttle, it just lugs down and the boost comes up. I am finally experiencing torque rise. It now pulls hills better than my 2001 VW TDI.
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It sounds pretty awesome too! You passed me last week in traffic on the 5 and the truck had a really nice diesel rumble to it.
 
Hey, thanks! I keep seeing you on my drive home.

The truck's been running great. I installed a second battery and changed the glow plugs and it starts like a champ, all the way down to -25. It grumbles a bit but it always fires up. It is also a MONSTER for plowing snow. The trans with the bigger torque converter and lower 1st works great. I had one instance where I was plowing for about an hour at very low speeds (driveways etc) and the temp light came on, and after investigating the entire front grille was covered in ice and snow, so there was no airflow through the front of the truck. Since then I just clean the ice off and it works great. I got 250 miles out of the last tank, with a lot of plowing, on the 1FZ I would have gotten 150 or so...
 
So when SuperHatch changed out his injection pump for an earlier version with a mechanical governor, he sold me his old computer. It took a while for me to get it but I eventually swapped it into my truck to make sure it was good and sure enough, it is fine. So I pulled the cover off of mine and took some pictures to see if I could identify the PROM chip, to perhaps look into reflashing it.

Here are the pics.

IMG_9060.jpg


IMG_9061.jpg


IMG_9062.jpg


A few things I have noticed. First of all there are two large black chips, 80 pin, that look like they could be PROM. They have a very similar part number and look to be the same basic part, so I would bet that they are both PROMs.

IMG_9065.jpg


IMG_9066.jpg


IMG_9067.jpg


I also noted three adjustable potentiometers, identified as L1, L2 and L3. They are encased in a stainless shroud, but they can be adjusted.

IMG_9064.jpg


So, Dougal, any idea where to start? I guess I would need to socket both chips? I am curious as to what the pots do...
 
First step is to identify each potential chip. Googling the numbers on the top should get you some idea of whether they are a ROM chip or whatever. The ROM chips on my ECU's (I've done two, both Zexel, both Nissan) had factory stickers over the top of the chips.
In particular they had a 6 digit code followed by a dash and a four digit code with a 5 digit code underneath. I can see one of those.

Peel that sticker (mine came off reasonably easily) and see if you can identify the chip underneath.
 
any update, wondering if you have done any road driving and what the mileage was, 250 miles on a tank with alot of plowing is good..
 
Long overdue update...

Trans is fixed and the lockup working properly transformed the truck. It looks like I had a partially fried TCM that was causing some lockup issues and a replacement TCM fixed it. It had probably been that way since I swapped the truck.

I love this thing. What used to be a big hole between 3rd and 4th is now filled by 3rd lockup and the truck pulls great. It maxes out at 18 PSI of boost and I think the turbo is the restriction. Long term plan is to either do twins or a VGT setup.

I just bought a snap-on pulse adapter for timing it and will finally be able to really dial in the timing. Because of the electronic timing advance I have timed it by ear but I think it's still not perfect.
 
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Fromage said:
Long overdue update...

Trans is fixed and the lockup transformed the truck. It pulls like a train. What used to be a big hole between 3rd and 4th is now filled by 3rd lockup and the truck pulls great. It maxes out at 18 PSI of boost and I think the turbo is the restriction. Long term plan is to either do twins or a VGT setup.
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So what was the final solution to the lockup problem?
 
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