Build "The Milk Truck" FJ45 Preservation Sorta

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This transmission issue has certainly taken the wind out of my sail. Considering I purchased two lower mileage transmissions just find out neither is good enough to run as they are is disappointing. I have been researching the issues, and am considering a new Nomad valve body from Wholesale Automatics might solve this issue unless it is a clutch disk problem. Supposedly the currently installed transmission had 106k on it when it was pulled for a drivetrain swap and had been well maintained. I want to believe the disc packs in the transmission are in good shape and the issue may just be that it had been sitting for a few years before I ran it again in which time something got gummed up.

I sent Wholesale Automatics a message to see what they would recommend given my symptoms.

I have a third A750e transmission for a 2x4 that I had driven before it was parted out. I believe the VB are the same and I have no use for it, so considering pulling the Valve body out to swap it in to see if there are any changes. Kind of seems like a waist of that transmission though. Certainly the cheapest test and probably what I will try even if I order a Nomad VB considering they have a 5 week build period.
 
I have never been into your particular transmission. Saying that, I have built a lot of different automatics. A couple things in common that I would suspect in ONE low pressure clutch is the clutch piston seal, a shaft seal that affects that clutch or the control valve spool/spring for that clutch.

Maybe find which valve in the valve body controls that clutch and see if it moves freely or maybe it has a weak spring.

Doesn't sound like the clutch itself.....yet. since no material in the pan. Nothing else is low pressure so pump seems to be doing it's job.

Anyway, I wish you luck with it. Very frustrating and disappointing.
 
aztoyman said:
I have never been into your particular transmission. Saying that, I have built a lot of different automatics. A couple things in common that I would suspect in ONE low pressure clutch is the clutch piston seal, a shaft seal that affects that clutch or the control valve spool/spring for that clutch.

Maybe find which valve in the valve body controls that clutch and see if it moves freely or maybe it has a weak spring.

Doesn't sound like the clutch itself.....yet. since no material in the pan. Nothing else is low pressure so pump seems to be doing it's job.

Anyway, I wish you luck with it. Very frustrating and disappointing.
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Thank you I appreciate the tips and suggestions.
 
I took break from the 45 for a week but got back to it today. I swapped in another Valve body from another a750 but I got the same test results. I don’t think the Valve body is the problem. I think the next option is to test the shift solenoids.

If it is not a bad solenoid I may just look into buying a rebuilt transmission. If I have buy a rebuilt transmission can anyone recommend a good supplier for them?
 
I appreciate the ideas and help please keep them coming. I am learning as I go here and I suppose it is possible that there is some sort of issue in the wiring but I am not convinced yet that is the issue. In my google research I found my issue described in the attached article. It says that the SLT Solenoid, which is the Line Pressure Control Solenoid, can cause the two issues I am having. The SLT solenoid seems like it could be the cause of the poor drive pressure test and the hard shift into drive.

I need to figure out how to bench test the SLT Solenoid to test it before I order replacement parts. If the solenoids all pass the bench test, I will look at wiring next.
 

Attachments

I tested the the SLT solenoid and it worked but seemed sluggish in comparison to the one from the 4runner A750 I took the valve body out of, so I swapped in the 4runner solenoid. The other solenoids functioned as best I could tell as they should. I put it all back together an ran the hydraulic test again. This time the gauge responds erratically bouncing around. It spikes into the acceptable psi range on all tests but it was much more stable on prior tests.

When shifting into drive it still shifts hard but not as bad as before. I opted to take it for a drive. I ran it through the gears it shifts smoothly when accelerating and doesn’t slip or search for gears like the last transmission did.

There is still an unsettling noise that sounds like the tips of the engine fan barely brushing something as it turns. I removed the fan shroud to eliminate that as an option but the noise is still there. I looked at the drive shafts and there is nothing close they could be contacting.

Really sounds like it is coming out of the transmission or tcase area. I am tired of thinking about it. I am going to set the 45 aside for a bit and see about finishing the 80 series drivetrain swap.

If it wasn’t for rotating noise I am hearing and the clunky shift into drive, I would say the 45 drives great! It acetates and drives really well.
 
sorry for your transmission woes, never a fun thing to diagnose.
 
I opened it up again an re-tested the solenoids to make sure I tested them correctly. I also tested the same solenoids from the other transmission I had and both all tested per spec. and passed the function test. I suppose the o-rings could be leaking inside causing my problem but I am reluctant just throw money at new parts.

I put it back together but looped the cooler lines together removing the cooler from the system. I was wandering if the cooler built into the radiator or fittings I used could be restricting the flow. After topping the fluid off and warming it up I ran the hydraulic test again and found the test similar but the needle on the gauge was spiking at the high end of the spec. (Drive/stall test) but it quickly dropped off below spec.

The test I am running is from a FJ Cruiser manual for the a750. Does anyone have a manual for a 2003-2006 Land Cruiser to compare the test. Could the test range be different?
This is what I am following.
IMG_7995.webp


For the most recent test I removed the cooler from the system but I would like to get another opinion on the fittings I used for the cooler. I am using these radium AN6 fittings that are kind like a banjo fitting.
IMG_7993.webp

I am using these for their low profile due the tight space at the bottom of the radiator. I am also using an6 braided hose to connect the cooler to the hard lines which are 3/8, the an6 fittings measure 5/16. Could either the fittings or an6 hose be contributing to my issues?

In considered the wiring I plan to reach out to the guy that built the harness. He wired the transmission and engine to be stand alone. All I did to wire the transmission was wire the shifter up but I only had to wire the safety switch, 4th, and 2nd. Maybe the guy that built the harness can help if there is a possible or issue there.

I’m am also realizing that what I am calling a hard shift into Drive only happens when it is put into gear. The loading could actually be an issue with the transfer case turning when put into gear when it loads. It is very slight when when put in Reverse and significantly more when put into Drive.

I’m considering having the first transmission rebuilt and the transfercase, so I would know what I starting with. I need to eliminate everything else first.
 
You certainly seem to be approaching this in a logical manor. I don't blame you, especially with the cost of everything. You're going to know your $hit when you're done. Smart move to check with the guy that built the harness. Hopefully after all this frustration it's something simple.

I'd have to agree with your test to eliminate the cooler circuit to check the fitting restrictions or lack of. I'm not sure the cooler circuit is relevant to the control circuit but worth checking.

Sorry I have nothing to offer other than I'm rooting for you and good luck.
 
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I purchased a Land Cruiser specific A750F manual on Ebay. Hoping it will shed some light on my issue.
 
This may come as a surprise but I am just going to throw it out there for those who have been following this build. I am thinking about selling The Milk Truck. I love the truck and know it will be a lot of fun as soon as I feel better about the transmission.

I have been thinking about it since July after spending a full 3 weeks with family traveling I have come to the conclusion I would be fine selling it. I am not in any kind of rush to sell it and I don’t need to. I am just open to it and not even sure what it would take to get me to let it go. I will keep tinkering with it and fine tunning things as long as I still have it.

I don’t intend for this to be a for sale thread, so if anyone is seriously interested in it you are welcome to send me a message and we can go from there.
 
Dennis, sorry to read about your transmission issues. The 750s are so bulletproof, I have to agree with the others that its very unlikely to get two bad ones. There are so many electronics in them that it could be a number of sensors or solenoids that aren't happy. Unfortunately, it will make it that much harder to diagnose having the harness wired as stand alone and not in OEM form. It's a tough call on what would be easier between tearing into the harness or swapping in or rebuilding your transmission. This is definitely one of those times it helps to have a completely stock form of the vehicle available for comparing readings with the project vehicle.

I completely understand what you mean about selling. I think the majority of the fun is building these things. I certainly have more fun building them than driving them. My only recommendation is that you don't sell it while you're frustrated with it. I think you owe it to yourself it get it driving correctly before selling. You need to ask yourself if you'd be upset if you sold it and within a few weeks saw somebody else had it up and running correctly like you wanted.

You're pretty close to the finish line. The last 10% is definitely the hardest part.
 
@UZJ40 I am not frustrated by the transmission issue, and not the reason I am thinking I would sell it. I agree with you and others, I doubt I got 2 bad transmissions and I mixed the parts in from a known good third transmission. I am thinking there must be something else. I have never dealt with an Automatic transmission issue like this before, so I am forced to take it slow in hopes of not destroying the second one. I don’t want to throw parts at it and hope it works. The issue is just forcing me to learn more about it and take my time. At this point the hard or fun part of this build is done, I just have to sort through this issue.

Why am open to selling it. I have 4 vehicles and two of them are project Land Cruisers. I technically started acquiring parts to build a 45 back in 2016. My goal was to learn some new skills while building a fun FJ45 trail rig. This project has been in the making for 8 years. My wife doesn’t really care for it and has no interest in taking trail rides in it. She has liked the various 80s we have had and I more recently acquired an 80 series I want to build and have been slowly putting together. I have thought for some time that I can only keep one. The 45 is obviously the coolest but the 80 is the most practical if I want to spend time with my wife. It just makes more sense to keep the 80 for my future adventures. I will definitely miss the 45 if it sells.

I really enjoyed the challenge of building the 45 and after I had it together with some miles on it in July I felt like my climb to the mountain top was complete. Sure I have a few things to sort out but the hard stuff is behind me. It has been a challenge to build but over the 8 year process things changed and I am fine taking a different path forward.

I did reach out to the guy that built the harness and told him what I am dealing with. I am just waiting to hear back from him.
 
I have been poking at the transmission issue a little bit. I am getting trouble code P0705 Trans Range Sensor Circuit/the Neutral Safety switch. I have swapped out the switch with another used one I had and confirmed the plug and contacts are all in good condition but both switches produce the same code. I have run a test in each gear and found that the reverse gear does not create a trouble code but every other position triggers the P0705 code. I think the next step is to test continuity and voltage to the ECU. I am getting concerned that the issue could be in the ECU if the wiring checks out.

I did talk to the guy that built the harness he doesn't believe the issue is in the harness. I may end up ordering a new neutral safety switch to at best confirm the issue is most likely in the harness or ecu.

It was also suggested that I swap out the fluid for Toyota T-IV Fluid. The transmission fluid I installed first was synthetic Amsoil that was compatible/equivalent to T-IV. When I swapped in the replacement transmission I use Valvoline Maxlife also T-IV equivalent. I really don't think the fluid is the issue but I am going to do a complete transmission flush and fill it up the the OEM fluid just eliminate it.
 
Tank5 said:
I have been poking at the transmission issue a little bit. I am getting trouble code P0705 Trans Range Sensor Circuit/the Neutral Safety switch. I have swapped out the switch with another used one I had and confirmed the plug and contacts are all in good condition but both switches produce the same code. I have run a test in each gear and found that the reverse gear does not create a trouble code but every other position triggers the P0705 code. I think the next step is to test continuity and voltage to the ECU. I am getting concerned that the issue could be in the ECU if the wiring checks out.

I did talk to the guy that built the harness he doesn't believe the issue is in the harness. I may end up ordering a new neutral safety switch to at best confirm the issue is most likely in the harness or ecu.

It was also suggested that I swap out the fluid for Toyota T-IV Fluid. The transmission fluid I installed first was synthetic Amsoil that was compatible/equivalent to T-IV. When I swapped in the replacement transmission I use Valvoline Maxlife also T-IV equivalent. I really don't think the fluid is the issue but I am going to do a complete transmission flush and fill it up the the OEM fluid just eliminate it.
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Worst case on the ecu would be needing a new ecu and new key? Might be a simple test after the neutral safety switch and before swapping out the fluid. Just thoughts
 
@Bripars40
The harness builder is who is telling me the fluid is the reason for the pressure issue. He is also who will have to reprogram the new ecu if needed. I feel like I need to eliminate all possibilities before pulling the harness and ecu to ship it back for troubleshooting or reprogramming if I cannot figure it out myself.
 
Well I’m my worst enemy in this case. It was an electrical issue and it was of my own doing. I had wired the reverse lights using an existing relay circuit from the 80 harness. Turns out that circuit was constantly powering the reverse pin no matter what gear it was shifted into and causing the issue. I pulled the relay I wired for the reverse lights and the error code is gone and the stall pressure test is where it should be. It shifts smoothly into D too!

I will still need to pull the dash harness to rewire the reverse lights but at least I sorted it out. I have been into the oil pan so much I am going to drop it one last time replace the filter and gasket again fill and flush with new fluid.

It should be good to go after that.
 
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