A4LD Valve Body Rebuild Diary | Page 11 | Ford Explorer Forums - Serious Explorations

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A4LD Valve Body Rebuild Diary

Well today I got to it. I had prepared a valve block last week, but I wasn't too happy with it so decided to just sort the fitted one.

Initially I tried to pump out the oil but only managed a pint before it gave up, so it was back to the factory method of letting it pour out of the sump after loosening the bolts. Quite messy and of course I ended up with oil all over the floor!

After dropping the sump, I checked the solenoid again for activity, but not a murmur although it was pulling current. Unfortunately, the solenoid cannot be changed without stripping the valve block, so that's what I had to do. The block is held in with 25 assorted length bolts so takes a while to remove.

Now the brain surgery...

Once on the bench, three Torx bolts are removed to gain access and the gasket peeled away, thankfully in one piece. That revealed all the valves etc. There are six checkballs, two pucks and some retainers that all fall out at this point if you are not paying attention.
Next the valve body was drilled as per the Transgo instructions. I am not totally sure what difference it makes though! Once done the valve body was solvent cleaned and then the other modifications carried out to various valves. That went fairly well apart from having some parts that were totally different to the manual or supplied instructions. I was unable to remove the TCC lockup valves, but cleaned and exercised them to check. Initally they were stuck. There is a modified spring to install, but as I couldn't get the valve out, it had to stay original. Shame really as that was the area of concern.

Once complete, the new gasket was fitted and the intermediate plate fitted with the three Torx screws. In the manual is says there are only two! I nipped them up and intended to torque them next.
The valve block was offered up and some bolts installed. Then I realised that there are four different sizes so had to take them all out again to assess what went where.
Once done, I nipped up the valve block and checked the manual for the torque setting. Then it dawned on me that I had forgotten to torque up the three Torx bolts, so back out with the valve block AGAIN. FFS!
Next was the reverse/first servo. Mods to that required dismantling by pressing in the vice. A wire clip is removed and an internal spring gets replaced. For some reason, the instructions say not to re-install the clip, so I followed that rather than my instinct.
There was a note on the instructions about not forgetting the return spring. WHAT return spring? I couldn't remember seeing one so checked the workshop manual. That also called for a return spring, so another hunt around followed by stripping the servo from a C3 which revealed no spring IS fitted. So that went back in with new gaskets.

Once everything was re-installed a quick double check of the work and torque settings completed, I installed the sump. For some reason, I was missing four bolts that I had to rob from another box. Once I had done that, I found the four bolts of course! I had drained over a gallon of ATF so I put a similar quantity back in and ran it up to temperature.

Cycling through the gears, I had a loud rattling in all forward gears. Checking the levels showed it was still low, so topped up again. Sadly, no change so up in the air again, to find that the centre silencer was rattling on the lift crossbar.

Once happy with the operation I took it off the lift and cleared up. I was unable to check the TCC lockup as the roads were full of Sunday drivers, even the bypass was running too slowly to do any testing. The general operation felt nice, maybe psychological though. It changed up nicely and changed down correctly. Flooring it kept it in low gear until about 4K RPM so that's all OK. I managed to get to about 40MPH briefly and I think I saw a lockup, but not sure. Further testing to do now.

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One issue that I didn't resolve was a whine in first gear. It ceases as soon as it changes up and re-appears when it changes down again. I am not sure what could be causing it as the pump would surely whine all the time?

Well it never rains!

The TCC lockup still did nothing so had the sump off again. The solenoid read 30r and I tested it with a car battery feed which proved that it was operating. Then I checked with the car wiring and got nothing. Testing at the socket showed that there was a dead short across the socket. I checked with an endoscope and there was nothing in the socket that shouldn't be. Cleaning it didn't help either. So next thing is to see if the short will burn out with a car battery. Well it all got hot and there was a flash from inside the socket. Still dead short though, despite leaving the power on. I imagine that the protection diode lives in the socket and it was that which had gone s/c?

As I am feeding it 12V switched rather than ground switched like an ECU, I decided to link one side of the solenoid to deck and feed out the other side through the socket, so did that and reassembled. I powered it up to test and heard it clicking, I also got bitten by the back EMF when disconnected. ;-)

Then I had to replace some burnt wiring and tidy up. I also added a temperature sender in the pressure test blank position. That will be useful for the ECU I am building. Naturally whilst doing all this outside, the heavens opened. I got everything sorted and went to start the engine which then died and didn't restart. That was due to the fuse that blew as a result of the short, so another job to do in the rain!

Sunday drivers still out in force, but I was able to do a quick test and that showed it still didn't work. So two days wasted so far. Looks like I should just find a rebuilt box, rather than keep messing about with this one.

When I stripped the valve block from the gearbox, I noticed some differences with it, in particular, this set:


This picture is from the first valve block I did, but in this other one one, there was a different part (the large one with the scuffs on it). The part has only one hole in the side rather than the three and there was no internal valve nor spring installed. I put it back as was and I am just wondering whether this has been "got at" in the past and parts are missing? Apologies that I don't have photos of the installed items.

I am going to have one more go at the valve block and it would be handy to have a bit more information to save wasting my time again!

Do you have the NTSG manual yet for the A4LD? Those are the cheapest to buy and based on the big Ford shop manuals. They have almost all of the same pictures, and plenty of detail, invaluable for identifying parts etc.

Progress has been made! I was referred to a company who specialises in valve bodies and they had a man who used to work on A4LD boxes. He was very helpful with advice, so much so that I ordered a refurbished valve block from him. It was rebuilt in the day and sent out for me by pre- 12AM delivery. A new solenoid and sump gasket was included and I was given a decent discount. The replacement job was started at 09:45 and finished by 12:00 which included changing an O ring on the speedo drive and attending to an exhaust leak.

IT WORKS! So there was definitely something up with the one I took out. It will be interesting to see if I can find out what it was now. I am most grateful for everyones help. The only irritation now is the whine in first gear, but I can live with that for a bit. ;-)

Whew, thanks.

Man am I glad I triple checked everything with the Transgo schematic and your pictures lol. I realized the one bore that it says DONT REMOVE? Yea, somehow the L retainer got lost. Figures. While I'm waiting for these to show up, do you know where that little TCC filter goes? Can't seem to locate it anywhere.

Ah have, finally. I'm a little concerned as to why I never had one. There also seems to be a spring wedged in the passages on the trans side that I've never seen mentioned but whatever right? I was also kinda stoked that my separator plate was already the correct size on 99% of the holes. This truck is just an oddball

Case spring:


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You're amazing bro. Where did you find all this stuff? I Googled for hours trying to figure out why that was in there and where the tcc filter went lol. Thank you immensely. Hopefully T.P. USA gets my retainers to me for Saturday delivery....

Good morning guys. Just wanted to leave an update on the outcome of the VB upgrade. It seems as though reverse doesn't fully engage without giving some throttle, once it engages it's fine and 4th takes its sweet ass time engaging. Following the transgo instructions I replaced the reverse servo spring inside, but after doing some late night go googling I've seen where some people have left the large outer spring out. These were not in my instructions but im.wondering if that's my problem there. As for 4th, I have no idea. I checked every valve before assembly and they all move well, however now I'm doubting myself on not drilling the pucks out larger. TECHNICALLY, all gears work just not the way they should be.

Damn it lol. I've done a lot of stuff in my short life and own a lot of tools, but testing transmissions isn't on the resume'. Something told me to leave it alone