Ford A4LD Automatic Transmission Rebuild Project

I'll eventually work towards making this thread a detailed how to article but for now its just a log of what has been done and what I've learned along the way. If you have any tips or information to contribute, feel free, I'll add it to the how to article once it's done, I'm not claiming to be an expert after rebuilding a single transmission by any means.

Like many of you, I've always heard, "Automatic Transmission? Don't try to fix this yourself, take it to the pros!"

This is a different truck but when I was in college I took my daily driver to the pros twice. The first rebuild only lasted a year before I needed another rebuild. Of course the warranties are always a year from most shops. Each time it was over $2,000 to get a rebuild and I was with out my truck for a month.

I've been wrenching on cars for awhile and figured, how hard could it be? I love to learn and am always pushing myself to learn new things, hopefully I didn't push to far this time.

At the time of this writing I'm about 70% done, time to get this thread caught up!

Here are some over view shots of the project truck, it's a 1994 Ranger with over 250k miles. Eventually it will be bagged among other things but for now it needs some work to be drive able. It runs rough but more on the engine fixes later.

Transmission Symptoms
- No Forward Gears
- Reverse Only
- Pressure with in spec in all shift positions
- Fluid - To me it doesn't smell burnt but the fluid is pretty nasty

If you are trying to fix an automatic transmission your self and it's your first one, there are some great videos out there to get you started and I highly recommend getting a manual from ATSG or your factory service manual. I'm going to be as detailed as I can but I've found having multiple sources of information is helpful. Essentially this is like a giant puzzle.

The diagnosis procedure for No Forward is basically
- Check Fluid Level
- Check Shifter Cable
- Check Fluid quality and or replace filter
- Check Pressure in all shift positions
- Check Valve body and solenoid functionality
- Check Bands
- Check Forward Assembly (At this step you are basically looking at a rebuild if you haven't resolved the issue already)

If this was a later model, I'm sure there would be additional steps to check the computer

I just followed the procedure for the most part

First I checked the fluid level, seemed high so I removed some fluid using a siphon.
The shifter cable seemed to be fine, I confirmed it was changing the position as expected on the transmission.

The next step was to check the pressure. One thing I wish I would have done was to get a gauge that could read higher pressure but here are some pics of hooking it up to the test port.So far with in spec.

In the end I knew it was going to probably need a rebuild but couldn't help but hope that I would find a simple fix. I scored a deal on a disassembled A4LD for only $85! I knew I might need the extra parts and this I couldn't pass up. I was inspecting the valve body when I found this deal.

It's hard to tell from the pictures but the fluid is really nasty with a lot of grit. A lot of the valves in the valve body were actually sticking. I really thought I may be looking at a plugged filter and sticking valve body so that was my next step.

Here are a couple pictures from that step, I ended up using the donor valve body since the fluid in it was much much cleaner.

Picked up this trick from another member, using the pump to drain the fluid out of the pan makes it a lot easier! I just used a clear hose and a hose clamp to attach it to the radiator port and ran the truck just enough to drain most of the fluid.

Also here is a picture from underneath.

There is an example of how much cleaner the donor valve body fluid was.

On a side note, I ended up drilling holes in some of the plugs thinking it would be easy to get replacements cheap, well it wasn't, thankfully I have another valve body. If you know a source to buy just the plugs please let me know!

While the valve body was out I also checked the solenoids, one was bad so I replaced it. Here are some pics from doing a simple test. Checking for resistance and also functionality.

more photos