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How to: A4LD transmission rebuild diary

Prefix for threads which are instructional.
Sure no problem on the documentation. I dont remember if you sent me a number or not- e-mail me the number and a time- Ill be in and out all day waiting for word back on some houses I bid on, but if I get the info this afternoon, I can do it this evening.

From you post you said from bell to center support and then you were going to work on the govenor side. Maybe Im not understanding you, but before you can work on the govenor side you have to remove the CS, and the intermediate and rev assemblies.
When you get the case clean- check the rear of the case where the rev thrust washer wears on the case. Be interested to see a pic of that area on yours.

I agree on the sonnax parts- I was impressed with their replacement boost valve.

I also think that every bushing needs to be replaced in a rebuild.

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Steve VB wrote

I also think that every bushing needs to be replaced in a rebuild.
Steve I fully agree. If we're going to "rebuild" to a high standard we should replace any significant wearing part, or be prepared to justify why we didn't. I have the bushings and plan to replace all of em.

As for the governor, you can work on it with the shaft in place, as you might with it in the car. Not resleeve it or anything, but at least get at it. But you are right overall. (Your knowledge is based on "being there" in your rebuild and is appreciated!)

Anyway I decided to remove the rest of the case internal components, so will be posting pictures later tonight. Had a little surprise I found - be fun to share it...incipient failure...

Nude tranny pictures; does that mean they're "X" rated? :D .....OK, bad joke.

You invited opinions on the Merc V ATF earlier;
It's actually a semi-synth formula and I think Ford went to it for cooler running and to extend the clutch life. (It has more friction modifiers and is more "slippery") It also helps with TC "shudder", which late model Fords are plagued with. The sprial cut in the discs probably aids in keeping the lube film uniform along the disc face. Any xR55E parts that will fit would probably be beneficial, and I'd use the Merc V with the xR55E clutches.

Just my two cents, and I can't wait for more pics. Good writeup!:)

Thaks for the input! That's along the lines of what I thought.... wonder if I use 5R55 frictions in one place if I ought to use them throughout? and the TC ? Does it need to be 5R? Do they vary material to the fluid? I've never experienced shudder, but a stronger OD bore return spring (planned) should help that problem I think. (Sonnax again... I am appreciating them more and more).

Mercon vs. Mercon V

I found this link ATF Specifications which in turn has links to the specs for both Mercon and Mercon V.

Also, there is this thread where we were discussing it and I posted a TSB on applications which require Mercon vs. those which require Mercon V Mercon vs Mercon V

I'm attaching the chart for the TSB, but the quality isn't that great.

Excellent thread by the way :chug:


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Great ! Thanks Dogfriend. Tha was what I hoping this thread could be, a collaboration - to the ultimate rebuild.

The chart came out pretty bad. If you really need the info, email me and I will send a PDF copy so you can zoom in and read it.

The basic info is that Mercon V was only used for certain applications starting in 97. That was the same year they introduced the 5R55E. They list some 4R44E applications (Ranger,Aerostar?) that also use Mercon V starting in 97.

Well I figured that if push came to shove I could use AMSOIL synthetic.... and cover all my bases.


I wanted to use the C-4 intermediate band... thought it would fit (NOT) but here is why I wanted to use it...

The A4LD band is rubber banded to shape, it's flexible...


Similar size.... not easy to see but the C-4 band is cast iron.... much sturdier...

Not to make too much of it.... but look see how much sturdier the C-4 is!

So... a worthy goal... frustrated.... dang. Now you know why I chased it!



Ok, you heard me wax enthusiastic about these guys. Never heard of 'em a while ago, but now I know a littl bit about them.... amazing thin needle bearings designed to take the place of thrust washers.... bearings instead of oiled surfaces.... reminds me of the roller cams on some 4.0 engines.... less friction and sooo thin... is a Torrington and the washer it replaces


As for thickness?...


Or better yet look here:


The Torrington bearing is nearly as thin as the solid metal "thrust" washer !!! Incredible. A MUST on rebuilds on this trannie. In my humble opinion.


Ok we'll finish the teardown today. Let's start back inside the case, where we left off at the center support.
The support is held in place by a lage snap ring and secured by a screw. Pry it loose from the case on one end using a screwdriver

then grasp the ring and pull it upward, the snap ring will peel itself out

The bolt is held by a nut inside the case.

The bolt is an allen head, located in the valve body


It' easy to remove using a 5mm allen head socket

Once it's out the center support can be wiggled loose and brought up out of the case

and we can see now the top of the intermediate drum underneath

On top of the intermediate drum is a washer (or a bearing in later applications (93 on). We'll use a bearing.

This washer looked a little scored - not bad, but like metal particles were in the fluid lubricating it

Now we can get at the intermediate band - it's just like before, remove the struts and wriggle the band up and out. It's tight space and this is a little tricky - I dropped a strut down inside and had to retreve it later

The drum assembly comes out as a "package", and it's slightly heavy


Now we see the forward ring gear and the bearing sitting on top of it. It is a torrington, though slightly thicker - it' #6

Here's a side view (bad pic I apologize)

Ring gear comes right out


On the back there is another bearing (#7) - it's the innermost outer gray ring (does THAT make sense?) - and yes - another bushing to be inspected or replaced (replaced on our rebuild - all bushings)


This exposes the forward planet - which comes right out
(notice that is a steel 6 pinion - standard on 4.0's)

On cursory exam this one looks good


Now we are down to the "input shell" this is where it starts to get interesting

When I remove it, there is a thrust washer on the back, number 8 -
see the 3 tabbed washer sitting on the rear ?

When I turn it over I find this - bearing material shredded and largely gone - you can even see a sliver of it off one edge


Here's another picture of it nice huh ?


Look at the mating bearing surface on the back of the shell - yuck [as it turns out, a steel washer was left out of this rebuild - hence this failure - I'll point it out on the rebuild]

Since I am down to it, I'll remove the reverse band - seems almost like an interruption of discovery..

We're looking at the reverse planet now inside the ring gear housing - on 4.0 models there is no snap ring retaining it


When I inspected it, I found this - galled points, and a hunk of a tooth just sitting there...and a bent support web...ow.


Look at the backside - this is not normal... all chewed up

Caused me to reinspect the sun gear in the input shell - the retaining ring looks like it is loose and was chewing into the planet - note the teeth - damaged - replace time.


Well, back in the case, you just have to suspect what's left isn't pretty... here is the ring gear for the planetary... I haven't pulled the output shaft yet...


4.0 engine use an oil dam, it's next up to come out

Then you are at the ring gear and it's washers, front and back.... my pictures do not do it justice but let's just say that the front bearing is TOAST

Now the snap ring... FORD says not to reuse it....

with the snap ring out, the ring gear can come out...


as you an see, there's large thrust washer on the back (which was more or less ok)


The one inside was another matter - bad picture but use your imagination -Ugly damage

Last thing out is the reverse drum. It looks okay overall, but can you see the HUNKS of metal in it ? Whoa!


Someone asked for a peek at the back end, behind the bearing race - not a great shot but best can do...the wave washer is a problem child - this will get a special treatment in our rebuild.. this "wave washer is also reputed to be the genesis of the governor problems


I've flipped the transmission around, and removed the bolts holding the extension housing in place, I'm taking it off here

That clearly exposes the governor - which comes off with a couple bolts (more on the governor to follow later in this article)


Here's the underside showing the fluid passages

And now I can pull the output shaft free of the transmission

Next out is the Governor oil collector. This can be a trouble spot for it has steel rings riding in an aluminum bore - we will resleeve his bore to steel..

This one looks good though - But try an old machinist's trick... a fingernail can detect incredibly small variations on a flat surface.. I "nailed" this one and it was good... you can see the resting place for the steel rings though...will sleeve it anyway

The bronzy thing is the back most washer... #11. This one looked pretty good.... minor scoring fom metal but overall not too bad. I'd not - on a "bulletproof" rebuild, ever reuse any washer, and this one will get replaced


Ok now we remove the last bits.. the modulator is held in place by a Y clip/clamp bolted to the case... this bolt also holds the heatshield. Do not lose this - FORD wants $19 for it!! Yes for a double headed BOLT !


Showing the clip/clamp off

If you do NOT want to drop a part, ANY part, this would be number one NEVER TO LOSE! The Modulator pin...

It easily falls out. SAVE it. Hell...CHERISH IT !

Next up the neutral/reverse switch.... Ford has a special tool, but a 19mm thinwall deep socket will work, mine was not hard to dislodge.....
Here's the two tools.... silver is the deep thinwall

the aftermarket fits, though with a lot of points....


I'll admit the FORD one is a better fit, but essential ? no...


Ok what's left are inside levers and the like... have to take the case (now VERY LIGHT) off the stand to get those out.

Here is the inside view of the main shaft - nut loosened, yu can se the retaining pin in the middle right edge of the picture - this is a PITA to get out...

Here's it, pointed out... I tried to remove it without success, so I sprung for a special tool... shuld have it in a couple days - for $15 it seemed worthwhile, we'll see..


I will add pix of that when I get it, just to be complete, and then the next thread will be component disassembly and evaluation - and case machining. Feel free to chime in with ideas - my newest one is C-6 seals in some places! (I know I never give up).


ps. if you think this thread is worthwhile let me know - o if you need to see something I ovelooked - it is a LOT of work to do thisa, and sometimes I wonder how many people are interested, or may benefit.

pps. For those awaiting governor info, that's coming next (that's for those of you with pre '95 Explorers - '95 and up do not have either a governor or a vacuum modulator, those functions now being handled electronically).

I've talked to many mechanics and the thrust washers around the center support are not really a source of weakness in these trannies.

Are the torrington bearings good to have? SURE.

Are they necessary when rebuilding an A4ld? No.. if you have the older style center support, just get new thrust washers (#3 and #4 I think) for it and call it good. My thrust washers around my center support showed very very little sign of wear after 85k miles.

Originally posted by slag
I've talked to many mechanics and the thrust washers around the center support are not really a source of weakness in these trannies.

Are the torrington bearings good to have? SURE.

Are they necessary when rebuilding an A4ld? No.. if you have the older style center support, just get new thrust washers (#3 and #4 I think) for it and call it good. My thrust washers around my center support showed very very little sign of wear after 85k miles.

IF anyone takes this route and keeps the thrust washers then YOU SHOULD MAKE THE OIL HOLE MODIFICATION TO THE CENTER SUPPORT- if it hasnt been done. There were identified oiling problems to the #4 washer, and before the factory replaced the washer with the #5 bearing the fix was to drill the center support to add a lube hole for the bearing.

Good points, both. The idea on this rebuild is to go "all out" - not saying that some of the avenues chosen for this rebuild are "essential". But as we go along these types of comments are most welcome, as with the responses they bring as well. Thanks guys!

Note: This thread will soon be ended an a new one started on evaluating component parts prior to rebuild. Old threads (like this one) will be linked.

i find this thread very helpful when my tranny goes out although not the same it is very helpful to know what is involved so i can hopefully rebuild mine

the guts of the A4LD are the same as the 4R55 and closely related to the 5R55, so they are more then just cousins under the skin. The big change came in electronic shift control. 5 solenoids in place of 2. Guts, same, or mostly. Valve body? WAY different... Governor ? Gone - in 1995 - in place of electronic speed control monitoring on the center support.

Chris, this thread is excellent. You almost have me convinced that I could do mine myself.

A little postscript... that nasty damage behind the rear planetary inside the ring gear? It appears that by 2000 FORD had replaced that thrust washer with a torrington bearing - I am exploring THAT possible upgrade too.

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I am saving this space for a short discussion about snap rings. I am more and more believing that SNAP rings, of all kinds, are somethnig that you should NOT re-use. I have some pix to illustrate this, and I'll add them as soon as I get time.