4R70W Rebuild Diary - Part 11 - Reverse Clutch

[Glacier991]

The reverse clutch in this transmission sees duty when you select reverse gear. On top of it sits the "mechanical diode" that splines into the intermediate clutch. It comes in most cases as a 3 plate clutch, but can be converted into 4 plates.

I cannot see the necessity for a 4 plate clutch here.... Unless you are pulling things in reverse. Extra plates mean extra holding power but also EXTRA heat.... and unless I can justify the extra plates, well... I'm not going for it. This will be a 3 plate build.

This clutch has some things this kid has never seen before. A wave snap ring for example! Let's put one together.

We start with a new drum.... FORD Part No. F8AZ-7D044-AA Price $77.70

(pic)

Each drum of course needs a piston. FORD Part No. F2TZ-7D0402-A $28.77
Here is the piston, pretty plain Jane. Notice a check ball. If you are reusing make sure this is clean and rattles.

We need 2 seals... like most pistons, inner and outer. Here they are

We add the outer...

then the inner

and here it is all assembled.

Now these seals are kind of unique, in that they are NOT lip seals! But square cut - look

Now I know I often harp about using the seal protectors when assembling lip seal clutches. Well the old black AOD seal protectors won't work on this one. The new blue ones do... but ya know what? you can't turn a square cut seal.... so I lubed the drum.... (I use vaseline as my trans assembly lube... it's cheap and effective) first the outer periphery of the piston "pocket" in the drum

and then the "snout"...

and the piston slid right in... without protectors. Here is it seated in the bottom of the drum.

Now while there are some pistons I would never dare try and install without a protctor.... this ain't one of them. Still, use care.

Next we add an odd ring. This serves a place for the piston "spring" or "Bellville return spring" or .. to ride.... FORD part No EQAZ-7B070-A ($5.92!) Here is it being placed

and in place

Next up is the "Bellville return spring" or .. FORD part no F2TZ-7B066-B ($13.38) here it is

and here it is installed.... fingers point down and ride on the previous "ring" part.

What holds all this in place is a snap ring.... here it is from above

but wait! Look at this thing! A waved snap ring! Here are a couple of views.

In order to get it in.... we need to compress the wave plate. The AOD toolkit has a tool for this... here it is:

And here it is in place on the bellville spring

To use this tool to compress this plate, you use the clutch spring tool, but use it backwards! Installed so:

another view

and on the other side....

You tighten the nut until the spring groove is clear. The then trick is to get the wave retainer in place... a minor task but a task none the less. Once you do your best to get it in, there will be a couple places that do not compress enough to go into the grooves. I used a small pin punch and a small hammer to angle punch the spring down so it would fit, worked pretty well actually.... here is the set up

You can see the retainer is captured under the grooves. MAKE SURE THIS IS SEATED COMLETELY.

I air checked this assembly and it worked fine.

Here is the completed piston and bellville return spring and wave retainer...

So time for steels and frictions.

I had some new steels (2 to be exact) and scuffed them with carbide paper. I picked up 3 frictions from Axiom (www.aceomatic.com) for about $1.95 each... here is the FORD part No...

Thickness?

Out of curiosity I also measured the old ones from another clutch I had around...

Same. Now in fairness I do not know mow many miles the used tranny this came from had on it, or how long since rebuild, but this "kind of" illustrates my point about friction wear. Ain't much in a healthy tranny. Here is the old on top of the new...

The new has not been soaked in ATF yet so it will darken up some.

There is a front and back pressure plate. The front (first in) is the thick one.. Here is the front plate...

The side you see goes in DOWN.
Here it is in... smooth side up for the friction to ride against

on top goes a friction, soaked for 30 mins in ATF

then a steel...

in place awaiting friction #2

You add the frictions and steels, and finish with the last pressure plate flat side down onto the last friction, add a retaining ring and your clutch is together

Can you count the frictions? (Hint: there are three)

Another view

Now actually, the clearance on this pack you COULD measure with a feeler gauge.... unlike the forward clutch in this transmission. But I wanted to try out a new toy... a digital readout indicator.... so here is the measurement process using a dial (or in this case, digital) indicator....

We start by setting a zero or reference, in my case it moved a little so was .001

Then we pry up on the clutch plate/steel pack....

The result is around .046. I repeated this a few times and the results were about + or - .0015. Proper clearance ? 0.040 to 0.060... so we're good.

(btw that nifty little digital indicator was $20.)

Okay... reverse clutch is all together. The next post?

Stay tuned.... the "mechanical Diode' and the "Spiral Ring" of Death prevention.

[You just viewed two evening's worth of work... amazing how much time this takes.]

 

[Glacier991]

MECHANICAL DIODE and the SONNAX SPIRAL RING RETAINER


[I need to vent... like an idiot I nearly had this thread complete but had not stopped to save it... I had a puter glitch that caused me to be logged off and lost an HOUR of work here!! GRRRRR. Dumb me!] :fire:

The earlier versions of the AOD and AODE and even the 4R70W used a roller one way clutch for the intermediate clutch connection up until the mid 90's. It was a weak point in this transmission and FORD addressed it by creating what they called the "mechanical diode". While I find the name wierd, it did solve the problem. It comes from the factory as a single assembly that you add onto the lugs on the top of the reverse clutch...

The splines on the outer edge engage the intermediate frictions.... like so (sorry for the poor depth of field, I may come back and try and replace this pic and the next one later - using aperture priority instead of auto on the camera - making RICK proud of me)

and another view

Here it is being set onto the lugs on the top of the reverse drum

Here it is all installed.

Notice the arrow. It denotes the direction of free travel - and YES, that racheting noise is normal. There are several kinds of one way clutches... i.e. sprags.... as in the A4LD reverse and OD one ways; Roller clutches, as in the 4R70W planetary one way and earlier versions of this one way clutch, and then there is this....The Mechanical Diode. HOW it works inside I do not know. But whereas in the case of sprags the installer sets the freewheeling direction on installation by rotating it in the correct way, in this case 'worry not', it is factory preset and you cannot screw it up. The arrow is informational only.

Ok so with it installed we need to secure it. The factory retainer is shown here:

It apparently had a tendency to come off. SONNAX (god bless 'em) has an aftermarket fix. The "spiral ring retainer". It consists of a lower ring that is used to secure the spiral ring, and of course, the spiral ring itself. Here they are with the retainer on the left:

another view

can you see the raised lip on the upper one? That will get bent down to secure the spiral ring once it is installed. We start by putting that retainer on, lip side up

followed by the spiral ring. This is mildly tricky becauise the retainer has to move with you as you spiral the retainer into place... be careful there is sharp metal here. I cut my thumb really good in it. Hard to photo the spiral install but here it is best as i could.... bleeding and all..

Here are a couple pics of it all installed

all that remains is to bend over (stake) the outer lip of the underneath retainer to hold the spiral ring securely. Do this every 60 degrees or so - so you have 6 stakes....like so

All the component parts are DONE. Next up, actual transmission assembly - the "easy" part. We are rounding third base guys!

 

[Glacier991]

Next up:

Part 12 - Transmission assembly up to the Intermediate clutch

starts here:

http://www.explorerforum.com/forums/showthread.php?t=160569

 

[vegasmax]

reverse clutch...can't get but 2 & 2 installed? its a v6

The reverse clutch in this transmission sees duty when you select reverse gear. On top of it sits the "mechanical diode" that splines into the intermediate clutch. It comes in most cases as a 3 plate clutch, but can be converted into 4 plates.

I cannot see the necessity for a 4 plate clutch here.... Unless you are pulling things in reverse. Extra plates mean extra holding power but also EXTRA heat.... and unless I can justify the extra plates, well... I'm not going for it. This will be a 3 plate build.

This clutch has some things this kid has never seen before. A wave snap ring for example! Let's put one together.

We start with a new drum.... FORD Part No. F8AZ-7D044-AA Price $77.70

(pic)

Each drum of course needs a piston. FORD Part No. F2TZ-7D0402-A $28.77
Here is the piston, pretty plain Jane. Notice a check ball. If you are reusing make sure this is clean and rattles.

We need 2 seals... like most pistons, inner and outer. Here they are

We add the outer...

then the inner

and here it is all assembled.

Now these seals are kind of unique, in that they are NOT lip seals! But square cut - look

Now I know I often harp about using the seal protectors when assembling lip seal clutches. Well the old black AOD seal protectors won't work on this one. The new blue ones do... but ya know what? you can't turn a square cut seal.... so I lubed the drum.... (I use vaseline as my trans assembly lube... it's cheap and effective) first the outer periphery of the piston "pocket" in the drum

and then the "snout"...

and the piston slid right in... without protectors. Here is it seated in the bottom of the drum.

Now while there are some pistons I would never dare try and install without a protctor.... this ain't one of them. Still, use care.

Next we add an odd ring. This serves a place for the piston "spring" or "Bellville return spring" or .. to ride.... FORD part No EQAZ-7B070-A ($5.92!) Here is it being placed

and in place

Next up is the "Bellville return spring" or .. FORD part no F2TZ-7B066-B ($13.38) here it is

and here it is installed.... fingers point down and ride on the previous "ring" part.

What holds all this in place is a snap ring.... here it is from above

but wait! Look at this thing! A waved snap ring! Here are a couple of views.

In order to get it in.... we need to compress the wave plate. The AOD toolkit has a tool for this... here it is:

And here it is in place on the bellville spring

To use this tool to compress this plate, you use the clutch spring tool, but use it backwards! Installed so:

another view

and on the other side....

You tighten the nut until the spring groove is clear. The then trick is to get the wave retainer in place... a minor task but a task none the less. Once you do your best to get it in, there will be a couple places that do not compress enough to go into the grooves. I used a small pin punch and a small hammer to angle punch the spring down so it would fit, worked pretty well actually.... here is the set up

You can see the retainer is captured under the grooves. MAKE SURE THIS IS SEATED COMLETELY.

I air checked this assembly and it worked fine.

Here is the completed piston and bellville return spring and wave retainer...

So time for steels and frictions.

I had some new steels (2 to be exact) and scuffed them with carbide paper. I picked up 3 frictions from Axiom (www.aceomatic.com) for about $1.95 each... here is the FORD part No...

Thickness?

Out of curiosity I also measured the old ones from another clutch I had around...

Same. Now in fairness I do not know mow many miles the used tranny this came from had on it, or how long since rebuild, but this "kind of" illustrates my point about friction wear. Ain't much in a healthy tranny. Here is the old on top of the new...

The new has not been soaked in ATF yet so it will darken up some.

There is a front and back pressure plate. The front (first in) is the thick one.. Here is the front plate...

The side you see goes in DOWN.
Here it is in... smooth side up for the friction to ride against

on top goes a friction, soaked for 30 mins in ATF

then a steel...

in place awaiting friction #2

You add the frictions and steels, and finish with the last pressure plate flat side down onto the last friction, add a retaining ring and your clutch is together

Can you count the frictions? (Hint: there are three)

Another view

Now actually, the clearance on this pack you COULD measure with a feeler gauge.... unlike the forward clutch in this transmission. But I wanted to try out a new toy... a digital readout indicator.... so here is the measurement process using a dial (or in this case, digital) indicator....

We start by setting a zero or reference, in my case it moved a little so was .001

Then we pry up on the clutch plate/steel pack....

The result is around .046. I repeated this a few times and the results were about + or - .0015. Proper clearance ? 0.040 to 0.060... so we're good.

(btw that nifty little digital indicator was $20.)

Okay... reverse clutch is all together. The next post?

Stay tuned.... the "mechanical Diode' and the "Spiral Ring" of Death prevention.

[You just viewed two evening's worth of work... amazing how much time this takes.]

I have tried and tried...can you tell me if two is all the 2002 V6 3.8L transmissions uses? Should I put in three? I'll have to change the thicker plates to do so. It's going behind a GT40 Engine out of a explorer.
Please reply Thanks Ron AKA Vegasmax