• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

CHUZIE's 4R70W install

77broncodriver

Full Member
Joined
Nov 21, 2009
Messages
344
This is just what happened to me, I havent traced it down to the seal yet, still in the mail.

But my 4r was just rebuilt by ford and so did the d20.

the zf is a dry case in the back so the sealed bearing for the d20 adapter is fine, but the 4r from what ford told me, hes been doing trans for 20+ years, that the 4r is a wet case so thats why the oils going strait through.

and heres where the tricky part is, the spud shaft in the d20 in the zf kit is bigger diameter than the aod because it doesnt need a seal so a stock seal doesnt work.

I took in the shaft and the aluminum inner housing to a seal shop and they found one that would work. should come in this week.

Ive taking out the d20 3 times now, each time thinking ive figured it out...

Hopefully you dont have to go through all this, Ill find out the part number on the seal if you want it.

Evan
 

Viperwolf1

Contributor
electron whisperer
Joined
Aug 23, 2007
Messages
24,344
If the spud shaft is turned down to 1.875" diameter the stock seal can be used.

Looks like National 471950 will work without turning the spud.
 
Last edited:
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
Just friggin WOW!!!

How in the HELL has this not come up before? I understand this is not a frequent conversion and we are taking a risk cheaping out on parts but goodness gracious this is nucking futs! I would have flipped my lid if I found trans fluid migrating into the D20.


Well, I am placing the project on hold until this issue is resolved. 77broncodriver, please keep us informed on your progress with this seal. I am not doing a thing until I hear back from you with the results. Viperwolf, thanks for the warm fuzzy with the P/N confirmation. I hope both of you are right.

I need another case of beer :(
 

77broncodriver

Full Member
Joined
Nov 21, 2009
Messages
344
its going to take me a couple weeks, im away at college, but I will have my dad see if the seal fits the shaft and the housing when it comes in for now. not much help
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
its going to take me a couple weeks, im away at college, but I will have my dad see if the seal fits the shaft and the housing when it comes in for now. not much help

Oh. Well that changes things significantly. So much for having a guinea pig. Hey, didn't you hear, school ain't cool :cool:

I have no problem snagging a seal and throwing it in there but I just want to have a control Bronco in this little experiment. Hell, for all I know, this seal won't be the solution or I may not even have the problem to begin with; 50/50 I guess.

Bottom line, I am going to have to take a risk and try this seal. More to come......
 

77broncodriver

Full Member
Joined
Nov 21, 2009
Messages
344
I would like to be working on the bronco but they dont let you work on cars here at all, im bored now!

But It only took about 30 min to take out the 20 and pull it apart to the seal.

Saves some time and money, that oil is expensive, have spilt all the oil twice now...
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
Of course no one has that seal at the parts houses. Looks like it is originates from a 1995 Toyota Previa DLX transfer case. I am going to try a Toyota dealer tomorrow but that vehicle has multiple seals and I guarantee I am going to catch crap at the dealership for not knowing a Toyota part number let alone the exact seal. This should be interesting.

Any Toyota gurus on here wanna hook me up with the right part #?

So far I have gathered it may be one of these...

9031223001
9031137003
9031152021
9031223001

but none of the sites give the specs so it is a shot in the dark.

We do know we need:
Outer Diameter: 2.762
Shaft Size: 2.125
Width: 0.437
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
Got mine ordered from Advanced. The Toyota dealership was zero help. All they have are part numbers, not sizes and specs on the parts. Couldn't risk getting the wrong one. Should have it by Tuesday.

In the mean time, I'm getting my butt handed to me with the exhaust rework.

Sent from my Droid using Tapatalk 2
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
So here is my reality...

Got my driveshafts back today. Two primary and two spares. Jumped under to install them and, in my excitement, failed to realize that this whole seal situation has completely placed the rest of the project on hold.

I cant install the driveshafts until after I have removed and installed the D20 to install the seal.

To remove the D20 I have to remove the twin sticks and likely lower the back end of the assembly.

To lower the back end of the assembly, I have to remove my passenger header because it is under the lip of the 4R70W pan.

To remove my passenger header I have to first convince myself there is a God and that the Bronco is worth not burning to the ground.

Damn, I wish this seal issue had come up a couple weeks ago!

Just venting. Thanks!
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,861
Sorry I just now saw your thread Chuzie. But I probably wouldn't have been much help either, as this issue just came up to me a few days ago after Evan's dad gave a call to see if we had any insight.


...To prevent having to gut the transmission to replace the output shaft as required for other 4R70Ws utilizing the Advanced Adapters 4R70W to D20 adapter, I specifically utilized the AWD 4R70W variant as its shaft length is sufficient to use the ZF to D20 adapter while only needing to cut 1/2" from the end. Eliminating the transmission dissasembly is very appealing as is the flexibility of using a ZF adapter for potential future upgrades if need be. The other advantage of using the ZF variant is the cost being less than the other adapter.

This is the first step into the dilemma though. Saved yourself some time and money (and a good call it was otherwise), but didn't notice the missing seal in the mix.

http://www.wildhorses4x4.com/product/Ford_AOD_to_Dana20_Adapter/Bronco_Transmission_Adapters
http://www.wildhorses4x4.com/product/ZF_4WD_5Speed_to_dana20_Adapter/Bronco_Transmission_Adapters

I wonder if there was a seal inside the original Mountaineer adapter housing? Do you still have it around to check? Or would the seal have been in the AWD transfer case I wonder?
Worth a peek maybe.

I didn't get the full rundown from the designer, but perhaps A/A made the shafts in the manual kits larger in that area for additional strength to resist the harsher inputs of a manual transmission. And simply because they could, not having a seal to contend with.
The AOD version on the other hand, utilizes the same seal as the stock C4 for convenience, and because they could.

When I was talking to them about this though, I was still using the AOD example, having not known, or forgotten, that Evan was using a ZF adapter kit instead.
So all info I was getting from them was flawed due to my telling them the wrong thing.
After going back and forth over the dimensions that Evan's dad gave me, vs the dimensions that everyone thought that the shaft "should" have been, we couldn't figure out why his shaft was so much larger than called for in the specs.
Figured that there would not likely have been a mis-machined shaft that made it into a kit, but didn't put 2-and-2 together that it was another shaft either.

Another clue though, should have been that Todd (Evan's dad) said they didn't get a seal with their original kit. I thought it had been left out of the kit and sent them the correct stock one, which did not fit of course.
Bummer in the summer.


This is the first I have heard of this issue.

Probably a combination of circumstances. Any others using the AOD kit won't have had the issue, and those that are using the ZF kit instead, might not have gotten to this point in their builds. You know how long some of these parts can sit around before use.
Just assumptions on my part, but they make sense.
With any luck, those that have not finished yet will see this thread and order a seal before they get to this point.


I don't understand why the spud shaft that advanced adapters supplies does not have the correct seal.

Here again, probably because the NV4500, NV3550 and ZF transmissions don't use a seal in that area, they wanted to make it as big and burly as possible to avoid breakage and reduce machining time.
And of course, the ZF kit would not normally be officially recommended by A/A for this application anyway.
For that they have their kit with a seal.

Guess we're going to have to start stocking this new seal, if it turns out to work for you guys.


I am somewhat concerned. My transmission and transfer case are empty so I am thinking about doing a 10psi pressure test using the transmission vent line and see if I get anything to come out the transfer case vent line to check for a seal issue.

Someone want to stop me before I screw something up?

You may already have ruled this out, but if not, I can't see anything that would actually be damaged by this test, but I would consider it not needed either. You know it's going to leak as the area in question is open to fluid movement.
I don't know auto trannies that well though, so someone else will chime in about damage and or need.

Basically though, many automatics are designed to be used with slip-yoke type outputs and driveshafts. At least in some of their applications.
This would necessitate having a ready supply of fluid in the seal and shaft areas. Which is why you get fluid all over everything when you pull the driveshaft out the back.
Not an issue with an EB though, which is why a seal is needed to keep the oil from moving past the output shaft chamber and transferring fluid to the t-case.


I cant install the driveshafts until after I have removed and installed the D20 to install the seal.

To remove the D20 I have to remove the twin sticks and likely lower the back end of the assembly.

To lower the back end of the assembly, I have to remove my passenger header because it is under the lip of the 4R70W pan.

To remove my passenger header I have to first convince myself there is a God and that the Bronco is worth not burning to the ground.

Damn, I wish this seal issue had come up a couple weeks ago!

Me too! Me too...


its going to take me a couple weeks, im away at college, but I will have my dad see if the seal fits the shaft and the housing when it comes in for now. not much help

Sorry you're still dealing with this too Evan. I know you wanted to drive it to school when you left. And working with your dad this week we couldn't figure out why the seal I sent you and the ones A/A had were so much smaller than the shaft!

Do you know if the new seal has arrived yet? Any news on how it fits?
Crossing fingers for sure.
Sorry I misunderstood what was going on in the beginning and was asking the guys at Advance if the stock seal would fit their AOD kit. When they said it was the same thing and should fit, it left us scratching our collective heads.
We knew it should have of course, but could not figure out why yours wouldn't. They even pulled a seal out while I was on the phone and verified that the measurements matched what was in their specs. And then called back after trying multiple seals and shafts, trial-fitting them while I was on the phone. And they all fit as expected of course.
Now I know what tiny little tidbit of info was missing from our conversations!
If your dad originally told me it was a ZF kit, rather than the AOD I was thinking it was, sorry I forgot that little gem of info when trying to figure out what was wrong.

Hopefully the news this weekend is better!
I'll give him a call tomorrow (while he's laying down in a puddle of tranny fluid no doubt) to see how it's going.

Paul
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
Paul,

Thanks for taking the time to generate such a detailed response. We are using parts in a manner in which they were not designed. These actions inherently have risks and this seal situation is certainly one of them. My impression when I started this project was it had been accomplished multiple times with the ZF adapter and was a tried and true method. I cannot get upset at Advanced or anyone on the board as I am the one who took the risk to save a couple bucks.

My transmission did not come with the adapter housing so I am out of luck there although I do not think it would fit as the OD may be different.

Here is a question, I wonder why Advanced has two adapters (AOD + ZF) where the only really difference between them is a seal and the mounting for the D20 shifter. They could easily provide the seal and have a different shifter bracket available on the ZF adapter and have one adapter for two applications. Why is the AOD adapter more expensive? Is the extra cost due to the design of the adapter? Just a thought.

In an attempt to see the glass half full, I am glad to know I have a potentially stronger shaft and, when the seal comes in next week, I am sure all will be well and we can pass this info on to others who want to do this conversion in the future. It is all about building the knowledge base. for future users.

Keep us posted on Evan's dad's progress and I shall keep you all posted on mine.

Thanks,
Mike :cool:
 

rcmbronc

Contributor
Bronco Guru
Joined
Dec 15, 2003
Messages
2,732
Loc.
Tomah WI
I have the national seal ordered and it should be here today from Carquest. Hopefully I can get the TC pulled to check it out. One thing this thread saved me alot of cussing when all the fluid was leaking out. i will let you guys know if it works.
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
I have the national seal ordered and it should be here today from Carquest. Hopefully I can get the TC pulled to check it out. One thing this thread saved me alot of cussing when all the fluid was leaking out. i will let you guys know if it works.

Fingers crossed for you man! I wonder if you can get away with installing the seal and leaving the transfer case off to look for leaks and verify this fix?

Don't forget the open side of the seal goes facing towards the transmission.

EDIT: Is this the type of situation we can even get eyes on the leak? I mean, is this a static leak that can be duplicated with cold fluid and no case pressure?
 
Last edited:

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
48,861
Don't know how busy Evan is right now, so I'll pop back in and give an update.

Yes. I would think you could verify any leaking pretty quickly. Whether you can leave the transfer case disconnected and spin up the trany, I don't know.
If the shaft is retained inside the adapter and does not mind the lack of support at the other end (transfer case), then I don't see why it couldn't be done for a limited amount of time.
Others with more auto trans knowledge might have to jump in on that though.

As far as I know there is no real pressure in that area. It's just fluid.
However, it's so much that it's potentially floating in it! When full, the trans fluid will literally flow right through even without running the engine. So you should see some action pretty quick, if it's going to happen.
But you might not have to go to that extreme either. Todd (Evan's dad) has got a clever test he's going to be doing any time now.

He's got the seal on and it's all buttoned back up. He's going to leave the transfer case empty and the drain plug out, so that once the trans is filled with fluid, it shouldn't take too long to determine if any is getting by the seal. If it does, it'll just flow right out the bottom of the transfer case.
If it seems to hold, the next step is to button it all back up and run it to see if any is forced past the seal under more "dynamic" circumstances of heat and spinning and splashing.

I imagine (but don't know for a fact) that the seal is not awash in trans fluid when driving around. It's not, or at least WAS not, common practice to design systems where any seal to the outside world was constantly bathed in oil, as this just led to weeping and dripping long before it's life expectancy was up.
So if they hold true to past methodology, then we should know for sure whether it's good for now, after they drive it a bit.

Todd did comment that the seal fit very well, but was wondering if the design of the double lip would have any bearing. The stock original has a slightly wider spacing between the two inner lips than the new one.
Might not make any difference, but it was worth noting.

Still crossing fingers!

Paul
 
OP
OP
chuzie

chuzie

Contributor
Bronco Guru
Joined
Jul 21, 2006
Messages
2,756
I feel like the people at mission control waiting for the first contact from the Mars Rovers after landing. Tension - Knife - Cut.....
 

77broncodriver

Full Member
Joined
Nov 21, 2009
Messages
344
hey all, my dad just called and said he got the tcase back in and filled up 7 quarts plus whatever was still in there and there aren't any leaks!

Hes going to get the rest of it done tomorrow and take if for a drive to make sure but I think we finally found what was wrong.

all this frustration and its just a $12 seal no one knows about, I dont see how no one else has had this problem?

Paul thanks for all the help the past couple weeks!

Evan
 
Top