How to: 4R70W Rebuild Diary Discussion, Questions, ETC

[CDW6212R]

Transmission issues are really tough to figure out for anyone but the rare trans tech, how many of those are there here?

Only general methods are wise to do unless you have access to such an expert trans tech.

Thus, begin with the fluid, be sure it's properly filled and good. Do the valve body kits when available, also adding any available Sonnax parts. Replace prone wear parts while doing the VB, such as the EPC solenoid and others, replace the seals of the accumulators, upgrading such parts as possible.

Do those basic things, being careful to assemble everything as it came apart, go slow, and see if that fixes the issues. The best case result is the problem is solved, worst case is that you end up taking it to a shop. The parts that you buy are not wasted, they are needed for any trans in any condition. So if you do end up at a shop, be sure to point out every new part that you used, so that they don't charge you again for those.

 

[JCat]

Update: Problem = slight shift flare on 3-4.

Replaced the valve body.

Shifts are now much quicker. Everything is almost 100% BUT I do get an occasional shift flare. The transmission shop said it is a problem with the torque converter, and recommended that I try this. They said it works 9 out of 10 times.

 

[Cobraguy]

Your transmission shop is so full of **** their eyes are brown! The 3-4 flare has absolutely NOTHING to do with the converter. It has EVERYTHING to do with the timing of the clutch/band release and apply. What a crock of crap. Plus, that friction modifier you are showing is what we put in positrac differentials. I have never heard of putting it in an automatic transmission...and even if it works, who is to say what long term effect it will have on the clutch material.

Since the timing of the 3-4 shift is electronically controlled, you may have to get the mechanics as best you can, and leave the rest up to the ECM.

Oh yea...go find a different trans shop. Converter. What a joke of an answer. Ask them how the converter can flare a shift!!?!!??

 

[JCat]

Since the timing of the 3-4 shift is electronically controlled, you may have to get the mechanics as best you can, and leave the rest up to the ECM.

.
I just want to know how to fix this problem ?

 

[Cobraguy]

So does half the world. I have tried different servos, pin lengths, valve bodies, etc etc. I can improve it, but I've only had one that was what I would consider excellent in all conditions. All seem to have some situation or another where they flare. So I'm not the one who can give you a definitive cure. But I've been building trannies for 40 years now...and I can definitively say the converter isn't going into neutral and causing a flare!! LOL

 

[CDW6212R]

I agree on that, the shop is likely guessing that the user is wrong about it being the 3/4 shift, and they think it's just the converter locking while in one of those gears. They are making assumptions, wrong most of the time.

I'd suggest raising the line pressure, either with a PCM flasher to alter the programming, or install the later 4R75W EPC solenoid, which makes more pressure by itself.

The issue is likely a fluid pressure loss from one or more places internally, usually the VB. Every seal in the trans helps to hold pressure, so it could be from several tiny things. Do the easy stuff, replace the EPC, and add the Sonnax VB parts, including the o-ring seal kit.

BTW, one of the Sonnax VB pressure valves is for making greater pressure than their normal high pressure regulator valves. I don't recall which one, but read the choices, and if you swap to the later high pressure EPC, don't also use the highest pressure Sonnax VB valve.

The PCM programmers can alter the line pressure and shift timing a good bit I gather, that could be the easiest or the final solution if all else fails. That takes some time though, contact James Henson about it.

 

[Cobraguy]

Keep in mind that the 3-4 shift on this trans is the only "timed" shift there is. The rest is just the simple application of a band or clutch to change gears. But the 3-4 requires both a release and an application to make that gear change. They have to be timed perfectly. I'm pretty happy with mine. Under light throttle conditions, I can get a slight flare. But with any load at all, the shift is clean and quick. Or, if I manually shift it at any throttle angle by pushing the OD button the shift is clean and quick. (never quite understood what is going on there that changes the shift like that) I know it's possible to get it to shift properly in all conditions because I had one. But just one. It's a tough dilemma for sure.

By the way, that Friction Modifier is the best stuff I've found...for a posi rear end. It would NEVER, EVER go in a trans of mine.

 

[CDW6212R]

I have heard of it for a trans, but I forget where that was, and I don't think it's a good idea.

There is already an excellent additive for any auto trans, by Lubegard. They have been making those for 20+ years at least, and are highly recommended by most experts. If you need to try something, try that.

 

[JCat]

I just put the Mountaineer through a torture test. We spent the whole day off-roading in the Chattahoochee National forest. Except for a lot of suspension squeaking, everything (including the transmission) functioned perfectly.

The flare happens very rarely...it is still there . . . I guess I'll just learn to live with it.
.
.

 

[CDW6212R]

Hello Alan, welcome, I have not spoken with you since buying just the OEM intermediate and direct clutches. I still have not finished that trans.

I had asked you about details of what to do with the truck VB, what holes to drill etc, similar to the "J" mod. I later bought what is supposed to be a 2003ish Mustang VB. I need to be sure it is a car VB, and then build it with the "J" mod etc. Is the car VB something that you can tell from a truck easily?

 

[DirtyD0g]

Hello Alan, welcome, I have not spoken with you since buying just the OEM intermediate and direct clutches. I still have not finished that trans.

I had asked you about details of what to do with the truck VB, what holes to drill etc, similar to the "J" mod. I later bought what is supposed to be a 2003ish Mustang VB. I need to be sure it is a car VB, and then build it with the "J" mod etc. Is the car VB something that you can tell from a truck easily?

yes they are very easy to tell by the seperator plate, the truck have many changes but the easy one is one of the holes you drill out to make a car vb shift firmer, on the truck it is a slot.
Alan

 

[CDW6212R]

Thanks Alan, I'll get the VB out and get a look at the VB. I think it was a take out part, everything was covered in ATF like it just came out of a trans.

 

[berniemac73]

Guess what happens when you get your bearings in the wrong spot? You get to disassemble and start over. Very important to know which is goes where. Case/tailshaft bearing also fits reverse drum and seems normal until it stops pump about 1/16th from seating. There is another bearing (dunno what it's called) that "fits" in another place until you get to pump assembly install. I didn't have luxury of new bearings in the bag and labeled. Thank you for your diaries I'd be lost without it. Internet acts like Aod 4r70w is top secret info.

 

[92eddie4x4]

Hello, where do I go about to buy all of these tools, in quote below? Is there a board member who already has them all who is willing to loan them out?

Spdrcer34, I noticed that you are in Bremerton. I am planning on doing my 4R70W rebuild at my father's in Gig Harbor, would you be willing to rent me your tools? This would be my first transmission rebuild and any help is appreciated. Thanks!

I have purcchased, or already had the following tools:

Lip Seal protector set (seen in various posts/pictures, here are a couple)

Pilot Bushing Puller

Clutch Spring Compressor

I also just bought THIS spring compressor:

Rear Case Bushing R & R Tool

Direct Drive Solid Sealing Ring Installer Kit

I have also purchased a new Digital 6" Caliper, and the 4r70W manual from ATSG...


Now I still need to source the following parts:

Small tipped snap ring pliers:

I still need to buy that bowl shaped spring compressor, once I have everything here, I will make a build diary like Glacier991 did..

Ryan

 

[Cobraguy]

Go on to eBay and do a search for "Rotunda". All kinds of factory tools at a discounted price will show up. Some sellers are trying to rape you...others are being very fair...so keep looking. Some of these tools are not factory though and can be bought in many different places for reasonable cost. I bought all mine because I build a few transmissions now and again. Trying to find a place to rent them though may be tough.

 

[Mountinheer]

Hopefully, this thread isn't too old to get a reply - it's certainly got some knowledgeable followers!

I have a super simple question that I have been digging to find an answer to for days (ok weeks... but really digging for days)... I'm learning alot, but still have not answered my simple question. To make this more fun, I'll give you some back-story before revealing the question (skip to the end for a spoiler)...

I've got a 2001 5.0 AWD Mountaineer I've owned for about a year (long enough to fall in love with it's sheer functionality). The drivetrain has been complaining since day one, and I finally decided to dig in and fix it. Now I would have sworn to you that the complaint was coming from the front end... but I would have been wrong. Either way, this suspicion led me to the concept of converting to the BW4406 manual shift T-case with low-range. Knowing that the rear was really the problem, I probably would not have bothered with the T-Case change, but I'm glad I did. I think.

So I did the swap in my driveway with the help of a few jack stands and another excellent thread on this forum. I found the installation of the case to be nearly impossible (even with 3" body lift), and almost gave up. By some miracle, I did not lose any fingers in the many failed attempts to lift the beast onto the unassuming shaft coming from the 4R70W. With every protruding ear ground off, and the front output 'beak' neatly wedged in my armpit, my last ounce of will-power found the monster sliding onto from the aforementioned shaft. Another miracle keeps the behemoth up there as my puny arms flop to the ground in complete exhaustion.

I tore a slot into the bottom of the old gasket that went between the cases and slipped it around the shaft. I figure if something leaks in there I'd rather know it...

I should back up a bit. When I separated the cases, I got shot of red to the chest which I assumed came from the old T-case. Hindsight...

After a drive to work and back, the undercarriage has a nice ATF coating. I freak out and think the (not so) remaned T-Case I bought has gone dry. A quick slide underneath (thx to whomever installed 3" lift and 31's) and the T-case won't take more than 2 oz.... I install a new yoke seal just in case. Another drive to work, more rust prevention... now no oz's. uh oh. That unassuming seal on the unassuming shaft that was already leaking did not appreciate the extreme trauma it recently endured....

Maybe the leak isn't that bad? Maybe there's a miracle cure that won't completely destroy the trans? The fluid level still looks OK... so I add way less than the recommended dosage of something that feels like brake fluid on my fingers. No dice. I try to take off from a light and get way too much RPM before she grabs. O crap. I got what I deserved for taking the easy way out...

Back home and check the fluid again... NOW she's low. 2.5 qts of the good stuff and we're back on top - My brief celebration is interrupted by my realization. I know what I must do... But I REALLY don't want to.

Week by week, and quart by quart... I start making a plan. My friend has a lift, I'll grab a trans output seal a go do this the way I should have the first time. It'll be easy because the dam thing fits already. Ok, Google. Please provide me with one transmission output shaft seal for a 2001 Mountaineer AWD 5.0. No, that's the one on the T-case output. Cast iron? Teflon? No, Google.... TRANSMISSION. OUTPUT SHAFT SEAL. Listen when I speak please. What is all this crap? Just give me a diagram and I'll find it.....

....
....
....

Ok... ya, I'm not sure either. Sorry for yelling. Thanks for leading my back to ExplorerForum. I know, I know... I should have just started here...

So, ahem:

Could someone help me with the part number for the seal on the output shaft between the trans and transfer case? Not the iron/teflon seal that means complete disassembly (please god)... The rubber seal that is easily replaced after removing the T-case?

 

[Turdle]

Hopefully, this thread isn't too old to get a reply - it's certainly got some knowledgeable followers!

I have a super simple question that I have been digging to find an answer to for days (ok weeks... but really digging for days)... I'm learning alot, but still have not answered my simple question. To make this more fun, I'll give you some back-story before revealing the question (skip to the end for a spoiler)...

I've got a 2001 5.0 AWD Mountaineer I've owned for about a year (long enough to fall in love with it's sheer functionality). The drivetrain has been complaining since day one, and I finally decided to dig in and fix it. Now I would have sworn to you that the complaint was coming from the front end... but I would have been wrong. Either way, this suspicion led me to the concept of converting to the BW4406 manual shift T-case with low-range. Knowing that the rear was really the problem, I probably would not have bothered with the T-Case change, but I'm glad I did. I think.

So I did the swap in my driveway with the help of a few jack stands and another excellent thread on this forum. I found the installation of the case to be nearly impossible (even with 3" body lift), and almost gave up. By some miracle, I did not lose any fingers in the many failed attempts to lift the beast onto the unassuming shaft coming from the 4R70W. With every protruding ear ground off, and the front output 'beak' neatly wedged in my armpit, my last ounce of will-power found the monster sliding onto from the aforementioned shaft. Another miracle keeps the behemoth up there as my puny arms flop to the ground in complete exhaustion.

I tore a slot into the bottom of the old gasket that went between the cases and slipped it around the shaft. I figure if something leaks in there I'd rather know it...

I should back up a bit. When I separated the cases, I got shot of red to the chest which I assumed came from the old T-case. Hindsight...

After a drive to work and back, the undercarriage has a nice ATF coating. I freak out and think the (not so) remaned T-Case I bought has gone dry. A quick slide underneath (thx to whomever installed 3" lift and 31's) and the T-case won't take more than 2 oz.... I install a new yoke seal just in case. Another drive to work, more rust prevention... now no oz's. uh oh. That unassuming seal on the unassuming shaft that was already leaking did not appreciate the extreme trauma it recently endured....

Maybe the leak isn't that bad? Maybe there's a miracle cure that won't completely destroy the trans? The fluid level still looks OK... so I add way less than the recommended dosage of something that feels like brake fluid on my fingers. No dice. I try to take off from a light and get way too much RPM before she grabs. O crap. I got what I deserved for taking the easy way out...

Back home and check the fluid again... NOW she's low. 2.5 qts of the good stuff and we're back on top - My brief celebration is interrupted by my realization. I know what I must do... But I REALLY don't want to.

Week by week, and quart by quart... I start making a plan. My friend has a lift, I'll grab a trans output seal a go do this the way I should have the first time. It'll be easy because the dam thing fits already. Ok, Google. Please provide me with one transmission output shaft seal for a 2001 Mountaineer AWD 5.0. No, that's the one on the T-case output. Cast iron? Teflon? No, Google.... TRANSMISSION. OUTPUT SHAFT SEAL. Listen when I speak please. What is all this crap? Just give me a diagram and I'll find it.....

....
....
....

Ok... ya, I'm not sure either. Sorry for yelling. Thanks for leading my back to ExplorerForum. I know, I know... I should have just started here...

So, ahem:

Could someone help me with the part number for the seal on the output shaft between the trans and transfer case? Not the iron/teflon seal that means complete disassembly (please god)... The rubber seal that is easily replaced after removing the T-case?

Do you mean this?

2001 FORD EXPLORER 5.0L V8 Seal | RockAuto

 

[Mountinheer]

Do you mean this?

2001 FORD EXPLORER 5.0L V8 Seal | RockAuto

Are you suggesting the seal on the output of the T-case and transmission are 1 and the same? If this is the case, I will cheer - but I couldn't find it called out that way in a drawing...

Or is this the trans seal I need, and I'm talking about the 'extension housing' seal??

 

[Turdle]

That seal was listed in the transmission section under "seal" . The parts diagram would not show a transfer case seal as that t-case was not offered in an explorer.

From the looks of it that is an output shaft seal.

 

[Cobraguy]

Jon...that is for a 2 wheel drive trans.

Boy...it's been a while since I've been in one of those, but I'm betting you are pulling the transfer case and replacing that gasket you cut. I actually have that exact trans in storage. I'll see if I can't run over and take a look at it and see what's there.

If you pull the transfer case, rent a trans jack!!! Shoot...go buy one at Harbor Freight for $50 if nothing else. Those things can kill you if you drop it on you.