4R70W Build Diary by Spdrcer34 | Ford Explorer Forums - Serious Explorations

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4R70W Build Diary by Spdrcer34


Explorer Addict
March 14, 2002
Reaction score
City, State
Bremerton, WA
Year, Model & Trim Level
1992 Explorer XL
I bought a 1998 Mountaineer for my wife off craigslist, that thread is here: http://www.explorerforum.com/forums/showthread.php?t=300228

The Mounty shifts fine from 1-2, and 2-1...but it doesn't shift into 3rd or OD. I tried swapping the electric shift solenoid, and it does the exact same thing. So I believe the direct drum is toast. It is probably the most common failure of this otherwise notoriously reliable transmission.

After reading this thread written by Glacier991: http://www.explorerforum.com/forums/showthread.php?t=128800 and all of it's sub threads....and when I say I read them, I more or less MEMORIZED THEM by reading them 10-15 times each. I was convinced I could re-build the transmission, and even including the new tools I needed to buy, I could do it for less than the $1850 I was quoted locally to get it done.

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..


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I will be following this thread with interest since I hope to obtain a 2000 year 4R70W in the future which will probably need some parts replaced or a complete rebuild. I assumed it would be cheaper to have it professionally done since I don't have any of the special tools or the knowledge. Is a hydraulic press required?

No hydraulic press will be required for this re-build, just a few special tools that I already have, or I have ordered.

I have just about everything, I am only waiting on the Pilot Bushing Puller, Rear Case Bushing R & R Tool, Direct Drive Solid Sealing Ring Installer Kit, and one more of the Lip Seal Protectors.

Where did you order the tools? Sometimes you could get a good deal on EBay for used tools. The cost of these specialty tools brand new is enormous. I have the first spring compressor (OTC), but not the second spring compressor (K-D). Let us know how they compare once you get up to using them. There is a third design that is supposed to be easier to use, but it's bigger, and a few times the price. It uses a foot control to press down on the clutch plates, and only takes a few seconds to insert into the tool. Do you already have a torque wrench?

I have seen the freestanding foot controlled spring compressor, but they START at $375, plus shipping which added another $40-$50 to the price. I lack the floor space to commit to 1 rarely used piece, so I will 'suffer' with the 2 small compressors I currently have.

I bought a used Rotunda Lip Seal Protector Set, both compressors and pilot bushing puller from eBay. I got the Case Bushing R&R Tool and the Solid Sealing Ring Installer from http://atec-trans-tool.com they had the lowest price I could find ANYWHERE...I searched for DAYS to find a single place to buy some stuff from....

I bought my Re-build Kit from TransParts Warehouse, and I bought my Kevlar OD band from Direct Transmission Parts, I also bought a few small parts from www.TransmissionPartsUSA.com

I am now only waiting on the Kevlar OD band, and I have everything I need.

I do not own a in/lb. Torque Wrench, which I will need for the Valve Body, but I have a couple different ft/lb Torque Wrenches with different ranges. I will borrow a friends in/lb wrench when I have to reassemble.


Thank you for posting the sources for your parts and tools. Part numbers for items you found to be particularly hard to locate would be good as well. I am interested to see how much has changed in the five years since Glacier991 did his amazing write up.

I wish you the best in this endeavor.

I will post all the part numbers of everything I have bought, once I have it all here...


I got the Transmission out yesterday on Valentines day...


I had to get it in the house SOMEHOW, and I was by myself. So I laid it on my appliance dolly (Everyone has one of those right?) and rolled it into my shop.


Then I had to get that VERY heavy transmission on the table...I didn't take the torque converter out until I got it on the table. If I had to do it again I would have removed it before lifting the transmission....


Then it was time to remove EVERYTHING from the outside of the transmission. The Heat shield. EVERY wire. Every Hose. Every Sensor. Even the transmission extension/tailshaft housing.






Now this is what it should look like....Bare on the outside. No wires, tubes, no sensors, no brackets, no nothing...if it bolts on, remove it.


Now that you have it looking like that, it's time to remove the transmission pan. Watch out though. It still has A LOT of fluid in it. I drained the case, AND the torque convertor...and it still had close to 2 quarts still in there. Then it got all over my shop!

Once you have the pan off, AND you have cleaned up the mess (if any)..it's time to start removing parts from the Valve Body. I bought a small customizable divider tray from Wal-Mart for about $4.00. It was the PERFECT size to store all the bolts, solenoids, check balls, brackets, and other small parts from the valvebody...It is absolutely necessary to keep all of those parts. And keep them seperated.


There are 2 sizes of bolts on the steel bottom plate. There are 8mm and 10mm bolts. As you take off the 10mm bolts, there are 2 that are longer than the rest. Here is the location of those longer bolts.



Once I got all the bolts removed from the bottom steel plate, its time to pull the rest of the Valve Body.





Once you have the valve body removed, there are still quite a few things still inside there. A couple pistons, the gear selector, 1 more solenoid, and the Park Pawl.



I used 2 wrenches to remove the nut on the Gear Selector Shaft. The 13/16 wrench is on the nut, while a 9/16 (tappet) wrench is up against the "Rooster Comb", holding it in place keeping it from rotating.

A picture is worth a thousand words:

Once you have that nut removed, there is only a roll pin that is lightly tapped into place, sticking out about 1/4" where the shaft enters the case. Pull it out with a pair of vice-grips, and slide the shaft past the seal and out of the case.


I didn't get a picture of the Park Pawl removal, but it is very simple. There is a sold steel rod going through the back of the case, into steel parking pawl, and into another hole in the case. There is nothing holding the steel rod in the case. No clips, screws or pins. Only the extension housing that was removed earlier holds it in place.

Here is the case I talked about earlier. The sections are segmented, and customizable. Perfect for this type of work, and they are cheap and re-usable.


Now that you have the case clear of everything on the outside of the case and everything in and around the valve body out of there....its time to mount it to the engine stand...

I used 4 - M8-1.25 x 60mm bolts, and 4 - 5/16 Brass washers. I figured the brass was softer than the steel options, and wouldn't damage the pan sealing surface. I would have preferred to find some 75mm long bolts, but the only thing I could find was 60mm, so I did the only thing I could do....I had to cut down the steel tubes that the mounting bolt passes through. I cut about 1/4" - 3/8" off of them, then ground and polished them to get them all the same length.


That takes me to the first case modification that I thought of while pulling this transmission. In the process of disconnecting the 2 lines going to the cooler, I was having a lot of difficulty with the wrench hitting part of the case casting that is no longer needed. The offending part appears to be cast in for use on the assembly line, to speed the process of lining up the drivetrain into the chassis. It's not needed, and it is in my way. So I removed it.




Pump removal:

I used 2 of the small bolts that hold the torque converter inspection cover in place, screwed them into the 2 tapped holes on the pump. I clamped onto the screws with Vice-Grips, and pulled on both at the same time, and pulled the pump off with ease.


Once I got the pump off, I just started pulling parts, and assemblies sp I could get down to the Direct Hub. As that is what the whole problem was, there was no 3rd gear. This is what greeted me when I finally saw the Direct hub...



If you can't tell, that discoloration is the tale tell sign of some SERIOUS overheating of that top plate.

Here are a few pictures of exactly how bad the clutches, and steels were in there...

Here is the bottom friction surface of the bottom clutch..it looks nearly perfect!


Here is the top of the SAME clutch..


Close-up of the same...


And finally, here is how almost all of the clutches looked.....they were all burned up, and 'cupped'. You can actually snap them in the middle, and reverse the direction of the 'cupping'. That is what caused the bright shiny outer edge of the first clutch I showed a picture of.


And here is what all the steels looked like. They were VERY damaged with heat rings, and hot spots in them.


And finally, here is the kerf cut seals that are being replaced with a solid seal in the output shaft.


Stay tuned, there is A LOT more to come.


Subscribed. I'm impressed by your ingenuity. Did you find the cause of the overheating and bad clutches? Or do you just attribute it to dirty fluid leading to clutch failure?

I honestly don't know what caused the issue. My guess is age, and lack of proper fluid change intervals. The Mounty has 150k on it. The transfercase fluid was VERY black when I drained it too.

There was no OBVIOUS signs of failure anywhere else.


Nitrile disposable gloves

Thank you so much for documenting the disassembly process. It will be very helpful to current and future members and hopefully myself! My only suggestion so far is that you purchase some nitrile disposable gloves.

Oh I bought them....They are still in the package, in the bag from the store...on the floor of my shop. I bought them when I got the bolts and washers from the hardware store.

I wasn't overly concerned with my hands getting dirty on the disassembly...it is the re-assembly that I am going to be overly cautious with the protection, and keeping everything clean!


....well, I bought my Kevlar OD band from eBay on 1/27...

I waited over a month now, I FINALLY recieved it today, and it is NOT a Kevlar band. It is the cheaper, OEM quality band that I could have bought for $14.00 locally.

It is NOT the Kevlar band.

DO NOT buy from "direct-trans" on eBay.
I paid with PayPal, and they had issues accepting via PayPal, even though the auction clearly stated to pay via PayPal. ZERO contact from them for over 2 weeks. It wasn't until I contacted them saying asking why haven't I received my Band, that he called me and said there was an issue with his PayPal account, and asked if I could pay directly to them. I paid them over the phone, and cancelled my PayPal transaction. The item was sent out on 2/14, and I didn't receive the item until 2/22. Then today when I opened the package, I saw the friction material is thin and Dark Grey/Black, and it is stamped Made in Mexico. The Kevlar Band shown in the auction has the thicker 'Green-ish Grey' friction material, and it stamped 'Kevlar' all over the place.....and it's Made in the USA.

I am SOOOO mad right now. Now I won't have the transmission back together for another week or so.


Contact them again, and see if they respond. If they don't respond, then file a complaint with EBay explaining that the item wasn't as described. You should send it back to them, and make them pay for shipping.

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I already gave them negative feedback. I don't normally give someone 3 chances, and I am sure not going to give them another. I just really need this part to get the Mounty back on the road. I should have given them negative feedback last week....Tomorrow I'm disputing the charge on my Visa card, because I never did receive the part I paid for.