Various little 4R70 Trans issues | Page 2 | Ford Explorer Forums - Serious Explorations

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Various little 4R70 Trans issues

So what your sayin is to drop the pan and VB and change all that stuff that i can out and hope it fixes it. Fluid and filter were replaced 3k miles ago, so i will reuse those. Btw when we did change the fluid, it was nasty dark, probably orginal at 141k, but no metal or anything.

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How much of the fluid was changed 3k miles ago? There is almost 13 quarts total in the system, and often just dropping the pan leaves over half. If the fluid isn't really clean looking, it'd be wise to also drain the torque convertor and a little from the cooler.

R&Ring the VB is not really hard, but it's very important to be sure of the manual valve reconnecting to the linkage properly, and not losing the small parts that are just on top of the VB(tiny screen filter and two valves/springs at the front edge). It would be smart if you take the VB off, to have a source to consult for the identification and location of those parts. It should be possible to find pictures online, but the small basic manual is available from most trans parts suppliers. Those used to be about $13 each, I think I saw them for closer to $25 last time I noticed. They have very useful pictures of almost everything inside the 4R70W.

The pan was dropped and the converter was drained, and fluid looks good. Cooler was not done, and transfer case was done at the same time. I guess i should invest in one of those books and figure out what i can and should replace.

So what all should be replaced while i'm in there? Im assuming the VB gaskets, 1-2 accum, 2-3 accum, and their springs. Is there anything else in there that should be done, and also anything in there pertaining to reverse that would cause hard engagement when cold. Be great if i could fix that too.

With 141k miles, and some shifting issues, dark fluid at one time, it's a prime time to replace all of the shift solenoids, the EPC also. Those are most prone to long term wearing out as well as sensitive to small debris(dark fluid means some friction material has worn off).

For the trouble to drop the VB, I would do as much as possible then. The labor to do one part versus all is maybe 45 minutes difference. Check out the Sonnax website, and see under 4R70W what they have for part numbers that apply to the VB. There will be an o-ring kit and two or three pressure regulator type kits. Each is helpful to any trans, new or old, but they are part of things which can correct symptoms besides a full rebuild. Each part is not expensive, two or three will be in the $50-$75 range, but in total it could be over $200 in parts for the VB and solenoids etc.

I myself basically need to do the same things to my 221k miles 98 trans. I have an odd taking off in 2nd gear issue, which might be simply one solenoid. But to take things apart and test to find the one solenoid, I'd prefer to replace them all, and the other VB/accumulator stuff. My trans I plan to rebuild for my 98 Mercury later on, so it would be great to do it now and make the rebuild easier later.

Ok so i poked around on sonnax. I came up with 1-2 accumulator kit, 2-3 accumulator kit, boost valve kit, bypass clutch control plunger valve, check balls if needed, main pressure regulator valve, O-ringed end plug kit, and along with the VB gaskets and solenoids. Am i missing anything you can think of that is vital. I don't think any of that requires special tools, and also i watched video, and he talked of a reverse servo, which was kinda like a piston that he also replaced. Didn't see that on sonnax, but with my hard engagement when cold, may be a good idea to do that too if i can.

That's good work, time well spent. The reverse servo is another accumulator like the others, yes do that also. Watching any video helps a bunch to grasp what's going on with changing the parts. You need a good small screw driver and a pick of some kind is helpful, a decent sized paperclip is also a great tool to help coax some valves out of the VB.

A nice strong snap ring pliers is also desirable, cheap versions don't always do the job. Some of the springs are very tough to get a good grip of etc.

You can source most of the parts from many places, do some hunting to see where you find fair prices and a place you think is reputable to buy from.

Well i found pretty much everything on eBay for about 160, only thing i really couldn't find was the o-ringed end plug kit. Solenoids were the most expensive 60 for the 3 piece set. Which apparently it matters about how many ring it has on it, so i'd have to pull it out, look at it and order one. Bout extra 20 for the reverse servo, so you were about right, close to 200 bucks so i'm really hoping this will solve the problems.

Sounds good, but don't forget the EPC solenoid. That's the main fluid pressure control solenoid, which affects everything.

If you search for a few of the parts online, other sources will be in the first several results. Most sources also list parts on eBay, including Summit. So you can find it all easily, these are common transmissions right now. Most of the better sources will list the solenoids properly without having to look at the old parts. 1998 was an upgrade model, many of the pre-98 parts won't work in the 98, meaning the solenoids mainly, and Sonnax has slight differences in a couple of VB parts/kits. But the key there is your trans is 1998, which lets you order parts for any 98-01 Explorer 4R70W without trouble. Some sellers may list parts overlapping from 1996 to 2001, and those are wrong listings for solenoids, or the DTRS(range sensor(where the shift cable attaches)). Those don't swap across that 97/98 model line. The difference is in the wiring, 98 began a digital DTRS, and different wiring at the solenoids, the connectors changed there, thus a different VB wiring harness.

So try to avoid sellers who suggest solenoids apply to both a 97 and 98 4R trans, or ask you for more specifics.

Check with the Sonnax website for the most accurate details of their parts. I believe that one will work if it is for other late 90's 4R's.

I posted in another thread, a fairly detailed but not complete list of items I'd replace in a 4R70W as a full service project. I went over the main items in that one post with several links. That main pressure regulator valve assembly is noteworthy because Sonnax has several parts for it, a single spring, spring and valve, plus a new updated assembly(4R70W-LB1) which replaces all of it and sounds worth the extra cost($65ish). I bought two of them with plans to hopefully install it and others, Tuesday if all goes well. I have an issue with my truck that got worse last week, when hot it tends to not drop to 1st gear, it feels like it is in 3rd or a combination of two gears. I think my shift solenoid may be the problem, but doing several of the main things should help.
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Here's that post I made from last Thursday;
I haven't looked in a couple of years. I see some sources have gone up a bit, and Amazon didn't have much before, but they do now.

I liked this for the accumulator springs, I think these are what many people use with the Jmod steps; AODE 4R70W 4R70E 4R75W 4R75E 1-2 Accumulator springs jmod | eBay

I liked this for the solenoid kit for 98-03 4R's;
That mentions Borg Warner EPC brand, many other sources don't list a brand. I saw that on eBay for $20 less and got that, same seller, shopping around is smart.

The accumulator parts are not high, but getting the group is helpful;
Those are maybe $2 less individually on transmissionpartsusa; AODE 4R70W transmission servo & accumulator pistons
But some things they want too much for.

Sonnax makes a bunch of really good VB parts for most transmissions. It's easier to browse their site and see what they have for the 4R70W, the VB stuff. Try not buy overlapping kits and parts, they do have at least three upgrade choice for the main pressure regulator, a spring, spring and valve, plus another kit I thought was more involved and better;Sonnax Hydraulic Line Pressure Booster Kits 4R70W-LB1. Here's the same kit on eBay with free shipping if you don't need $100+ from Summit; Ford AODE 4R70W 4R75E 4R75W Transmission Line Pressure Booster Kit 4R70W-LB1 | eBay

The Sonnax o-ring kit is good to do, and there may be a couple of other items, I've usually bought their bigger kits that have more little things in them(are for rebuilds that have some internal items beside for the VB).

The Transmission Line Pressure Booster Kit 4R70W-LB1 is what I suggest for the main pressure regulator circuit. I think that kit is more applicable for all applications, even though it's around $50 more than a simple valve and spring kit they also have.

UPDATE: I took the Pan and VB off, pan looked good again, so did fluid. Took Vb off and as soon as i did that plop off comes the 2-3 accum cap thing. Just came off, so im definatly assuming the problem lies within it. I took apart the VB, replaced a few things, cleaned it up, and new gaskets, soleniods etc. It was a little dirty, but gaskets still in ok shape. Im done with the part that i pulled out. Im about to go out and do the accumulators and such. Wish me luck, ill let ya’ll know how that goes....

That 2/3 cover sometimes falls off, the VB holds it up and it's small tangs don't always hold well. You can tweak those a little to make it tighter, but just so long as it holds before the VB goes back on.

Got the whole thing back together, drove it around the block, and BIG improvement in shift quality, a lot smoother shifting in every gear really. I'm surprised how much of a difference it made. I didn't drive it cold so idk if that holding gear issue is still present, but the slightly clunky down shift when slowing down is no longer there. Seems to go into drive smoother too. Hopefully tomorrow i can drive cold and see if it still hangs on to 2nd, and also go for a longer drive. Thought it was gonna be a worse job then it was. 1-2 accum was a bit of a pain, but other then that...
Credit to 4r70w Rebuild - YouTube for all the very in depth info. Couldn't have done it without it. Also thanks to everyone on the forum for the advice and help of getting parts and figuring out what to fix.

Well done. Now you can watch out for another 302 Explorer to save, or a Mountaineer of you like those.

Lol, still got work to do, a sketchy cab mount, emmsions engine light, excessive surface rust coated frame, header exhaust leak, and some power lock issues.