J-Mod on 4R70W

[jakemccarthy]

I have read quite a lot about the J-mod on this and other forums. I have heard that you should not do it on a truck, and that you should. I have also heard that I need to find a valve body out of a car and swap it. But at the same time some people say that I dont have to if I have a certain year, and others say that its all nonsense, and that you can do it on a truck. So whats the deal?

 

[jakemccarthy]

Anyone

 

[XLT]

Here is a little reading material to point you in the right direction.

 

[Theroseman]

Jmod

Sry this is a little late, but I recently did the j-mod on my 96 explorer 4r70w and it works perfect. I did a lot of research and decided to go for it. My truck shifts like a dream. I highly reccomend doing it to your truck. If anyone has any questions about hole sizes or charts, I would be happy to share.

 

[fastfocus2005]

J-Mod

I also did the J-mod to my '96 5.0 AWD and has nice snappy firm shifts. Haven't had any issues. I also recommend it to anyone with a 4r70W. There is a tech article on tccoa.com website that tells you step by step how to do it and gives you all the Ford part numbers that you can pick up at the dealer for about $80. I used this tech article and it is very helpful.

 

[JCase]

Have you figured your valvebody out in the last 6 months Jake or is this thread a victim of a day late and a dollar short?

 

[fastfocus2005]

J-mod

....You do not have to swap out valvebodies, only modify a few holes in the separater plate and change the accumulator springs and remove return springs....

 

[traveler]

Does anyone know if Ford did any changes to the 4R70W from 96 to 2000 I should know about? (little things like springs valves etc) Contemplating doing the upgrade to my explorer soon. I did my Tbird years ago and loved it.

 

[CDW6212R]

Truck VB's often don't react the same way to VB kits, sometimes they work the same, but often they don't. Many are fortunate. The same goes for the old AOD police VB's, and I found that out the hard way. Those AOD's have a manual 2nd gear selection, no 1st on the pattern, and the B&M kit I put in gave me harsh low throttle shifts from 1st to 2nd and sometimes 2nd to 3rd.

The safe bet is to use any comparable model car VB, say a 98+ Mustang VB for any 98-01 Explorer. Those work great with any VB kit, and the J-Mod too.

The J-Mod is a relatively simple modification, so it isn't the hardest to do for anyone.

The early 4R70W's have different cases and a few lesser things that are upgraded from 98 on. The 98+ have different solenoids, and different matching wiring connectors, the harness etc. You can swap them, but it's not smart to mix them up that way(hell to remember later on what got changed).

 

[VR4]

I did mine on the 1-2 and it shifts great. Left the springs in since it's awd. I'll have to pull up the diagram I used to remember exactly what I did.

In my other one I'm gonna find a car VB and do more since it's only rwd.

 

[traveler]

Mine is actually 4WD. I've done the BW4406 swap.
I don't mind doing a J-Mod, but don't like the idea of swapping out plugs and solenoid. I like just removing the valve body and returning the same modified body.

 

[VR4]

http://www.crownvic.net/tech/4R70Wnotes.pdf


Iirc I drilled hole 2 only. 4, 5, 9, and 11 were already larger than the sheet said.

Gave me exactly what I was looking for. Firm and quick 1-2 shift only.

 

[CDW6212R]

Changing the EPC solenoid and if high mileage, the other solenoids, plus Sonnax VB parts, those are great improvements for any trans. I'm just doing that today on my new 98 truck. I'm hoping it will do okay for a few months until I build a 4R from scratch.

I saw two 2004 Mustangs today at the P.A.P. yard, one with 236k miles and the other with near 150k(oil stickers on windshield). I'd like to get the better of those two to build one with. The 2004 V6 trans has the J'Mod upgrades already, plus all other hard part improvements. The mileage is the worrisome part, you want the trans case to be unworn at the solenoids etc. All I bought were a couple of fender flares, the thin ones.

 

[sicaz66]

Getting ready to jmod my '97 . What holes and what sizes?? Mine doesn't have a #5 hole? Seems I get different info from every site?

 

[CDW6212R]

Update, the Jmod is desirable for any 4R70W, but there are differences in the VB's and plates(hole sizes) of many models. So the "sheet" or instructions you find online will ne applicable to some but not all 4R vehicles. The 2001+ models are the most predictable(results) given the instructions(hole sizes to drill). Trucks before 2001 will have the most unpredictable plate hole sizes, and the accumulator springs used, plus some VB parts used.

So you need to research well the application you have, figure out what the holes suggested are for etc. You need to know what each hole size is used for, and decide if what is being suggested is more(hole size) or less than you need.

I'm hoping to do mine today, I've been collecting parts to do what I can to update the stock 99 Limited I just got. The Jmod is a last thought, I began researching what holes would be best for me, and the accumulator springs too for the 1/2 and 3/4 shifts.

Be aware that the accumulator springs have a significant effect on the shift timing and firmness. It's not as simple as drilling some holes and leaving the stock springs in place, or removing them. You need to know what the suggested holes and springs were intended for. I'm gathered that the 1/2 accumulator springs almost always should be the suggested OEM part numbers F75Z-7F284-AA and F75Z-7F284-BA. The TCCOA forum has lots about the Thunderbird/Cougar and Mark VII cars, using a couple of other spring colors(also OEM). I think all of those were experimented for each person, and not ideally used by models other than those cars.

So I'm going to use the two most suggested springs above, and likely a 2/3 OEM spring suggested by someone doing truck VB's, on an F150 forum. The hole sizes you choose for the main 1/2 shift(hole #2) and the 2/3 shift(holes #4 and #5) will have the most controllable effect on shift qualities, given the springs suggested. Meaning you can easily alter the hole sizes, by removing the VB to get to the plate. I think I'm going to try the .078" drill size for hole #2, that's a figure suggested for truck VB's by a member of an F150 forum. Going bigger(which is in the Jmod instructions) can get you very harsh 1/2 shifts. Remember it's easy to make the holes bigger, tough to make them smaller.

 

[fastpakr]

Don - any update on your results with this? I'm about to start my engine swap and want to make the changes before installing everything. I'm not absolutely certain on the trans year as it's not in my hands yet, but I believe it's in the '99-01 range. Will update as soon as I can confirm. Thanks!

 

[CDW6212R]

Don - any update on your results with this? I'm about to start my engine swap and want to make the changes before installing everything. I'm not absolutely certain on the trans year as it's not in my hands yet, but I believe it's in the '99-01 range. Will update as soon as I can confirm. Thanks!

I'm sorry to say I've not found the time to do it yet. I'm still delivering mail full time with it, and trying to finish my V6 trans, SOHC timing chains etc.

I can suggest this for sure though. Take lots of notes of what you find online from others and their applications. The hardest part was reading through the tons of other individual J-Mod holes sizes, and which springs they used. It's different for every application, so us Explorer guys ought to post our actual holes sizes, and springs. I still have the parts I mentioned above, the hole sizes are the tuning items(you can obtain harder or softer shifts by the hole sizes, and alter them if needed again).

 

[Spudhut]

This is interesting (The J-Mod). Is this for firmer shift points between 1/2 & 3/4? I will eventually drop my pan and put in all new fluid/filter in my trans. I figure, I might as well do any simple modifications to help improve it any way I can. My 97' V8 is an AWD but will be getting a Manual TC swap soon for true 4 wheel drive selections from the floor, SAS and SOA.
Would this benefit me in any way?

@CDW6212R - you mention researching the trans. Are we determining the type or model of trans we have or researching which VB that is installed?

Does anyone who has done this have any updates? Photos on how to?

 

[CDW6212R]

There are tons of examples of people doing it for their Thunderbirds, Mark VIII's, Mustangs etc, all with the 4R70W trans. It's good for any vehicle, but it's a shift improvement that can be made to be very harsh, or mild etc. Different sized holes and different accumulator springs will result in different results for various vehicles. People have random likes and dislikes for shift quality, so it's very hard to read what others did, and know what you need or want. The Explorer has few examples to go by, nobody posts the details of what they did with their trans.

So it's a good idea to be ready with a plan when you drop the pan, if not just do the fluid and filter until you can be ready later. I've got a group of things to do, I just haven't had time to spend the half day it'll take to do it.

 

[fastpakr]

Just wanted to check - had a chance to try the JMOD yet @CDW6212R?