J-Mod For 4R75W Trans??

[Marauderjack]

Barry sent me the information on the J-Mod but it is for the 4R70W trans.....and Jerry stated that "some of his mod is incorporated in the 4R75W trans".....I wonder what has already been done to it??:help:

Also, Zack says to use a "prop/spacer" in the accumulator bore to stabilize the piston?? Details please??:confused:

Any other tips will be greatly appreciated!!:beer:

MERRY CHRISTMAS!!!

Marauderjack:burnout:

[Zack]

There is no difference between the two transmissions in regards to the J-Mod.

About the spacer, its exactly how it sounds. Find a bar or bolt and cut it to fit betwen the accumulator piston and the retaining cap. If it is too long the valve body wont bolt down and seal. I dont have pics, sorry.

[hidperf]

I've been reading up on this J-mod and everything I see is for older transmissions. Is the article on the t-bird page applicable to the 03 4R70W's in our cars?

[safado]

Merry Xmas guys... I should be doing this in some days... Have my buddy locating a spare separator plate.... the idea to "lock down" the pistons sem like a new addition to the original J-mod... I assume its new and improved?

[CRUZTAKER]

I've been reading up on this J-mod and everything I see is for older transmissions. Is the article on the t-bird page applicable to the 03 4R70W's in our cars?


The document was written for OUR trannies in mind!

PM email addy for a copy.;)

[JACook]

Merry Xmas guys... I should be doing this in some days... Have my buddy locating a spare separator plate.... the idea to "lock down" the pistons sem like a new addition to the original J-mod... I assume its new and improved?

Locking out the accumulator piston is, I believe, a "Z-Mod".
I'm not entirely certain that "J" would approve...

[Marauderjack]

Locking out the accumulator piston is, I believe, a "Z-Mod".
I'm not entirely certain that "J" would approve...

So......should I just remove the spring and forget the spacer Jeff??:confused:

I plan to do the J-Mod sometime this week!!:beer:

Marauderjack:burnout:

[Zack]

Killjoy recenntly had a trans failure due to the lip on the accumulator piston folding over and causing the direct clutch to burn up. It would have been prevented had the "z-mod" been in place. FYI, I did not invent it, its been around for years.
A rod cut to length for this purpose is included in the Trans-Go shift kits.

[Marauderjack]

Would a piece of PVC pipe work OK??:confused:

Easy to cut to length and melting point is way above trans fluid temps!!:beer:

BTW, does this "spacer" keep the piston at the bottom of the bore??:confused:

Marauderjack:burnout:

[Zack]

Would a piece of PVC pipe work OK??:confused:

Easy to cut to length and melting point is way above trans fluid temps!!:beer:

BTW, does this "spacer" keep the piston at the bottom of the bore??:confused:

Marauderjack:burnout:


No its not ok:help:

[Zack]

Here is the 2-3.

http://www.dndgarage.net/j%20mod02.jpg


Above this plate is the spring. Above that is the accumulator piston. The spring is removed and leaves the piston floating in the bore. The goal is to keep it bottomed out (really as far up as possible)
This should give you an idea of how easy it is to make a bolt or rod of sorts to length to achieve the goal.

Follow this guide and you will be golden:

http://www.dndgarage.net/jmod.htm

[Marauderjack]

Thanks for the link Zack......Photos really help!!!:beer:

Marauderjack:burnout:

[Marauderjack]

OK Zack.....I read the article and nowhere does it mention a spacer or putting anything in the piston bores??:confused:

If these "accumulators" are simple shock absorbing devices to smooth out shifts wouldn't the pistons stay at the bottom of the bores after the springs are removed anyway??:cool:

It seems to me if the pistons are propped at the top of the bores they would only displace the fluid used to fill the accumulator bores....if I'm understanding this right??:confused:

Marauderjack:bandit:

[Local Boy]

I had my trans guy put in a 1 inch dia. copper pipe cut to length, in both bores (1-2 , 2/3 ). I've been told it will shift harder with a soild piece in place...

BTW: Don't use plastic...

No problems so far... Shifts great!!!

ALOHA

[JACook]

Killjoy recenntly had a trans failure due to the lip on the accumulator piston folding over and causing the direct clutch to burn up. It would have been prevented had the "z-mod" been in place. FYI, I did not invent it, its been around for years.
A rod cut to length for this purpose is included in the Trans-Go shift kits.

Well, Jerry's opinions regarding Trans-Go are well documented, so let's just say I'm unconvinced.

To quote:

"A lot of shift kits put a blocker ring in the 2-3 accumulators. This limits the amount of travel
for the accumulator. And yes, it does result in firmer shifts. But don't do this. What is happening
is this; if you remember the accumulator explanation from before, it allows a slower pressure rise
in the clutch while it is applying. This accumulator stroke limiter forces the clutch to go to line
pressure faster, but the way it does that is by stopping the accumulator from stroking thus ending
the ramp. When you allow a shift to finish, meaning the clutch stops, when the accumulator stops
stroking, it puts a large shock load into the transmission and driveline, which will result in eventual
failure of something"

So, perhaps your 'fix' might have prevented one potential failure mode, but you have to ask what
other failure modes may result from blocking the accumulator.

Long before I ever knew there was a Jerry W., I learned the hard way about what kinds of problems
result from blocking accumulators, amongst other 'Trans-Go' (and B&M) shift kit mods. I amassed
a pretty nice collection of broken hard parts, and this was with a street car, on street tires. Once
I learned to back the transmission off 'kill', I stopped killing transmissions. Go figure.

So, no offense, Zack, but BTDT. Killjoy's accumulator failure strikes me as just a fluke, not as a
reason to disable it. I woulda made sure the accumulator bore was nice and smooth, and then
just replaced the accumulator, and left it functional. It's one thing to shorten the clutch apply
ramps to firm up the shifts, but quite another to make them binary. Slamming clutches on is a
good way to break parts.

Y'all might wanna go back and read Jerry's tutorials on clutch apply rates and accumulators
and such...

[Marauderjack]

Well, Jerry's opinions regarding Trans-Go are well documented, so let's just say I'm unconvinced.

To quote:

"A lot of shift kits put a blocker ring in the 2-3 accumulators. This limits the amount of travel
for the accumulator. And yes, it does result in firmer shifts. But don't do this. What is happening
is this; if you remember the accumulator explanation from before, it allows a slower pressure rise
in the clutch while it is applying. This accumulator stroke limiter forces the clutch to go to line
pressure faster, but the way it does that is by stopping the accumulator from stroking thus ending
the ramp. When you allow a shift to finish, meaning the clutch stops, when the accumulator stops
stroking, it puts a large shock load into the transmission and driveline, which will result in eventual
failure of something"

So, perhaps your 'fix' might have prevented one potential failure mode, but you have to ask what
other failure modes may result from blocking the accumulator.

Long before I ever knew there was a Jerry W., I learned the hard way about what kinds of problems
result from blocking accumulators, amongst other 'Trans-Go' (and B&M) shift kit mods. I amassed
a pretty nice collection of broken hard parts, and this was with a street car, on street tires. Once
I learned to back the transmission off 'kill', I stopped killing transmissions. Go figure.

So, no offense, Zack, but BTDT. Killjoy's accumulator failure strikes me as just a fluke, not as a
reason to disable it. I woulda made sure the accumulator bore was nice and smooth, and then
just replaced the accumulator, and left it functional. It's one thing to shorten the clutch apply
ramps to firm up the shifts, but quite another to make them binary. Slamming clutches on is a
good way to break parts.

Y'all might wanna go back and read Jerry's tutorials on clutch apply rates and accumulators
and such...

Thanks Jeff,

Where might I find Jerry's "Tutorials" on these subjects??:confused:

Marauderjack:burnout:

[Marauderjack]

OK Folks.....New dilemma!!!:mad2:

I went to my FLM dealer to get the two gaskets and the guy came out with a "1W7P-7D100-AB" which is WRONG...should be a "Z" and a "1L3P-7C155-AB" when it calls for a "P" and an "AA"????:argue: He goes back and brings out the plastic bag they came in and it reads right but printed on the gaskets are the other letters???:confused:

Is this correct?? Maybe Ford changed the part number as they do all the time??:shake:

I only want to do this once so I need to be sure I have the correct gasket(s)??!!:cool:

Marauderjack:help:

[Zack]

So, no offense, Zack, but BTDT. Killjoy's accumulator failure strikes me as just a fluke, not as a
reason to disable it. I woulda made sure the accumulator bore was nice and smooth, and then
just replaced the accumulator, and left it functional. It's one thing to shorten the clutch apply
ramps to firm up the shifts, but quite another to make them binary. Slamming clutches on is a
good way to break parts.

Y'all might wanna go back and read Jerry's tutorials on clutch apply rates and accumulators
and such...


Its obvious how you feel about this topic! :D

Ask BC Automotive and Art Carr if they install this rod in the accumulator bore.
Their answer will be yes ;)

Yes, this 2-3 discussion is new to this board, but not new to 4R70w transmissions.

[Marauderjack]

OK Folks.....New dilemma!!!:mad2:

I went to my FLM dealer to get the two gaskets and the guy came out with a "1W7P-7D100-AB" which is WRONG...should be a "Z" and a "1L3P-7C155-AB" when it calls for a "P" and an "AA"????:argue: He goes back and brings out the plastic bag they came in and it reads right but printed on the gaskets are the other letters???:confused:

Is this correct?? Maybe Ford changed the part number as they do all the time??:shake:

I only want to do this once so I need to be sure I have the correct gasket(s)??!!:cool:

Marauderjack:help:

I think I found the answer......my parts guy says the number printed on the gasket is and "engineering number" and they go by the package number and that is what it is supposed to be.....so I guess I have the correct parts??!!:beer:

As far as the spacers......I'm not interested in getting the final tenth of a second out of the car on the 1320.....it's just that the shift firmness with my tune still allows a slight delay in the 1-2 shift....then it hits hard and I think the removal of the spring and enlarging the holes in the separator plate will do the trick!!:bows:

Thanks for everyone's input!!:D

Marauderjack:burnout:

[Zack]

When you go to the parts counter, simply ask for 7D100 and 7C155

[Zack]

I may as well say it now....

If you have 155k on a stock unmodified trans and gobs of SC miles on it, I think doing this J-Mod will show you the weak links of the trans and you will soon be removing it for a complete rebuild.

[Marauderjack]

I may as well say it now....

If you have 155k on a stock unmodified trans and gobs of SC miles on it, I think doing this J-Mod will show you the weak links of the trans and you will soon be removing it for a complete rebuild.

That, my good man, is the exact course of action!!:beer:

BTW, what do you think will break first??:eek:

Thanks for confirming the part numbers too!!:D

Marauderjack:burnout:

[sabtaj1]

I did the full J-mod. I have a 3500 stall and it really made a big difference. I am very happy with the way it turned out. I still dont think its near as harsh as it sounds though. The way I was told it was too harsh of shifts. That is not the case at all.

[Darrin]

Killjoy recenntly had a trans failure due to the lip on the accumulator piston folding over and causing the direct clutch to burn up. It would have been prevented had the "z-mod" been in place. FYI, I did not invent it, its been around for years.
A rod cut to length for this purpose is included in the Trans-Go shift kits.
Sorry buddy, I really hate to contradict you on this, but don't do that.

What they did to the transgo stuff is very different and needs other mods to make it work properly. Blocking off that accumulator without the other stuff done is a very bad idea. Heck, it was a very bad idea even with the other stuff done.

Also, if the proper accumulator cap is used there is no way that the piston can travel far enough to come out of the bore. Every single instance of lip damage to the piston that I have ever seen was caused during assembly.

Darrin

[Darrin]

I did the full J-mod. I have a 3500 stall and it really made a big difference. I am very happy with the way it turned out. I still dont think its near as harsh as it sounds though. The way I was told it was too harsh of shifts. That is not the case at all.
With that stall the shifts won't be harsh, they will just be very quick. If you did that same mod to a car that had a stock stall converter in it the shifts would be a whole lot harsher as well as very quick.

The converter is absorbing the hit on your setup.

Darrin

[Zack]

Thanks for the reply Darrin.
Just answer me this, when 'the other stuff' is done inside the trans, do you install the rod in the accumulator?

[Darrin]

The other stuff is what TransGo does to the valve body and that stupid plug they put in the back of the transmission. I don't do any of that stuff. LOL

Blocking off that accumulator on a street driven car is just a bad idea in my opinion.

Darrin

[Marauderjack]

Hmmmmmm...........this thread has become very interesting and educational!!!:beer:

That's why I always ask questions before ruining stuff.....heck I can even break stuff knowing the right things to do!! :mad2: :shake:

Thanks for your input Darrin.....I'll just do the basic J-Mod as outlined in the literature I got from Barry!!:D

Marauderjack:bandit:

[Local Boy]

Ohoo, Looks like I may be taking out the copper pipe then...

I understand the increased shock load, to the hard parts... when the accumulator is blocked off...

Question: Having a 3,500 stall TC, on a mildly (bolt ons) modded motor...Doesn't the TC take the hit "Shock" out of the drive train...therefore, negating the problem?

ALOHA

[CRUZTAKER]

Very interesting reading indeed.

I have a 3000 stall on my unmodded tranny with the j-mod.

Most recently I have had some issues, but only after several hundred miles on a hot tranny. It will occationally hestitate on the upshift when at highway speeds and going wot with the od off.

I likely will need to have a thorough going over after the blower install.

Again, if anyone wants the drawings, PM me with an email addy and I will send Jerry W's originals, and an edited version by a newer member for a less aggressive option.;)

[shami02]

Cruztaker,

I would really like the Jerry W. documentation Cruz, and any other updated you have... Please send it to me, I believe my email address is on the site if not I post it to you.

MarauderJack,

I would be very interested in how well the j-mod works for you I also have high milage and now quite a few SC'ed miles (I'm over 100K) on my car. My trany is still a bit sloppy on the shifts and I would like to harden it up some. I plan on taking it out and doing a complete rebuild sometime late next year (when I save up enough money to build a new motor). But until then... stepping up the trans a notch or two would be just great! Please keep this thread going, I am interested.

[Zack]

Cruztaker,

I would really like the Jerry W. documentation Cruz, and any other updated you have... Please send it to me, I believe my email address is on the site if not I post it to you.

MarauderJack,

I would be very interested in how well the j-mod works for you I also have high milage and now quite a few SC'ed miles (I'm over 100K) on my car. My trany is still a bit sloppy on the shifts and I would like to harden it up some. I plan on taking it out and doing a complete rebuild sometime late next year (when I save up enough money to build a new motor). But until then... stepping up the trans a notch or two would be just great! Please keep this thread going, I am interested.


If your trans is sloppy now, just wait and have it built right.

I just picked up a 31k Trilogy MM and the trans is toast :mad2:

[JACook]

Thanks Jeff,
Where might I find Jerry's "Tutorials" on these subjects??


Most of the "good stuff" is found on the TCCoA site.
In particular, Jerry's excellent "Ford OD Transmissions 101" article-
http://www.tccoa.com/articles/tranny/index.html#

Jerry produced a set of updated "J-Mod" instructions for the valve body in the Marauder.
I believe those are the ones that Cruztaker has.


I did the full J-mod. I have a 3500 stall and it really made a big difference. I am very happy with the way it turned out. I still dont think its near as harsh as it sounds though. The way I was told it was too harsh of shifts. That is not the case at all.

With a stock converter, the power-on shifts are not objectionable. I also did the full J-Mod
treatment, and am pretty happy with the shifts, EXCEPT- If I happen to jump out of the
throttle right about when the 1-2 shift is about to happen, it's REALLY harsh.

Next fluid change, the 1-2 accumulator spring is going back in...

[lifespeed]

I had a '97 CV with a new-from-ford 4R70W that had been updated with current electrical wiring and line pressure solenoid. I did the J-mod, and the shifts were perfect. Firm but not overly harsh. Then I had the computer tuned and line pressure increased (by Jerry himself, actually) and the result was overly harsh.

The reason I relate this story, is I wonder if it wouldn't make more sense to do the computer tuning first, before deciding how aggressive to go in the valve body, accumulator springs and separator plate, if it all?

How good does this tranny work after increasing the line pressure in the computer? Anybody have experience here?

[hidperf]

I would think that by increasing line pressure you increase the risk of leakage between passages through a weak/old valve body gasket. I thought of doing this with my tuner before doing the J-mod, but now I'm thinking the J-mod first and if that's not enough, then uppping the line pressure via tuning.

[Zack]

.

Next fluid change, the 1-2 accumulator spring is going back in...

I cant give you the exact part #, but you can change the spring that you want to replace thats halfway between no spring and the stock spring.

[Marauderjack]

Well.....

I just buttoned it back up and took it out for a spin and it REALLY is "Snappy".....especially the 1-2 above 3000 RPM's!!!:eek:

I'm with you Jeff......If the 1-2 accumulator spring will tone it down a bit I will probably put it back in too!!!:beer:

I have not gone WOT yet but probably will soon.....Hope it don't go BOOM!!!:shake:

I also found a check ball jammed in the separator plate and had to find another on in town!!:cool:

Thanks for all the help guys!!!:bows:

Marauderjack:burnout:

[KillJoy]

Very interesting discussion here.....

:dunno:

KillJoy

[Krytin]

I would think that by increasing line pressure you increase the risk of leakage between passages through a weak/old valve body gasket. I thought of doing this with my tuner before doing the J-mod, but now I'm thinking the J-mod first and if that's not enough, then uppping the line pressure via tuning.
If you do the "J-mod" - you won't want to increase the line pressure!

[Marauderjack]

If you do the "J-mod" - you won't want to increase the line pressure!

AMEN TO THAT!!!!:bows:

[Zack]

If you do the "J-mod" - you won't want to increase the line pressure!

And thats where the big debate stems from, ^^^that statement.

You want to increase line pressure for maximum longevity.

[Marauderjack]

You want to increase line pressure for maximum longevity.

And WHIPLASH!!!:eek:

[Marauderjack]

This AM I went to about 5 PSI and the 1-2 shift was not as harsh as mid throttle with little or no boost!!:beer:

If I'm at 2-3 PSI and the shift takes the RPM's down IMMEDIATELY to the vacuum side it "Noses Over" because the surge valve opens and torque is greatly reduced??:confused:

I can get used to it....I think!!??:cool:

I'll drive it awhile and possibly put the spring back in the 1-2 accumulator like Jeff mentioned.:D

GREAT Mod though as far as I'm concerned!!:banana:

Marauderjack:bandit:

[Glenn]

I am no expert on trans mods, I can only tell you what I have done and my results and it's the results that count. Lidio did his "trans shift kit" install on my MM and then tuned the car. It is completely stock until I go WOT and then it shifts firmer, but not FIRM. I have the 3000 PI TC. The car runs 11.96 and I have 63,000 hard miles on the trans. IMHO, you must do any trans mod in conjunction with a good trans shift schedule and tune. You can not do one without the other. I have over the past 4 years only taken the best and proven mods to get my MM into the 11s. Hard track results are what counts unless you are modding ONLY for the street. Any trans mod must be incorporated into a good tune to obtain optimium results.
Let the flames begin - :flamer:


Glenn :burnout:

Lidio shop tour: http://videos.streetfire.net/video/56ff3652-4923-411a-b41a-999c000f8c38.htm

[Marauderjack]

I am no expert on trans mods, I can only tell you what I have done and my results and it's the results that count. Lidio did his "trans shift kit" install on my MM and then tuned the car. It is completely stock until I go WOT and then it shifts firmer, but not FIRM. I have the 3000 PI TC. The car runs 11.96 and I have 63,000 hard miles on the trans. IMHO, you must do any trans mod in conjunction with a good trans shift schedule and tune. You can not do one without the other. I have over the past 4 years only taken the best and proven mods to get my MM into the 11s. Hard track results are what counts unless you are modding ONLY for the street. Any trans mod must be incorporated into a good tune to obtain optimium results.
Let the flames begin - :flamer:


Glenn :burnout:

Lidio shop tour: http://videos.streetfire.net/video/56ff3652-4923-411a-b41a-999c000f8c38.htm

Hey Glenn....

I have been through dozens and dozens of tunes with shift pressure increased, shift points changed, TC lock in 4th only, TC lock in 3rd or 4th about 45 MPH....and the list goes on!!:beer: I initially used SCT but due to the fact my FIT ProCharger uses DiabloSport I was compelled to go with that and it is just fine with ALL the help I got from Dave Lamberson who does Greg's tuning work!!:bows:

As a result I found that with trans Pressures "Maxed Out" in the tuner it just wasn't enough for me but pretty good for a street car......so I had Dave reduce my shift pressures back to "Stock" and did the "J-Mod" on Friday.....NIGHT & DAY difference!!:eek:

BTW....I have one tune with the TC locking ONLY in 4th above 45 MPH, one with TC locking in 3rd or 4th with light throttle at 43 MPH (with O/D OFF it locks in 3rd) with "Stock" shift points and the one I run the most is just like the second one but the shift points are a bit higher...avoiding the quick 1-2 "Stock" shift at light throttle (Dave does not allow a 2-1 down shift above 30 MPH...understandable)....This allows me to stay in 1st above 20 MPH.....actually pretty nice for me!!:D

I think I will get used to the J-Mod and 1-2 firmness but if not Darrin has a lighter spring for the 1-2 accumulator that I will put in!!:beer: Easy to do with the valve body in place!!:bows:

BTW.....I'm VERY pleased with this Mod!!:banana:

Marauderjack:burnout:

[JACook]

I think I will get used to the J-Mod and 1-2 firmness but if not Darrin has a lighter spring for the 1-2 accumulator that I will put in!!

Zack also mentioned this lighter accumulator spring. Since I'm planning to put the spring back
in next time I service the transmission, I'd be very interested in knowing the part number, or
application, for this lighter spring. Might be just the ticket to ease the harsh drop-throttle 1-2
shift, but still keep the throttle-on firmness that I like without the spring.

Think you could get Darrin to spill the beans? I think this info would be beneficial to a lot of us
here. Otherwise, tell me how to contact Darrin so's I can buy one from him...

[Marauderjack]

Jeff,

http://www.bc-automotive.com/

317-514-0816

I have PM'd him about the lighter spring but he has been on vacation for two weeks and has not responded yet......I'll probably hear from him Wednesday and will let you know what he says unless you speak with him first or he replies here??:beer:

I just bumped my 1-2 shift RPM's to 6200 and hit the rev limiter (11 PSI also)....thought I'd broken something!!!:eek: Backed it back down to 5900.....since the shift is so firm and carries the RPM farther with wheel spin....I guess!!

BTW....the 1-2 shift is actually pretty mild at WOT since the wheels are slipping......mid throttle is a different story!!:shake:

Let me know if you talk to Darrin!!:D

Marauderkjack:bandit:

[jvillerauder]

i did the jmod on my 2002 cvlxsport at 225,000 miles the transmission runs great i recomend it

[Marauderjack]

FWIW......I found out that my tunes did not have the TV pressure turned back to "Stock" and in fact they were 70% high!!!:argue::mad2:

Mike at Unique Tuning in Bluffton, SC fixed it and now the J-Mod is GREAT!!!:bows::beer: Still firm but not crazy like it was!!:shake:

Wonder if Jeff Cook ever put his accumulator spring back in??:confused:

Marauderjack:burnout::burnout:

[Local Boy]

Don't know about JACook...

But, I put my spring back in, a few weeks after reading these posts ('07)....MUCH better now!

ALOHA

[Marauderjack]

Darrin sent me a lighter Ford spring and it helped but setting the TV (throttle valve) setting to stock did the most!!!:bows:

If anyone needs and OEM separator plate to experiment with I have a brand new one I got from Darrin!! I was going back to stock until I discovered the TV pressures too high!!:shake:

Marauderjack:burnout: