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View Full Version : J-Moded tranny, what are you waiting for?



torinodan
04-10-2005, 05:28 AM
I finally found time to do the J-mod to my tranny and all I have to say is WOW I love it. The more I drive it the more I like it. Shift points are dead on with no lag what so ever. Shifts are firm as everything snaps into place. I even have a reduction in RPMs while going down the road, about 200 RPMs lower now. With normal driveing the shifts happen without any delay and at WOT I couldn't stop :D !!!

This is a great mod and it took 3 hours to finish and I highly recommend it to anyone who has been thinking about doing it. The longest part of the Mod was waiting for all the fluid to stop dripping on my head from the valve body. I did remove the 1-2 spring as sudgested and it's great. Thank you Barry for the easy to follow instructions. Now I'm going out to do some more driveing.:burnout:

stevengerard
04-10-2005, 05:47 AM
Sounds great, in todays gasoline market those 200 rpms could pay for those 3 hours in a few hundred miles!

RoyLPita
04-10-2005, 06:42 AM
I'm looking forward to doing that to the beast pictured below.

Embassy
04-10-2005, 09:08 AM
Welcome to the club.

How harsh it is without the 1-2 spring? I removed the 2-3 spring and drilled the plate. I opted to leave my 1-2 spring in place.

torinodan
04-10-2005, 10:51 AM
Welcome to the club.

How harsh it is without the 1-2 spring? I removed the 2-3 spring and drilled the plate. I opted to leave my 1-2 spring in place.
It's not harsh at all. I still hve 3.55 gears so maybe thats why. It's just shifts nice, clean, and fast. No waiting! At WOT on the other hard, it will give a nice hard slap in the face of 2nd gear. By no means is it harsh though.

Krytin
04-10-2005, 01:03 PM
Good deal! Welcome to the club - now watch how fast the rear tires wear from spinning them @ the 1-2 shift. It's all good!

metroplex
04-11-2005, 05:49 AM
I pulled the 1-2 lower spring and the shifts literally rocked the vehicle. It's way too harsh with SCT trans pressure settings. I pulled about 50 psi at the low end, and roughyl 20-30 psi through the throttle positions in the 1-2 table.

Overall, I didn't like it but there was little to no clutch wear.
I replaced the lower spring, and increased the SCT pressure settings by about 10-20 psi and got the same feeling as before but it was more domesticated. :cool:

The later model 4R70Ws don't really NEED the J-Mod unless you're pushing serious hp (300+ hp, like you guys).

torinodan
04-11-2005, 07:23 AM
The 2 bigest reasons why I wanted to do the J-mod was 1: I wanted the much better shifts, 2: with my tune I would get some light pinging whenever the tranny changed from 1st to 2nd gear due to the delay in the original shifting. Now, I can take it all the up and shift at the top side with no pings between shifts. No delay and no usless spike in RPMs when shifting. To me it's about useing the power I have safer. I'm very happy with it.:banana:

Bowman9
04-12-2005, 03:34 PM
Hey guys,

I am not exactly sure what you are talking about when you say "J-mod".
I would like better/firmer shift points for my Marauder, like my 1990 5.0 had, would this help?
You can see my current list of mods in my signature, would these help or hinder a "J-mod" modification.

Bradley G
04-12-2005, 05:45 PM
Thanks Torinodan,

does this mod drastically shorten the life of the transmission?Any one document any gains?
Bradley G

SergntMac
04-12-2005, 06:09 PM
I am not exactly sure what you are talking about when you say "J-mod".

Here is a shortcut to a real learning experience.

http://www.tccoa.com/articles/tranny/transmission/page1.shtml

The writer is Jerry Wrobleski, the Ford engineer who (among other great accomplishments) designed our 4R70W transmission. This white paper will provide all the 411 you need to know, but it can be a long, and technical read. The first time I read it, I walked away shaking my head WTF. But, keep at it, a lot will come clear soon. Jerry has since moved on to greater things with SuperChips Custom Tuning (SCT).

Back maybe a year ago, one of our members here wrote a less technical and 4R70W specific instruction sheet, and dubbed it the "J-Mod." It's floating around somewhere, just ask and someone may be able to FWD you a copy via e-mail. BTW, I believe these instructions are valid for the 4R75W tranny in the '04s.

I suppose that most of you know that the J-Mod is redundant with any transmission changes accomplished by custom tuning, so, you need to have that adjusted once the physical changes to your tranny are complete. Otherwise, your shifts will be overly firm and uncomfortable, and possibly destructive over long term use, depending on your software settings. Happy motoring!

Krytin
04-12-2005, 06:14 PM
Here is a shortcut to a real learning experience.

http://www.tccoa.com/articles/tranny/transmission/page1.shtml

The writer is Jerry Wrobleski, the Ford engineer who (among other great accomplishments) designed our 4R70W transmission. This white paper will provide all the 411 you need to know, but it can be a long, and technical read. The first time I read it, I walked away shaking my head WTF. But, keep at it, a lot will come clear soon. Jerry has since moved on to greater things with SuperChips Custom Tuning (SCT).

Back maybe a year ago, one of our members here wrote a less technical and 4R70W specific instruction sheet, and dubbed it the "J-Mod." It's floating around somewhere, just ask and someone may be able to FWD you a copy via e-mail. BTW, I believe these instructions are valid for the 4R75W tranny in the '04s.

I suppose that most of you know that the J-Mod is redundant with any transmission changes accomplished by custom tuning, so, you need to have that adjusted once the physical changes to your tranny are complete. Otherwise, your shifts will be overly firm and uncomfortable, and possibly destructive over long term use, depending on your software settings. Happy motoring!

What he said^^^^.
I performed this mod last year - a little over 10k miles since and no adverse effects detected. I will be changing the fluid/filter in another few months & will post if I find any parts/pieces in the pan!

Bowman9
04-12-2005, 07:34 PM
Here is a shortcut to a real learning experience.

http://www.tccoa.com/articles/tranny/transmission/page1.shtml

...I suppose that most of you know that the J-Mod is redundant with any transmission changes accomplished by custom tuning, so, you need to have that adjusted once the physical changes to your tranny are complete. Otherwise, your shifts will be overly firm and uncomfortable, and possibly destructive over long term use, depending on your software settings...

I guess than that the "J-mod" is not for me, Dennis programmed my SCT9100 for better shift points along with the 4:10 gears.

I'll have to find another way to get that nice quick snap my 5.0 mustang had.

Thanks guys :)

Bradley G
04-13-2005, 01:43 PM
Doesn't make sense to break into the trans to get the same results that a tuner can give.Especially if you have to re-tune after anyway,Won't you need a tuner or a dynotune to adjust the trans pressure?

Bradley G

SergntMac
04-13-2005, 04:00 PM
Won't you need a tuner or a dynotune to adjust the trans pressure? Bradley G
You won't need another dyno tune, Brad, but you will need access to whomever sold you your chip/HHP. Just send that back to the tuner for an adjustment to the line pressures and you're done.

The full J-Mod is a lot more tranny tuning than what you get from reprogramming with a chip/HPP. IMHO, it's worth the PITA.

CRUZTAKER
04-13-2005, 07:59 PM
Thank you Barry for the easy to follow instructions. Now I'm going out to do some more driving.:burnout:
It certainly is a wonderfull enhancement. :up:

Pass the word.

Bradley G
04-16-2005, 03:25 AM
Thanks Mac,

Am I understanding this?
The line pressure is reduced because the holes are drilled larger?
Thanks for you info
Bradley G

You won't need another dyno tune, Brad, but you will need access to whomever sold you your chip/HHP. Just send that back to the tuner for an adjustment to the line pressures and you're done.

The full J-Mod is a lot more tranny tuning than what you get from reprogramming with a chip/HPP. IMHO, it's worth the PITA.

Bradley G
04-16-2005, 03:29 AM
Did you do any comparison befor and after,Is this S-O-P enhancement?

Bradley G


It certainly is a wonderfull enhancement. :up:

Pass the word.

CRUZTAKER
04-16-2005, 06:08 AM
Comparo....?

This is one of those mods similar to window tinting.

If you don't notice the difference, your'e blind...or in this case....dead. :baaa:

fastblackmerc
04-16-2005, 06:17 AM
Comparo....?

This is one of those mods similar to window tinting.

If you don't notice the difference, your'e blind...or in this case....dead. :baaa:
Is the J-Mod only for '03's? What would be the maximum line pressure you'd run under WOT? :burnout:

Svashtar
04-16-2005, 03:36 PM
I finally found time to do the J-mod to my tranny and all I have to say is WOW I love it. The more I drive it the more I like it. Shift points are dead on with no lag what so ever. Shifts are firm as everything snaps into place. I even have a reduction in RPMs while going down the road, about 200 RPMs lower now. With normal driveing the shifts happen without any delay and at WOT I couldn't stop :D !!!

This is a great mod and it took 3 hours to finish and I highly recommend it to anyone who has been thinking about doing it. The longest part of the Mod was waiting for all the fluid to stop dripping on my head from the valve body. I did remove the 1-2 spring as sudgested and it's great. Thank you Barry for the easy to follow instructions. Now I'm going out to do some more driveing.:burnout:
You pulled the tranny yourself? I have plenty of hand and air tools, but wouldn't have a clue how to do this.

Norm

Bradley G
04-16-2005, 03:58 PM
I think its just the lower pan.

Barry I believe;) I was just curious if anyone has measured any ET gains.
Is it the same mod from '03-'04?
Bradley G

You pulled the tranny yourself? I have plenty of hand and air tools, but wouldn't have a clue how to do this.

Norm

torinodan
04-18-2005, 07:40 PM
I think its just the lower pan.

Barry I believe;) I was just curious if anyone has measured any ET gains.
Is it the same mod from '03-'04?
Bradley G
It's just the lower pan and should be the same for 03 and 04. Someone should have something to say if the ET got better. I don't think that ET gains would be that much. Other than that it's just way too much fun to break the tires loose on the 1-2 shift.