J-mod review

[MMarauder03]

Well tore into the tranny last night and just took a few pictures of the assembly of the valve body last night that I'll post up later.

Changes I made; Removed all 1-2 accumulator springs, removed lower 2-3 accumulator spring, drilled tough plate separator plate on the bigger end of the spectrum, Basically cleaned everything really well with brake parts cleaner, made sure all valves were not scored and checked overall condition of the valve body. Deep transmission pan from Dennis Reinhart (just be sure if you order the pan through him, move the plug over one hole otherwise you're going to hassle with it, otherwise fitment is perfect, no leaks)

When in park selecting a gear the gears engage much faster, in just a fraction of a second. WOT not a huge difference aside from a really firm 2-3 shift, manual 1-2 very very firm and will spin the tires, manual 2-1 engages much smoother and scuffles the tires from a 30 mph roll. O/D off/on engages much faster and not sloppily like before with just a tune. Partial throttle its a whole new animal, split second shifts make it easier on the clutches and they are smooth, its not too jerky unless you are 3/4 throttle in which case, you're asking for it ;).

Took about 5-6 hours and 4 cans of brake parts cleaner, 11 quarts of Castrol Mercon V and 2 rolls of paper towels and a shower! LOL I did this all on ramps so it was pretty messy to say the least. Overall a great mod, and makes me love the car even more than I already did. :burnout:

If you have any questions feel free to ask!!

[MMarauder03]

Really? Not one person was wondering about how the Jmod would benefit them or how to do it yourself? Crazy

[1stMerc]

Don't be upset. You have to realize the J-mod is old news and has been done by many, long before you came along.

Enjoy, and congrats on your success.

[Seneca]

Don't be upset. You have to realize the J-mod is old news and has been done by many, long before you came along.

Enjoy, and congrats on your success. What he said... But Enjoy!! :D

[MMarauder03]

Don't be upset. You have to realize the J-mod is old news and has been done by many, long before you came along.

Enjoy, and congrats on your success.

Haha, I'm not upset, I just hear a lot of people asking about the Jmod so I figured I'd post something up. Most people, I assume take it to a transmission shop, but it's not necessary. If you have the right tools and can be very cost effective and "fun" to learn how to do it yourself! No hurt feelings here

[Krytin]

I did it myself too!
80K+ trouble free miles ago!

[capt512]

I did mine today as well. Had previously done one on a 01 vic, so pretty much the same shuffle. Didn't remove any of the springs as I hated how hard my 01 beat me (though I also had a tune with max pressure so maybe that made it bad), just cleaned everything up and enlarged holes. Haven't driven it yet...

[REAL4WD]

very nice, i wish i had the means to do the jmod myself

[ChiTownMaraud3r]

I would do the j mod but it sounds tricky.. and a lot of time to do it. Anyone know of any shops out there that do this legitimately?

[ctrlraven]

I had another MM owner who is a Ford mechanic do mine along with some solenoids being replaced and pressure regulator valve in the valvebody replaced as well.

[capt512]

Chitown - Its not really difficult, just takes a little time. I've done two, and they were my first ever experiences in a transmission - no problem. Hardest part I've found is guessing the amount of fluid to put back in. The longest part of time is waiting on the fluid to drain from the valve body before dropping it. Did mine in 2-3 hours and could have done it quicker, but didn't have the car high enough in the air (so I was scrunched)...plus it was over 100...so I took a few breaks to not have a heat stroke. :) As far as shops that do it, I would see if you can find any performance tranny shops, if not bring the info from the PDF to a few different shops and gauge thier feel towards doing it.

[justbob]

Step one ~ drill hole in pan. There, I saved you all 30 minutes and a bath. :)


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[capt512]

BTW I drove mine today after just enlarging holes and can say its still impressive. Shifts Mich quicker and seems a lot better in first for some reason.

[Marauderjack]

Step one ~ drill hole in pan. There, I saved you all 30 minutes and a bath. :)


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Nope.....the "Mercon V Shower" happens when you drop the valve body!!:eek:

BTW, my 1-2 shift was ridiculous HARSH at first!! :mad2: The car was very dangerous in the rain!!:shake:

I put a Mustang spring in the 1-2 accumulator and that helped some but softening the 1-2 shift at light throttle in the tune fixed it!!:beer::bows:

[justbob]

Nope.....the "Mercon V Shower" happens when you drop the valve body!!:eek:

BTW, my 1-2 shift was ridiculous HARSH at first :mad2:......put a Mustang spring in the 1-2 accumulator that helped but softening the shift at light throttle in the tune fixed it!!:beer::bows:

Nah. That's too easy removing the valve body. Be patient and let her drain with one bolt backed out a tad. I just hate taking the pan off full of fluid. Drain plug FTW!



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[Marauderjack]

Nah. That's too easy removing the valve body. Be patient and let her drain with one bolt backed out a tad. I just hate taking the pan off full of fluid. Drain plug FTW!



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Yep, I did the one bolt thing and used a vacuum can to pull most of the fluid out of the pan so pan removal wasn't very messy!!:beer:

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=93490&catalogId=10001&langId=-1&storeId=11151&storeNum=10106&subdeptNum=10434&classNum=10440

[99SVT]

I did the J-mod to my Lincoln Mk VIII and Marauder, easily done in an afternoon. Not a lot of special tools needed, a good set of snap ring pliers help a lot when disassembling the accumulators.

[RF Overlord]

I just hate taking the pan off full of fluid. Drain plug FTW!Amen, brah. That was one of the first things I did to Phoebe when we got her. The Blackbird got a U-Haul pan.

[Rockettman]

...As far as shops that do it, I would see if you can find any performance tranny shops, if not bring the info from the PDF to a few different shops and gauge thier feel towards doing it.

There's a PDF for this?
Do tell. Do tell.
:beer:

[ctrlraven]

There's a PDF for this?
Do tell. Do tell.
:beer:
http://www.crownvic.net/tech/4R70Wnotes.pdf

[Rockettman]

^^^ Thanks - I will save that.

It's for a 4R70 though...I have the 75. Is it the same?

[ctrlraven]

It's all the same, I have a 75 as well.

[justbob]

I can't believe how tame and lame the jmod is on the stock tune! I must of had my line pressure REALLY jacked.

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[ctrlraven]

I can't believe how tame and lame the jmod is on the stock tune! I must of had my line pressure REALLY jacked.

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Really? Maybe it's just our cars cause a lot of the CVPI guys have good results after they do the jmod on a stock tune car.

[99SVT]

The J-mod is quite tame, I had the line pressure raised in the tune as well. It turned out to be a bit much as the stub shaft broke after a year of track use. Now I'm running a Lentech 4R70W with no adjustments to line pressure via tuning and it shifts nearly as hard as the the tune and J-mod combo did.

[justbob]

Really? Maybe it's just our cars cause a lot of the CVPI guys have good results after they do the jmod on a stock tune car.
Maybe? But I went back to "stock...ish" last week :eek: for emissions.. I was just used to the way it's been for the last couple years and MY GOD what a tame shift!

Passed emissions today, two hours wrenching tomorrow and all will be back to NORMAL! :burnout:

[ctrlraven]

Mine was kind of soft for the first few days then something worked itself out and I had to back the shift line pressure down to zero, even with a 3500 stall they were a little too firm.