J-mod on the family car - My experience

[MinnesotaMuscle]

Well I had to drop the pan to do a filter and flush so I figured what the heck for $3.50 in gaskets and the price of two new drill bits I could do the mod. With the directions posted in the link below, it was crazy easy, like a step by step on how to tie your shoe laces! My car is all stock, plus I haul the wife and three youngn's around in it all the time so I was concerned about getting to aggressive with it.
I left all the springs just the way they were and only did the drilling. I did drill out to the max dimensions using the 7/64 bit and the 3/32 bit for the reverse. Overall I LOVE IT! Completely mild at 1/4 and 1/2 throttle ( around town driving), and at 3/4 throttle its a nice crisp shift, but at WOT its a fantastic snap that doesn't break the tires loose but does raise the front of the car some....If anything I wold have gone a bit more on the reverse, its a noticeable difference, but could use a tad more.
So, for you guys who are concerned about the EVERYDAY drive ability of the vehicle with this mod, look no further! I am SOOO glad I did this.... :beer:

http://www.mercurymarauder.net/forums/showthread.php?t=6466&highlight=j-mod&page=2

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

[justbob]

I removed my springs and its very smooth yet. This will depend on how your line pressure is set up in your tune, mine is set very low.

[Seneca]

I removed my springs and its very smooth yet. This will depend on how your line pressure is set up in your tune, mine is set very low.
+ 2! Mine shifts very smooth.. Unless you get pass half throttle.. Very crisp.. but not harsh.. Just right.

[NATEHAWK]

I will be doing this mod come this week. how many quarts of fluid do you guys use on this?

[justbob]

Mine took between 9-10. On a Trilogy car I have found using a normal long tranny funnel, melted and dented in about three locations will do the job, or just take the wiper ass. out. Good luck.

[MinnesotaMuscle]

Yep 9 Qrts

[Stranger in the Black Sedan]

What is this doing for a stock-ish car, that you couldn't do better with a tune? You can make the shifts so hard with just the tune that it breaks the tires loose shifting on dry pavement and gives you whiplash

[justbob]

Jerry said it was good.

[Seneca]

What is this doing for a stock-ish car, that you couldn't do better with a tune? You can make the shifts so hard with just the tune that it breaks the tires loose shifting on dry pavement and gives you whiplash Line pressures are ran high to achive Firm Hard shifts with a tuner.. Unlike with the J/mod

[MinnesotaMuscle]

AND...

High line pressure = pump working hard...

pump working hard = possible premature failure...

[JohnE]

This thread has good information in it.

[Mr. Man]

So what would you need to do if you have a tune and want to do the J-mod as well? First is it OK to do this? If it is would you then need to lower the line pressures in the tune? Seems like you would, but being a poor old counntry dirt farmer what do I know.

[fastblackmerc]

I had Marty lower the pressure before I did mine.

[justbob]

So what would you need to do if you have a tune and want to do the J-mod as well? First is it OK to do this? If it is would you then need to lower the line pressures in the tune? Seems like you would, but being a poor old counntry dirt farmer what do I know.

Most tunes have some options that are unlocked for you to modify yourself like shift firmness, gear ratio, tire revolutions, and idle RPM just to name a few.


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