J-Mod Information

[Blue)(Fusion]

I've seen this mentioned in a few previous various threads but never saw any specific information posted on AF.

Who does this apply to?
The J-Mod can be performed on any AODE, 4R70W, 4R75W, and 4R75E. These automatic transmissions are either available options or standard in the following vehicles:

• Ford Mustang
• Ford Crown Victoria
• Ford Thunderbird
• Ford F-150
• Mercury Cougar
• Mercury Grand Marquis
• Mercury Marauder
• Lincoln Town Car
• Lincoln Mark VIII
• Anything I miss?

J-Mod: What is it?
The J-Mod (or Jerry's Mod) is named after the Ford Transmission Engineer, Jerry Wroblewski, who helped in the design of the AODE/4R70W transmission and came up with these modifications. The J-Mod is intended to increase shift speed and decrease wear on the clutches of the automatic transmission.

Who can do it?
Anyone with basic hand tools, an ability to follow instructions, and patience can complete this job in their garage in a few hours. The only thing you may not have on hand as a non-mechanic are an inch-pound torque wrench and proper sized drill bits.

What does the job entail?
Well, you will be taking apart the valve body of an automatic transmission. This may sound confusing, scary, downright sadistic, but after doing it myself, it's one of the easier things I've done.

The following are NOT detailed instructions and should not be performed as such without reading the full J-Mod instructions (link below).

A basic synopsis of what will be performed:

• Remove the transmission pan, filter, and automatic transmission fluid (ATF)
• Remove electrical harness from solenoids on the valve body
• Remove the valve body from the transmission housing
• Remove the separator plate from the valve body
• Widen several holes with a drill in the separator plate
• Reinstall separator plate and new gaskets to valve body
• Remove (or replace with a softer) lower 1-2 shift accumulator spring
• Remove 2-3 shift accumulator spring
• Clean all accessible parts, including pan magnet
• Reinstall valve body into transmission housing
• Reconnect electrical harness
• Install new filter
• Reinstall transmission pan
• Refill with Mercon V

Really, how hard is it?
I never ever worked on a transmission of any sort. I also have done only pretty basic mechanical tasks, such as changing oil and changing a few engine bits and pieces (see signature). It took me 4 hours, double checking, and triple checking my work. It was also below freezing on my garage floor and took breaks every 15 minutes or so to regain feeling in my fingers.

What will I need?

• 10 quarts Mercon V (12-14 quarts if you also drain your torque converter)
• Inch-pound torque wrench that can measure 90 inch-pounds
• 10mm socket
• 8mm socket
• Drill & drill bits (see instructions as size varies with horsepower)
• Softer 1-2 lower shift accumulator spring (if you so desire)
• Snap-ring pliers
• Separator plate gaskets (2; see instructions for part numbers)
• Vaseline
• Carb or brake cleaner
• Dielectric grease
• Jack and jackstands

Why remove the springs?
The J-Mod calls for the removal of the 2-3 shift accumulator spring (there is only one) no matter what your horse power range. It really doesn't feel too hard under any situation, but is noticeably better than factory.

The 1-2 shift accumulator has two springs - an upper and a lower. The upper spring should NOT BE REMOVED. The option you have (if your HP level allows for it) is if you want to completely remove the lower spring. If you remove the lower spring, the 1-2 shift will be quite firm under all throttle conditions. If you choose to install a softer spring, you will still get improved shifts, but will be less firm.

I opted to completely remove the 1-2 shift accumulator spring. During daily driving, the shifts are not harsh enough to cause discomfort. When WOT, the tires chirp and is a wonderful feeling being thrown into the back of the seat. Most people say that it shifts faster and more firm than a manual.

Will the J-Mod ruin my transmission?
The J-Mod is actually one of those cases that can increase the life of your transmission. Since the J-Mod reduces the time that the clutches slip (thus shifting) from one gear to the next, the clutch wear and ATF temperatures are reduced. However, if your transmission if already not performing well, this is probably not for you. But who knows, maybe all it needs is new fluid to be restored to health.

Does this make it harder to keep traction in snow?
I did my J-Mod in the dead of winter. Infact, it was snowing several inches the day I did it. I found that the traction was not affected by the quicker/firmer shifts, so long as you drove cautiously - like you should in those conditions anyway.

And where are the detailed instructions?
Glad you're still interested!

These instructions are made with the Panther platform in mind (Crown Victoria, Grand Marquis, Marauder, and Town Car), but are easier to read no matter what vehicle you're doing this on. Be sure to read the instructions below for any part numbers and specifics for your HP range.
http://www.crownvic.net/tech/4R70Wnotes.pdf

The original instructions, including gasket and spring part numbers and drill bit sizes:
http://www.tccoa.com/articles/tranny...on/index.shtml

The J-Mod is covered in Chapters 13 and 14 in the above link.

Feel free to comment, ask questions, and help each other here. If you're in my area, I'd be more than happy to help out or show you what it's like on my car!

[Blue)(Fusion]

FWIW, I did this again on my "new-to-me" car - a mint condition 2006 Mercury Grand Marquis LS with a 4R75E.

Some people mentioned that the 4R75W and 4R75E have much of the J-mod completed by the factory with larger holes in the seperate plate. I found this to be untrue.

Every hole that was to be increased in size was smaller than the required drill bit. One was very close, but slightly smaller than the drill bit.

On this car, being in such great condition, I opted to swap the 1-2 accumulator springs instead of remove the lower 1-2 spring. I removed the original green and inserted a softer light-blue upper 1-2 spring and removed the two lower springs and replaced them with a single purple spring. This resulted in far better than stock shifts, but not as firm of a 1-2 shift as my old 2000 Grand Marquis with no lower 1-2 spring.