Performance Thoughts on the J mod

SSG Pate · November 22nd, 2011, 09:12 AM

I am thinking about doing the J Mod to my Auto 4R70W I have read that it opens up flow on the valve body causing less wear and tear on the clutches, and allows the stock tranny to hold more power. Has anyone done it and been able to tell a difference before and after? Advise me on your experience with this modification.

Tang Stang · November 22nd, 2011, 09:42 AM

It sounds like you're just referring to the valvebody portion of the J-Mod. Depending on the "level" you choose, the TC you're running, and the actual level of power you're putting through the transmission, the before/after difference will range from slightly to extremely noticeable.

brokenweasel · November 22nd, 2011, 09:58 AM

I have not done it, but I have been happy turning up the pressure via SCT handheld, and at stock power levels I should have no problems.

I have also heard that the 4R70W already has a lot of the J-mod type enhancements to it already vs. the old AOD transmissions.

Have you seen this site before? Jerry's original articles are in here somewhere:
TCCoA | TCCoA

Tang Stang · November 22nd, 2011, 10:35 AM

TCCOA has the main articles, but you'll want to read this addendum for the later model 4R70W's: http://www.crownvic.net/tech/4R70Wnotes.pdf

SSG Pate · November 22nd, 2011, 11:07 AM

I think Ill do this and see how it goes.. Cant hurt anything I suppose, But i really like the way the Stock transmission shifts I dont want it to be firm and jerky.

Tang Stang · November 22nd, 2011, 11:21 AM

What TC and gears are you running, and how much power/tq are you putting through the transmission?

SSG Pate · November 22nd, 2011, 11:38 AM

I have 410 Gears Stock Converter.. as far as power I have no ideal until we dyno. high 400rwhp Range perhaps

Tang Stang · November 22nd, 2011, 11:48 AM

Well, definitely read the entire article (TCCoA Tech Articles), but the comments Jerry made in the link I posted earlier will apply to your transmission. Basically, holes #2, 4, 5, 9, & 11 need to be opened up to ~ .100", and you need to remove the bottom 1-2 and 2-3 accumulator springs. Keeping the holes at .100" will keep the shifts relatively mild, though I would open those holes up to ~ .110" if you're planning on swapping in a higher stalled TC anytime soon, as higher stalled TC's tend to absorb some of the part throttle shift firmness.

November 22nd, 2011, 09:12 AM	#1
SSG Pate Premium Member 00 Mustang GT Vert/88 5.0 Join Date: Sep 2010 Location: Tennessee Posts: 1,766 iTrader: 3 reviews	Performance Thoughts on the J mod I am thinking about doing the J Mod to my Auto 4R70W I have read that it opens up flow on the valve body causing less wear and tear on the clutches, and allows the stock tranny to hold more power. Has anyone done it and been able to tell a difference before and after? Advise me on your experience with this modification. __________________ Proud Iraq and Afghanistan War veteran Powered By MMR 4.75L Stroker, Tuned at Kurgan Motorsports

November 22nd, 2011, 10:35 AM	#4
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	TCCOA has the main articles, but you'll want to read this addendum for the later model 4R70W's: http://www.crownvic.net/tech/4R70Wnotes.pdf __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

November 22nd, 2011, 11:07 AM	#5
SSG Pate Premium Member 00 Mustang GT Vert/88 5.0 Join Date: Sep 2010 Location: Tennessee Posts: 1,766 iTrader: 3 reviews	I think Ill do this and see how it goes.. Cant hurt anything I suppose, But i really like the way the Stock transmission shifts I dont want it to be firm and jerky. __________________ Proud Iraq and Afghanistan War veteran Powered By MMR 4.75L Stroker, Tuned at Kurgan Motorsports

November 22nd, 2011, 11:21 AM	#6
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	What TC and gears are you running, and how much power/tq are you putting through the transmission? __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

November 22nd, 2011, 11:38 AM	#7
SSG Pate Premium Member 00 Mustang GT Vert/88 5.0 Join Date: Sep 2010 Location: Tennessee Posts: 1,766 iTrader: 3 reviews	I have 410 Gears Stock Converter.. as far as power I have no ideal until we dyno. high 400rwhp Range perhaps __________________ Proud Iraq and Afghanistan War veteran Powered By MMR 4.75L Stroker, Tuned at Kurgan Motorsports

November 22nd, 2011, 09:42 AM	#2
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	It sounds like you're just referring to the valvebody portion of the J-Mod. Depending on the "level" you choose, the TC you're running, and the actual level of power you're putting through the transmission, the before/after difference will range from slightly to extremely noticeable. __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

November 22nd, 2011, 11:48 AM	#8
Tang Stang Hardcore Enthusiast 2004 Mustang GT Join Date: Sep 2010 Location: Imperial, MO Posts: 1,961 iTrader: 2 reviews	Well, definitely read the entire article (TCCoA Tech Articles), but the comments Jerry made in the link I posted earlier will apply to your transmission. Basically, holes #2, 4, 5, 9, & 11 need to be opened up to ~ .100", and you need to remove the bottom 1-2 and 2-3 accumulator springs. Keeping the holes at .100" will keep the shifts relatively mild, though I would open those holes up to ~ .110" if you're planning on swapping in a higher stalled TC anytime soon, as higher stalled TC's tend to absorb some of the part throttle shift firmness. __________________ Rod @ AzzKicker Cars 2004 Ford Mustang GT-The Driver-BBK CAI, PP TB & Inlet, Steeda UD's, SLP LM1, & 3.73's. 1990 Mercury Cougar XR7-The Meth Addict-5.0L DOHC Stroker w/2.1L KB SC. 1995 Ford F150-Mud Toy-5.0L, 4x4, 33's, & Warn 8274 Winch

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