J-Mod questions

[510paesan]

Recently purchased a '03 300A. Odometer is at 106k. Very healthy, noticed no problems so far. New member to this forum, and so far this site has been VERY helpful. Thank You All

Was reading up a lot and thinking of doing the jmod on my 4r70w myself. Im a transmission mechanic by trade, but not in the sense that you esteemed gentleman may think. I'm an A&P mechanic for a FAA repair station, performing diagnostic repair or overhaul on gearboxes that are otherwise known as CSD's and IDG's.

I've downloaded an old .pdf from the TCCOA site, and watched rizzos video on youtube, and read many, many posts on this forum and others regarding this mod.

I've purchased my new gaskets, new deep pan, was planning on getting all the Sonnax goodies: servo pin kit, regulator kit, boost valve kit, new Superior Tuff plate, and just knocking this out at work one Saturday morning (off the clock, of course)

What should I be aware of here? Simply removing springs and drilling a bunch of holes seems like it could cause damage. Thoughts, suggestions would be much appreciated.

[RubberCtyRauder]

The Jmod was invented by a ford transmission engineer , Jerry Wrobleski or something like that. It lessens friction by speeding up the shift. The only time it might be a trouble is if you wot from a stop on wet roads. The 1-2 shift can get squirrelly.

[chief455]

don't know the video you watched, but I've read / seen enough info to feel comfortable doing it.
pretty much a shift kit - drilled seperator plate passages and spring changes. nothing new.
go for it.

[RubberCtyRauder]

The vid was made by member Rizzo on CVN. He has personally done over a dozen of them . It's a YouTube vid. Link should be a sticky thread over on CVN

[fastblackmerc]

Recently purchased a '03 300A. Odometer is at 106k. Very healthy, noticed no problems so far. New member to this forum, and so far this site has been VERY helpful. Thank You All

Was reading up a lot and thinking of doing the jmod on my 4r70w myself. Im a transmission mechanic by trade, but not in the sense that you esteemed gentleman may think. I'm an A&P mechanic for a FAA repair station, performing diagnostic repair or overhaul on gearboxes that are otherwise known as CSD's and IDG's.

I've downloaded an old .pdf from the TCCOA site, and watched rizzos video on youtube, and read many, many posts on this forum and others regarding this mod.

I've purchased my new gaskets, new deep pan, was planning on getting all the Sonnax goodies: servo pin kit, regulator kit, boost valve kit, new Superior Tuff plate, and just knocking this out at work one Saturday morning (off the clock, of course)

What should I be aware of here? Simply removing springs and drilling a bunch of holes seems like it could cause damage. Thoughts, suggestions would be much appreciated.

nj

If you read up on the reason for the J-Mod you'll find it will actually extend the life of the tranny.

[Logizyme]

You are not adding any holes, rather just opening some up a bit so more fluid flows through. Traditionally JMOD consists of opening a select few holes on the separator plate and removing the 1-2 and 2-3 accumulator springs.

Having modified about 10 cars, and daily'd 3 different variations on the mod (all 2003's BTW) I can say that spring removal is excessive for anything on the street. Seperator plate modification will result in a more throttle based change, while spring removal is just a neck breaking shift even at the lowest of throttles.

What I will say most about it is spring removal will have you spilling your coffee on your way to work and make your friends ask you whats wrong with your transmission.

Alternatively there are softer springs you can use, and I would suggest looking into them. While I would not recommend installing any shift kits, allot that you might find on ebay contain softer 1-2 and 2-3 springs, I run a couple of springs out of an ebay shift kit myself. Something to think about if you want more that stock springs but less than no springs.

Also the JMOD does little to nothing for OD and 3-4 shifts. Doing some extra work and replacing the OD servo piston with a Sonnax kit will help your 3-4 shifts feel closer to your 1-2 and 2-3. The Sonnax servo piston includes a slot with an oring in it for better sealing and includes a preload washer that is optional to preload the inner spring increasing the OD band application even more. This is additional labor and special attention needs to be paid to ensure the piston is properly located on the band when going back together.

I like that you are already thinking about the sonnax valves, not only is replacing wearing valves a good idea but most the sonnax parts are improved designs and some give spring/hole size options to customize how aggressive you want it.

Currently the best setup I have come across is shift kit 1-2 2-3 springs, Sonnax OD piston kit, Sonnax valves, conservative on the separator plate hole sizing. My hot date in the passenger seat is none the wiser when I drive modestly, but when I am driving like a mad man it is fast and firm though all gears.

I've seen allot of people to the traditional mod, just to realize they want to put the springs back in a few months later when the ridiculous shifts becomes just annoying.

[Logizyme]

nj

If you read up on the reason for the J-Mod you'll find it will actually extend the life of the tranny.

arguable. I'm not saying one way or another, but don't believe everything the internet says.

[88grandmarq]

sent you a PM...

[MyBlackBeasts]

Recently purchased a '03 300A. Odometer is at 106k. Very healthy, noticed no problems so far. New member to this forum, and so far this site has been VERY helpful. Thank You All

Was reading up a lot and thinking of doing the jmod on my 4r70w myself. Im a transmission mechanic by trade, but not in the sense that you esteemed gentleman may think. I'm an A&P mechanic for a FAA repair station, performing diagnostic repair or overhaul on gearboxes that are otherwise known as CSD's and IDG's.

I've downloaded an old .pdf from the TCCOA site, and watched rizzos video on youtube, and read many, many posts on this forum and others regarding this mod.

I've purchased my new gaskets, new deep pan, was planning on getting all the Sonnax goodies: servo pin kit, regulator kit, boost valve kit, new Superior Tuff plate, and just knocking this out at work one Saturday morning (off the clock, of course)

What should I be aware of here? Simply removing springs and drilling a bunch of holes seems like it could cause damage. Thoughts, suggestions would be much appreciated.

http://www.mercurymarauder.net/forum...ad.php?t=82460

Not drilling holes, making existing holes larger.

Will not cause damage, will actually reduce trans wear. The jmod speeds up clutch pack engagement which reduces clutch plate slippage time which reduces wear. The longer the pack slips to smooth out the shift the more the clutch material wears = shorter trans life.

This is easiest & cheapest mod you can do to bring on more smiles per mile. Do it & don't look back.

If you ever decide you don't want it, $4 and it's gone (use the HD new plate for jmod & keep the factory plate unmolested to revert if needed).

[loud2004marquis]

Have done two j mods to my own cars with the 1-2 & 2-3 spring removal and drilling out the holes, shifts nice to me I only used the PDF from the Tocca site as a guide. Not hard to do at all. Have fun!

[BigM460]

Would recommend not removing the 1-2 accumulator spring. The slambing 1-2 shift without the spring gets old after a couple weeks.

[Bad_S55]

I don't think I've heard anything on this before, but do you make the holes in the gasket bigger too or do you just put those in?

[Marauderjack]

Would recommend not removing the 1-2 accumulator spring. The slambing 1-2 shift without the spring gets old after a couple weeks.

^^^+10^^^!!

Mine actually shifted so HARD I put a Mustang spring back in......still pretty hard but we softened it in the tune below half throttle.......still hard at WOT but smoooth due to wheel spin!!

The worst part of doing th J-mod is the "Trans Fluid Shower"....quite messy!!

[510paesan]

What I will say most about it is spring removal will have you spilling your coffee on your way to work and make your friends ask you whats wrong with your transmission.

Alternatively there are softer springs you can use, and I would suggest looking into them. While I would not recommend installing any shift kits, allot that you might find on ebay contain softer 1-2 and 2-3 springs, I run a couple of springs out of an ebay shift kit myself. Something to think about if you want more that stock springs but less than no springs.

Well I definitely don't want to have myself or any hot date spilling anything on my leather. do you have p/ns for springs that you would recommend?

I don't think I've heard anything on this before, but do you make the holes in the gasket bigger too or do you just put those in?

yes, you have to enlarge the corresponding holes on the top gasket

[510paesan]

sent you a PM...

Thanks for the pm. From going through a lot of YOUR old posts I was able to find the correct p/n's for the kits I need from Sonnax